#include "libslic3r/libslic3r.h"
#include "slic3r/GUI/Gizmos/GLGizmos.hpp"
#include "GLCanvas3D.hpp"

#include "admesh/stl.h"
#include "polypartition.h"
#include "libslic3r/ClipperUtils.hpp"
#include "libslic3r/PrintConfig.hpp"
#include "libslic3r/GCode/PreviewData.hpp"
#include "libslic3r/Geometry.hpp"
#include "libslic3r/Utils.hpp"
#include "libslic3r/Technologies.hpp"
#include "libslic3r/Tesselate.hpp"
#include "slic3r/GUI/3DScene.hpp"
#include "slic3r/GUI/BackgroundSlicingProcess.hpp"
#include "slic3r/GUI/GLShader.hpp"
#include "slic3r/GUI/GUI.hpp"
#include "slic3r/GUI/PresetBundle.hpp"
#include "slic3r/GUI/Tab.hpp"
#include "slic3r/GUI/GUI_Preview.hpp"
#include "GUI_App.hpp"
#include "GUI_ObjectList.hpp"
#include "GUI_ObjectManipulation.hpp"
#include "I18N.hpp"

#if ENABLE_RETINA_GL
#include "slic3r/Utils/RetinaHelper.hpp"
#endif

#include <GL/glew.h>

#include <wx/glcanvas.h>
#include <wx/bitmap.h>
#include <wx/dcmemory.h>
#include <wx/image.h>
#include <wx/settings.h>
#include <wx/tooltip.h>
#include <wx/debug.h>
#include <wx/fontutil.h>

// Print now includes tbb, and tbb includes Windows. This breaks compilation of wxWidgets if included before wx.
#include "libslic3r/Print.hpp"
#include "libslic3r/SLAPrint.hpp"

#include "wxExtensions.hpp"

#include <tbb/parallel_for.h>
#include <tbb/spin_mutex.h>

#include <boost/log/trivial.hpp>
#include <boost/algorithm/string/predicate.hpp>

#include <iostream>
#include <float.h>
#include <algorithm>
#include <cmath>
#if ENABLE_RENDER_STATISTICS
#include <chrono>
#endif // ENABLE_RENDER_STATISTICS

static const float TRACKBALLSIZE = 0.8f;
static const float GROUND_Z = -0.02f;

static const float GIZMO_RESET_BUTTON_HEIGHT = 22.0f;
static const float GIZMO_RESET_BUTTON_WIDTH = 70.f;

static const float DEFAULT_BG_DARK_COLOR[3] = { 0.478f, 0.478f, 0.478f };
static const float DEFAULT_BG_LIGHT_COLOR[3] = { 0.753f, 0.753f, 0.753f };
static const float ERROR_BG_DARK_COLOR[3] = { 0.478f, 0.192f, 0.039f };
static const float ERROR_BG_LIGHT_COLOR[3] = { 0.753f, 0.192f, 0.039f };
//static const float AXES_COLOR[3][3] = { { 1.0f, 0.0f, 0.0f }, { 0.0f, 1.0f, 0.0f }, { 0.0f, 0.0f, 1.0f } };

namespace Slic3r {
namespace GUI {

Size::Size()
    : m_width(0)
    , m_height(0)
{
}

Size::Size(int width, int height, float scale_factor)
    : m_width(width)
    , m_height(height)
    , m_scale_factor(scale_factor)
{
}

int Size::get_width() const
{
    return m_width;
}

void Size::set_width(int width)
{
    m_width = width;
}

int Size::get_height() const
{
    return m_height;
}

void Size::set_height(int height)
{
    m_height = height;
}

int Size::get_scale_factor() const
{
    return m_scale_factor;
}

void Size::set_scale_factor(int scale_factor)
{
    m_scale_factor = scale_factor;
}

#if !ENABLE_TEXTURES_FROM_SVG
GLCanvas3D::Shader::Shader()
    : m_shader(nullptr)
{
}

GLCanvas3D::Shader::~Shader()
{
    _reset();
}

bool GLCanvas3D::Shader::init(const std::string& vertex_shader_filename, const std::string& fragment_shader_filename)
{
    if (is_initialized())
        return true;

    m_shader = new GLShader();
    if (m_shader != nullptr)
    {
        if (!m_shader->load_from_file(fragment_shader_filename.c_str(), vertex_shader_filename.c_str()))
        {
            std::cout << "Compilaton of shader failed:" << std::endl;
            std::cout << m_shader->last_error << std::endl;
            _reset();
            return false;
        }
    }

    return true;
}

bool GLCanvas3D::Shader::is_initialized() const
{
    return (m_shader != nullptr);
}

bool GLCanvas3D::Shader::start_using() const
{
    if (is_initialized())
    {
        m_shader->enable();
        return true;
    }
    else
        return false;
}

void GLCanvas3D::Shader::stop_using() const
{
    if (m_shader != nullptr)
        m_shader->disable();
}

void GLCanvas3D::Shader::set_uniform(const std::string& name, float value) const
{
    if (m_shader != nullptr)
        m_shader->set_uniform(name.c_str(), value);
}

void GLCanvas3D::Shader::set_uniform(const std::string& name, const float* matrix) const
{
    if (m_shader != nullptr)
        m_shader->set_uniform(name.c_str(), matrix);
}

const GLShader* GLCanvas3D::Shader::get_shader() const
{
    return m_shader;
}

void GLCanvas3D::Shader::_reset()
{
    if (m_shader != nullptr)
    {
        m_shader->release();
        delete m_shader;
        m_shader = nullptr;
    }
}
#endif // !ENABLE_TEXTURES_FROM_SVG

GLCanvas3D::LayersEditing::LayersEditing()
    : m_enabled(false)
    , m_z_texture_id(0)
    , m_model_object(nullptr)
    , m_object_max_z(0.f)
    , m_slicing_parameters(nullptr)
    , m_layer_height_profile_modified(false)
    , state(Unknown)
    , band_width(2.0f)
    , strength(0.005f)
    , last_object_id(-1)
    , last_z(0.0f)
    , last_action(LAYER_HEIGHT_EDIT_ACTION_INCREASE)
{
}

GLCanvas3D::LayersEditing::~LayersEditing()
{
    if (m_z_texture_id != 0)
    {
        glsafe(::glDeleteTextures(1, &m_z_texture_id));
        m_z_texture_id = 0;
    }
    delete m_slicing_parameters;
}

const float GLCanvas3D::LayersEditing::THICKNESS_BAR_WIDTH = 70.0f;
const float GLCanvas3D::LayersEditing::THICKNESS_RESET_BUTTON_HEIGHT = 22.0f;

bool GLCanvas3D::LayersEditing::init(const std::string& vertex_shader_filename, const std::string& fragment_shader_filename)
{
    if (!m_shader.init(vertex_shader_filename, fragment_shader_filename))
        return false;

    glsafe(::glGenTextures(1, (GLuint*)&m_z_texture_id));
    glsafe(::glBindTexture(GL_TEXTURE_2D, m_z_texture_id));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1));
    glsafe(::glBindTexture(GL_TEXTURE_2D, 0));

    return true;
}

void GLCanvas3D::LayersEditing::set_config(const DynamicPrintConfig* config)
{ 
    m_config = config;
    delete m_slicing_parameters;
    m_slicing_parameters = nullptr;
    m_layers_texture.valid = false;
}

void GLCanvas3D::LayersEditing::select_object(const Model &model, int object_id)
{
    const ModelObject *model_object_new = (object_id >= 0) ? model.objects[object_id] : nullptr;
    // Maximum height of an object changes when the object gets rotated or scaled.
    // Changing maximum height of an object will invalidate the layer heigth editing profile.
    // m_model_object->raw_bounding_box() is cached, therefore it is cheap even if this method is called frequently.
	float new_max_z = (model_object_new == nullptr) ? 0.f : model_object_new->raw_bounding_box().size().z();
	if (m_model_object != model_object_new || this->last_object_id != object_id || m_object_max_z != new_max_z ||
        (model_object_new != nullptr && m_model_object->id() != model_object_new->id())) {
        m_layer_height_profile.clear();
        m_layer_height_profile_modified = false;
        delete m_slicing_parameters;
        m_slicing_parameters   = nullptr;
        m_layers_texture.valid = false;
        this->last_object_id   = object_id;
        m_model_object         = model_object_new;
        m_object_max_z         = new_max_z;
    }
}

bool GLCanvas3D::LayersEditing::is_allowed() const
{
    return m_shader.is_initialized() && m_shader.get_shader()->shader_program_id > 0 && m_z_texture_id > 0;
}

bool GLCanvas3D::LayersEditing::is_enabled() const
{
    return m_enabled;
}

void GLCanvas3D::LayersEditing::set_enabled(bool enabled)
{
    m_enabled = is_allowed() && enabled;
}

void GLCanvas3D::LayersEditing::render_overlay(const GLCanvas3D& canvas) const
{
    if (!m_enabled)
        return;

    const Rect& bar_rect = get_bar_rect_viewport(canvas);
    const Rect& reset_rect = get_reset_rect_viewport(canvas);

    _render_tooltip_texture(canvas, bar_rect, reset_rect);
    _render_reset_texture(reset_rect);
    _render_active_object_annotations(canvas, bar_rect);
    _render_profile(bar_rect);
}

float GLCanvas3D::LayersEditing::get_cursor_z_relative(const GLCanvas3D& canvas)
{
    const Vec2d mouse_pos = canvas.get_local_mouse_position();
    const Rect& rect = get_bar_rect_screen(canvas);
    float x = (float)mouse_pos(0);
    float y = (float)mouse_pos(1);
    float t = rect.get_top();
    float b = rect.get_bottom();

    return ((rect.get_left() <= x) && (x <= rect.get_right()) && (t <= y) && (y <= b)) ?
        // Inside the bar.
        (b - y - 1.0f) / (b - t - 1.0f) :
        // Outside the bar.
        -1000.0f;
}

bool GLCanvas3D::LayersEditing::bar_rect_contains(const GLCanvas3D& canvas, float x, float y)
{
    const Rect& rect = get_bar_rect_screen(canvas);
    return (rect.get_left() <= x) && (x <= rect.get_right()) && (rect.get_top() <= y) && (y <= rect.get_bottom());
}

bool GLCanvas3D::LayersEditing::reset_rect_contains(const GLCanvas3D& canvas, float x, float y)
{
    const Rect& rect = get_reset_rect_screen(canvas);
    return (rect.get_left() <= x) && (x <= rect.get_right()) && (rect.get_top() <= y) && (y <= rect.get_bottom());
}

Rect GLCanvas3D::LayersEditing::get_bar_rect_screen(const GLCanvas3D& canvas)
{
    const Size& cnv_size = canvas.get_canvas_size();
    float w = (float)cnv_size.get_width();
    float h = (float)cnv_size.get_height();

    return Rect(w - thickness_bar_width(canvas), 0.0f, w, h - reset_button_height(canvas));
}

Rect GLCanvas3D::LayersEditing::get_reset_rect_screen(const GLCanvas3D& canvas)
{
    const Size& cnv_size = canvas.get_canvas_size();
    float w = (float)cnv_size.get_width();
    float h = (float)cnv_size.get_height();

    return Rect(w - thickness_bar_width(canvas), h - reset_button_height(canvas), w, h);
}

Rect GLCanvas3D::LayersEditing::get_bar_rect_viewport(const GLCanvas3D& canvas)
{
    const Size& cnv_size = canvas.get_canvas_size();
    float half_w = 0.5f * (float)cnv_size.get_width();
    float half_h = 0.5f * (float)cnv_size.get_height();

    float zoom = (float)canvas.get_camera().get_zoom();
    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;

    return Rect((half_w - thickness_bar_width(canvas)) * inv_zoom, half_h * inv_zoom, half_w * inv_zoom, (-half_h + reset_button_height(canvas)) * inv_zoom);
}

Rect GLCanvas3D::LayersEditing::get_reset_rect_viewport(const GLCanvas3D& canvas)
{
    const Size& cnv_size = canvas.get_canvas_size();
    float half_w = 0.5f * (float)cnv_size.get_width();
    float half_h = 0.5f * (float)cnv_size.get_height();

    float zoom = (float)canvas.get_camera().get_zoom();
    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;

    return Rect((half_w - thickness_bar_width(canvas)) * inv_zoom, (-half_h + reset_button_height(canvas)) * inv_zoom, half_w * inv_zoom, -half_h * inv_zoom);
}


bool GLCanvas3D::LayersEditing::_is_initialized() const
{
    return m_shader.is_initialized();
}

void GLCanvas3D::LayersEditing::_render_tooltip_texture(const GLCanvas3D& canvas, const Rect& bar_rect, const Rect& reset_rect) const
{
    // TODO: do this with ImGui

    if (m_tooltip_texture.get_id() == 0)
    {
        std::string filename = resources_dir() + "/icons/variable_layer_height_tooltip.png";
        if (!m_tooltip_texture.load_from_file(filename, false, true))
            return;
    }

#if ENABLE_RETINA_GL
    const float scale = canvas.get_canvas_size().get_scale_factor();
#else
    const float scale = canvas.get_wxglcanvas()->GetContentScaleFactor();
#endif
    const float width = (float)m_tooltip_texture.get_width() * scale;
    const float height = (float)m_tooltip_texture.get_height() * scale;

    float zoom = (float)canvas.get_camera().get_zoom();
    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
    float gap = 10.0f * inv_zoom;

    float bar_left = bar_rect.get_left();
    float reset_bottom = reset_rect.get_bottom();

    float l = bar_left - width * inv_zoom - gap;
    float r = bar_left - gap;
    float t = reset_bottom + height * inv_zoom + gap;
    float b = reset_bottom + gap;

    GLTexture::render_texture(m_tooltip_texture.get_id(), l, r, b, t);
}

void GLCanvas3D::LayersEditing::_render_reset_texture(const Rect& reset_rect) const
{
    if (m_reset_texture.get_id() == 0)
    {
        std::string filename = resources_dir() + "/icons/variable_layer_height_reset.png";
        if (!m_reset_texture.load_from_file(filename, false, true))
            return;
    }

    GLTexture::render_texture(m_reset_texture.get_id(), reset_rect.get_left(), reset_rect.get_right(), reset_rect.get_bottom(), reset_rect.get_top());
}

void GLCanvas3D::LayersEditing::_render_active_object_annotations(const GLCanvas3D& canvas, const Rect& bar_rect) const
{
    m_shader.start_using();

    m_shader.set_uniform("z_to_texture_row", float(m_layers_texture.cells - 1) / (float(m_layers_texture.width) * m_object_max_z));
	m_shader.set_uniform("z_texture_row_to_normalized", 1.0f / (float)m_layers_texture.height);
    m_shader.set_uniform("z_cursor", m_object_max_z * this->get_cursor_z_relative(canvas));
    m_shader.set_uniform("z_cursor_band_width", band_width);
    m_shader.set_uniform("object_max_z", m_object_max_z);

    glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
    glsafe(::glBindTexture(GL_TEXTURE_2D, m_z_texture_id));

    // Render the color bar
    float l = bar_rect.get_left();
    float r = bar_rect.get_right();
    float t = bar_rect.get_top();
    float b = bar_rect.get_bottom();

    ::glBegin(GL_QUADS);
    ::glNormal3f(0.0f, 0.0f, 1.0f);
    ::glTexCoord2f(0.0f, 0.0f); ::glVertex2f(l, b);
    ::glTexCoord2f(1.0f, 0.0f); ::glVertex2f(r, b);
    ::glTexCoord2f(1.0f, 1.0f); ::glVertex2f(r, t);
    ::glTexCoord2f(0.0f, 1.0f); ::glVertex2f(l, t);
    glsafe(::glEnd());
    glsafe(::glBindTexture(GL_TEXTURE_2D, 0));

    m_shader.stop_using();
}

void GLCanvas3D::LayersEditing::_render_profile(const Rect& bar_rect) const
{
    //FIXME show some kind of legend.

    if (!m_slicing_parameters)
        return;

    // Make the vertical bar a bit wider so the layer height curve does not touch the edge of the bar region.
    float scale_x = bar_rect.get_width() / (float)(1.12 * m_slicing_parameters->max_layer_height);
    float scale_y = bar_rect.get_height() / m_object_max_z;
    float x = bar_rect.get_left() + (float)m_slicing_parameters->layer_height * scale_x;

    // Baseline
    glsafe(::glColor3f(0.0f, 0.0f, 0.0f));
    ::glBegin(GL_LINE_STRIP);
    ::glVertex2f(x, bar_rect.get_bottom());
    ::glVertex2f(x, bar_rect.get_top());
    glsafe(::glEnd());

    // Curve
    glsafe(::glColor3f(0.0f, 0.0f, 1.0f));
    ::glBegin(GL_LINE_STRIP);
    for (unsigned int i = 0; i < m_layer_height_profile.size(); i += 2)
        ::glVertex2f(bar_rect.get_left() + (float)m_layer_height_profile[i + 1] * scale_x, bar_rect.get_bottom() + (float)m_layer_height_profile[i] * scale_y);
    glsafe(::glEnd());
}

void GLCanvas3D::LayersEditing::render_volumes(const GLCanvas3D& canvas, const GLVolumeCollection &volumes) const
{
    assert(this->is_allowed());
    assert(this->last_object_id != -1);
    GLint shader_id = m_shader.get_shader()->shader_program_id;
    assert(shader_id > 0);

    GLint current_program_id;
    glsafe(::glGetIntegerv(GL_CURRENT_PROGRAM, &current_program_id));
    if (shader_id > 0 && shader_id != current_program_id)
        // The layer editing shader is not yet active. Activate it.
        glsafe(::glUseProgram(shader_id));
    else
        // The layer editing shader was already active.
        current_program_id = -1;

    GLint z_to_texture_row_id               = ::glGetUniformLocation(shader_id, "z_to_texture_row");
    GLint z_texture_row_to_normalized_id    = ::glGetUniformLocation(shader_id, "z_texture_row_to_normalized");
    GLint z_cursor_id                       = ::glGetUniformLocation(shader_id, "z_cursor");
    GLint z_cursor_band_width_id            = ::glGetUniformLocation(shader_id, "z_cursor_band_width");
    GLint world_matrix_id                   = ::glGetUniformLocation(shader_id, "volume_world_matrix");
    GLint object_max_z_id                   = ::glGetUniformLocation(shader_id, "object_max_z");
    glcheck();

    if (z_to_texture_row_id != -1 && z_texture_row_to_normalized_id != -1 && z_cursor_id != -1 && z_cursor_band_width_id != -1 && world_matrix_id != -1) 
    {
        const_cast<LayersEditing*>(this)->generate_layer_height_texture();

        // Uniforms were resolved, go ahead using the layer editing shader.
        glsafe(::glUniform1f(z_to_texture_row_id, GLfloat(m_layers_texture.cells - 1) / (GLfloat(m_layers_texture.width) * GLfloat(m_object_max_z))));
        glsafe(::glUniform1f(z_texture_row_to_normalized_id, GLfloat(1.0f / m_layers_texture.height)));
        glsafe(::glUniform1f(z_cursor_id, GLfloat(m_object_max_z) * GLfloat(this->get_cursor_z_relative(canvas))));
        glsafe(::glUniform1f(z_cursor_band_width_id, GLfloat(this->band_width)));
        // Initialize the layer height texture mapping.
        GLsizei w = (GLsizei)m_layers_texture.width;
        GLsizei h = (GLsizei)m_layers_texture.height;
        GLsizei half_w = w / 2;
        GLsizei half_h = h / 2;
        glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
        glsafe(::glBindTexture(GL_TEXTURE_2D, m_z_texture_id));
        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
        glsafe(::glTexImage2D(GL_TEXTURE_2D, 1, GL_RGBA, half_w, half_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
        glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data()));
        glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 1, 0, 0, half_w, half_h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data() + m_layers_texture.width * m_layers_texture.height * 4));
        for (const GLVolume *glvolume : volumes.volumes) {
            // Render the object using the layer editing shader and texture.
            if (! glvolume->is_active || glvolume->composite_id.object_id != this->last_object_id || glvolume->is_modifier)
                continue;
            if (world_matrix_id != -1)
                glsafe(::glUniformMatrix4fv(world_matrix_id, 1, GL_FALSE, (const GLfloat*)glvolume->world_matrix().cast<float>().data()));
            if (object_max_z_id != -1)
                glsafe(::glUniform1f(object_max_z_id, GLfloat(0)));
            glvolume->render();
        }
        // Revert back to the previous shader.
        glBindTexture(GL_TEXTURE_2D, 0);
        if (current_program_id > 0)
            glsafe(::glUseProgram(current_program_id));
    } 
    else 
    {
        // Something went wrong. Just render the object.
        assert(false);
		for (const GLVolume *glvolume : volumes.volumes) {
			// Render the object using the layer editing shader and texture.
			if (!glvolume->is_active || glvolume->composite_id.object_id != this->last_object_id || glvolume->is_modifier)
				continue;
            glsafe(::glUniformMatrix4fv(world_matrix_id, 1, GL_FALSE, (const GLfloat*)glvolume->world_matrix().cast<float>().data()));
			glvolume->render();
		}
	}
}

void GLCanvas3D::LayersEditing::adjust_layer_height_profile()
{
	this->update_slicing_parameters();
	PrintObject::update_layer_height_profile(*m_model_object, *m_slicing_parameters, m_layer_height_profile);
	Slic3r::adjust_layer_height_profile(*m_slicing_parameters, m_layer_height_profile, this->last_z, this->strength, this->band_width, this->last_action);
	m_layer_height_profile_modified = true;
    m_layers_texture.valid = false;
}

void GLCanvas3D::LayersEditing::reset_layer_height_profile(GLCanvas3D& canvas)
{
	const_cast<ModelObject*>(m_model_object)->layer_height_profile.clear();
    m_layer_height_profile.clear();
    m_layers_texture.valid = false;
    canvas.post_event(SimpleEvent(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS));
}

void GLCanvas3D::LayersEditing::generate_layer_height_texture()
{
	this->update_slicing_parameters();
	// Always try to update the layer height profile.
    bool update = ! m_layers_texture.valid;
    if (PrintObject::update_layer_height_profile(*m_model_object, *m_slicing_parameters, m_layer_height_profile)) {
        // Initialized to the default value.
        m_layer_height_profile_modified = false;
        update = true;
    }
    // Update if the layer height profile was changed, or when the texture is not valid.
    if (! update && ! m_layers_texture.data.empty() && m_layers_texture.cells > 0)
        // Texture is valid, don't update.
        return; 

    if (m_layers_texture.data.empty()) {
        m_layers_texture.width  = 1024;
        m_layers_texture.height = 1024;
        m_layers_texture.levels = 2;
        m_layers_texture.data.assign(m_layers_texture.width * m_layers_texture.height * 5, 0);
    }

    bool level_of_detail_2nd_level = true;
    m_layers_texture.cells = Slic3r::generate_layer_height_texture(
        *m_slicing_parameters, 
        Slic3r::generate_object_layers(*m_slicing_parameters, m_layer_height_profile), 
		m_layers_texture.data.data(), m_layers_texture.height, m_layers_texture.width, level_of_detail_2nd_level);
	m_layers_texture.valid = true;
}

void GLCanvas3D::LayersEditing::accept_changes(GLCanvas3D& canvas)
{
    if (last_object_id >= 0) {
        if (m_layer_height_profile_modified) {
            const_cast<ModelObject*>(m_model_object)->layer_height_profile = m_layer_height_profile;
			canvas.post_event(SimpleEvent(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS));
        }
    }
    m_layer_height_profile_modified = false;
}

void GLCanvas3D::LayersEditing::update_slicing_parameters()
{
	if (m_slicing_parameters == nullptr) {
		m_slicing_parameters = new SlicingParameters();
    	*m_slicing_parameters = PrintObject::slicing_parameters(*m_config, *m_model_object, m_object_max_z);
    }
}

float GLCanvas3D::LayersEditing::thickness_bar_width(const GLCanvas3D &canvas)
{
    return
#if ENABLE_RETINA_GL
        canvas.get_canvas_size().get_scale_factor()
#else
        canvas.get_wxglcanvas()->GetContentScaleFactor()
#endif
         * THICKNESS_BAR_WIDTH;
}

float GLCanvas3D::LayersEditing::reset_button_height(const GLCanvas3D &canvas)
{
    return
#if ENABLE_RETINA_GL
        canvas.get_canvas_size().get_scale_factor()
#else
        canvas.get_wxglcanvas()->GetContentScaleFactor()
#endif
         * THICKNESS_RESET_BUTTON_HEIGHT;
}


const Point GLCanvas3D::Mouse::Drag::Invalid_2D_Point(INT_MAX, INT_MAX);
const Vec3d GLCanvas3D::Mouse::Drag::Invalid_3D_Point(DBL_MAX, DBL_MAX, DBL_MAX);
const int GLCanvas3D::Mouse::Drag::MoveThresholdPx = 5;

GLCanvas3D::Mouse::Drag::Drag()
    : start_position_2D(Invalid_2D_Point)
    , start_position_3D(Invalid_3D_Point)
    , move_volume_idx(-1)
    , move_requires_threshold(false)
    , move_start_threshold_position_2D(Invalid_2D_Point)
{
}

GLCanvas3D::Mouse::Mouse()
    : dragging(false)
    , position(DBL_MAX, DBL_MAX)
    , scene_position(DBL_MAX, DBL_MAX, DBL_MAX)
    , ignore_left_up(false)
{
}

const unsigned char GLCanvas3D::WarningTexture::Background_Color[3] = { 120, 120, 120 };//{ 9, 91, 134 };
const unsigned char GLCanvas3D::WarningTexture::Opacity = 255;

GLCanvas3D::WarningTexture::WarningTexture()
    : GUI::GLTexture()
    , m_original_width(0)
    , m_original_height(0)
{
}

void GLCanvas3D::WarningTexture::activate(WarningTexture::Warning warning, bool state, const GLCanvas3D& canvas)
{
    auto it = std::find(m_warnings.begin(), m_warnings.end(), warning);

    if (state) {
        if (it != m_warnings.end()) // this warning is already set to be shown
            return;

        m_warnings.push_back(warning);
        std::sort(m_warnings.begin(), m_warnings.end());
    }
    else {
        if (it == m_warnings.end()) // deactivating something that is not active is an easy task
            return;

        m_warnings.erase(it);
        if (m_warnings.empty()) { // nothing remains to be shown
            reset();
            m_msg_text = "";// save information for rescaling
            return;
        }
    }

    // Look at the end of our vector and generate proper texture.
    std::string text;
    bool red_colored = false;
    switch (m_warnings.back()) {
        case ObjectOutside      : text = L("An object outside the print area was detected"); break;
        case ToolpathOutside    : text = L("A toolpath outside the print area was detected"); break;
        case SlaSupportsOutside : text = L("SLA supports outside the print area were detected"); break;
        case SomethingNotShown  : text = L("Some objects are not visible when editing supports"); break;
        case ObjectClashed: {
            text = L("An object outside the print area was detected\n"
                     "Resolve the current problem to continue slicing");
            red_colored = true;
            break;
        }
    }

    generate(text, canvas, true, red_colored); // GUI::GLTexture::reset() is called at the beginning of generate(...)

    // save information for rescaling
    m_msg_text = text;
    m_is_colored_red = red_colored;
}


#ifdef __WXMSW__
static bool is_font_cleartype(const wxFont &font)
{
    // Native font description: on MSW, it is a version number plus the content of LOGFONT, separated by semicolon.
    wxString font_desc = font.GetNativeFontInfoDesc();
    // Find the quality field.
    wxString sep(";");
    size_t startpos = 0;
    for (size_t i = 0; i < 12; ++ i)
        startpos = font_desc.find(sep, startpos + 1);
    ++ startpos;
    size_t endpos = font_desc.find(sep, startpos);
    int quality = wxAtoi(font_desc(startpos, endpos - startpos));
    return quality == CLEARTYPE_QUALITY;
}

// ClearType produces renders, which are difficult to convert into an alpha blended OpenGL texture.
// Therefore it is better to disable it, though Vojtech found out, that the font returned with ClearType
// disabled is signifcantly thicker than the default ClearType font.
// This function modifies the font provided.
static void msw_disable_cleartype(wxFont &font)
{
    // Native font description: on MSW, it is a version number plus the content of LOGFONT, separated by semicolon.
    wxString font_desc = font.GetNativeFontInfoDesc();
    // Find the quality field.
    wxString sep(";");
    size_t startpos_weight = 0;
    for (size_t i = 0; i < 5; ++ i)
        startpos_weight = font_desc.find(sep, startpos_weight + 1);
    ++ startpos_weight;
    size_t endpos_weight = font_desc.find(sep, startpos_weight);
    // Parse the weight field.
    unsigned int weight = atoi(font_desc(startpos_weight, endpos_weight - startpos_weight));
    size_t startpos = endpos_weight;
    for (size_t i = 0; i < 6; ++ i)
        startpos = font_desc.find(sep, startpos + 1);
    ++ startpos;
    size_t endpos = font_desc.find(sep, startpos);
    int quality = wxAtoi(font_desc(startpos, endpos - startpos));
    if (quality == CLEARTYPE_QUALITY) {
        // Replace the weight with a smaller value to compensate the weight of non ClearType font.
        wxString sweight    = std::to_string(weight * 2 / 4);
        size_t   len_weight = endpos_weight - startpos_weight;
        wxString squality   = std::to_string(ANTIALIASED_QUALITY);
        font_desc.replace(startpos_weight, len_weight, sweight);
        font_desc.replace(startpos + sweight.size() - len_weight, endpos - startpos, squality);
        font.SetNativeFontInfo(font_desc);
        wxString font_desc2 = font.GetNativeFontInfoDesc();
    }
    wxString font_desc2 = font.GetNativeFontInfoDesc();
}
#endif /* __WXMSW__ */

bool GLCanvas3D::WarningTexture::generate(const std::string& msg_utf8, const GLCanvas3D& canvas, bool compress, bool red_colored/* = false*/)
{
    reset();

    if (msg_utf8.empty())
        return false;

    wxString msg = _(msg_utf8);

    wxMemoryDC memDC;

#ifdef __WXMSW__
    // set scaled application normal font as default font 
    wxFont font = wxGetApp().normal_font();
#else
    // select default font
    const float scale = canvas.get_canvas_size().get_scale_factor();
    wxFont font = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT).Scale(scale);
#endif

    font.MakeLarger();
    font.MakeBold();
    memDC.SetFont(font);

    // calculates texture size
    wxCoord w, h;
    memDC.GetMultiLineTextExtent(msg, &w, &h);

    m_original_width = (int)w;
    m_original_height = (int)h;
    m_width = (int)next_highest_power_of_2((uint32_t)w);
	m_height = (int)next_highest_power_of_2((uint32_t)h);

    // generates bitmap
    wxBitmap bitmap(m_width, m_height);

    memDC.SelectObject(bitmap);
    memDC.SetBackground(wxBrush(*wxBLACK));
    memDC.Clear();

    // draw message
    memDC.SetTextForeground(*wxRED);
	memDC.DrawLabel(msg, wxRect(0,0, m_original_width, m_original_height), wxALIGN_CENTER);

    memDC.SelectObject(wxNullBitmap);

    // Convert the bitmap into a linear data ready to be loaded into the GPU.
    wxImage image = bitmap.ConvertToImage();

    // prepare buffer
    std::vector<unsigned char> data(4 * m_width * m_height, 0);
    const unsigned char *src = image.GetData();
    for (int h = 0; h < m_height; ++h)
    {
        unsigned char* dst = data.data() + 4 * h * m_width;
        for (int w = 0; w < m_width; ++w)
        {
            *dst++ = 255;
            if (red_colored) {
                *dst++ = 72; // 204
                *dst++ = 65; // 204
            } else {
                *dst++ = 255;
                *dst++ = 255;
            }
			*dst++ = (unsigned char)std::min<int>(255, *src);
            src += 3;
        }
    }

    // sends buffer to gpu
    glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
    glsafe(::glGenTextures(1, &m_id));
    glsafe(::glBindTexture(GL_TEXTURE_2D, (GLuint)m_id));
    if (compress && GLEW_EXT_texture_compression_s3tc)
        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, (GLsizei)m_width, (GLsizei)m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (const void*)data.data()));
    else
        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)m_width, (GLsizei)m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (const void*)data.data()));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0));
    glsafe(::glBindTexture(GL_TEXTURE_2D, 0));

    return true;
}

void GLCanvas3D::WarningTexture::render(const GLCanvas3D& canvas) const
{
    if (m_warnings.empty())
        return;

    if ((m_id > 0) && (m_original_width > 0) && (m_original_height > 0) && (m_width > 0) && (m_height > 0))
    {
        const Size& cnv_size = canvas.get_canvas_size();
        float zoom = (float)canvas.get_camera().get_zoom();
        float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
        float left = (-0.5f * (float)m_original_width) * inv_zoom;
        float top = (-0.5f * (float)cnv_size.get_height() + (float)m_original_height + 2.0f) * inv_zoom;
        float right = left + (float)m_original_width * inv_zoom;
        float bottom = top - (float)m_original_height * inv_zoom;

        float uv_left = 0.0f;
        float uv_top = 0.0f;
        float uv_right = (float)m_original_width / (float)m_width;
        float uv_bottom = (float)m_original_height / (float)m_height;

        GLTexture::Quad_UVs uvs;
        uvs.left_top = { uv_left, uv_top };
        uvs.left_bottom = { uv_left, uv_bottom };
        uvs.right_bottom = { uv_right, uv_bottom };
        uvs.right_top = { uv_right, uv_top };

        GLTexture::render_sub_texture(m_id, left, right, bottom, top, uvs);
    }
}

void GLCanvas3D::WarningTexture::msw_rescale(const GLCanvas3D& canvas)
{
    if (m_msg_text.empty())
        return;

    generate(m_msg_text, canvas, true, m_is_colored_red);
}

const unsigned char GLCanvas3D::LegendTexture::Squares_Border_Color[3] = { 64, 64, 64 };
const unsigned char GLCanvas3D::LegendTexture::Default_Background_Color[3] = { (unsigned char)(DEFAULT_BG_LIGHT_COLOR[0] * 255.0f), (unsigned char)(DEFAULT_BG_LIGHT_COLOR[1] * 255.0f), (unsigned char)(DEFAULT_BG_LIGHT_COLOR[2] * 255.0f) };
const unsigned char GLCanvas3D::LegendTexture::Error_Background_Color[3] = { (unsigned char)(ERROR_BG_LIGHT_COLOR[0] * 255.0f), (unsigned char)(ERROR_BG_LIGHT_COLOR[1] * 255.0f), (unsigned char)(ERROR_BG_LIGHT_COLOR[2] * 255.0f) };
const unsigned char GLCanvas3D::LegendTexture::Opacity = 255;

GLCanvas3D::LegendTexture::LegendTexture()
    : GUI::GLTexture()
    , m_original_width(0)
    , m_original_height(0)
{
}

void GLCanvas3D::LegendTexture::fill_color_print_legend_values(const GCodePreviewData& preview_data, const GLCanvas3D& canvas, 
                                                               std::vector<std::pair<double, double>>& cp_legend_values)
{
    if (preview_data.extrusion.view_type == GCodePreviewData::Extrusion::ColorPrint && 
        wxGetApp().extruders_edited_cnt() == 1) // show color change legend only for single-material presets
    {
        auto& config = wxGetApp().preset_bundle->project_config;
        const std::vector<double>& color_print_values = config.option<ConfigOptionFloats>("colorprint_heights")->values;
        const int values_cnt = color_print_values.size();
        if (values_cnt > 0) {
            auto print_zs = canvas.get_current_print_zs(true);
            auto z = 0;
            for (auto i = 0; i < values_cnt; ++i)
            {
                double prev_z = -1.0;
                for (z; z < print_zs.size(); ++z)
                    if (fabs(color_print_values[i] - print_zs[z]) < EPSILON) {
                        prev_z = print_zs[z - 1];
                        break;
                    }
                if (prev_z < 0)
                    continue;
                
                cp_legend_values.push_back(std::pair<double, double>(prev_z, color_print_values[i]));
            }
        }
    }
}

bool GLCanvas3D::LegendTexture::generate(const GCodePreviewData& preview_data, const std::vector<float>& tool_colors, const GLCanvas3D& canvas, bool compress)
{
    reset();

    // collects items to render
    auto title = _(preview_data.get_legend_title());

    std::vector<std::pair<double, double>> cp_legend_values;
    fill_color_print_legend_values(preview_data, canvas, cp_legend_values);

    const GCodePreviewData::LegendItemsList& items = preview_data.get_legend_items(tool_colors, cp_legend_values);

    unsigned int items_count = (unsigned int)items.size();
    if (items_count == 0)
        // nothing to render, return
        return false;

    wxMemoryDC memDC;
    wxMemoryDC mask_memDC;

    // calculate scaling
    const float scale_gl = canvas.get_canvas_size().get_scale_factor();
    const float scale = scale_gl * wxGetApp().em_unit()*0.1; // get scale from em_unit() value, because of get_scale_factor() return 1 
    const int scaled_square = std::floor((float)Px_Square * scale);
    const int scaled_title_offset = Px_Title_Offset * scale;
    const int scaled_text_offset = Px_Text_Offset * scale;
    const int scaled_square_contour = Px_Square_Contour * scale;
    const int scaled_border = Px_Border * scale;

#ifdef __WXMSW__
    // set scaled application normal font as default font 
    wxFont font = wxGetApp().normal_font();

    // Disabling ClearType works, but the font returned is very different (much thicker) from the default.
//    msw_disable_cleartype(font);
    bool cleartype = is_font_cleartype(font);
#else
    // select default font
    wxFont font = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT).Scale(scale_gl);
    bool cleartype = false;
#endif /* __WXMSW__ */

    memDC.SetFont(font);
    mask_memDC.SetFont(font);

    // calculates texture size
    wxCoord w, h;
    memDC.GetTextExtent(title, &w, &h);
    int title_width = (int)w;
    int title_height = (int)h;

    int max_text_width = 0;
    int max_text_height = 0;
    for (const GCodePreviewData::LegendItem& item : items)
    {
        memDC.GetTextExtent(GUI::from_u8(item.text), &w, &h);
        max_text_width = std::max(max_text_width, (int)w);
        max_text_height = std::max(max_text_height, (int)h);
    }

    m_original_width = std::max(2 * scaled_border + title_width, 2 * (scaled_border + scaled_square_contour) + scaled_square + scaled_text_offset + max_text_width);
    m_original_height = 2 * (scaled_border + scaled_square_contour) + title_height + scaled_title_offset + items_count * scaled_square;
    if (items_count > 1)
        m_original_height += (items_count - 1) * scaled_square_contour;

	m_width = (int)next_highest_power_of_2((uint32_t)m_original_width);
	m_height = (int)next_highest_power_of_2((uint32_t)m_original_height);

    // generates bitmap
    wxBitmap bitmap(m_width, m_height);
    wxBitmap mask(m_width, m_height);

    memDC.SelectObject(bitmap);
    mask_memDC.SelectObject(mask);

    memDC.SetBackground(wxBrush(*wxBLACK));
    mask_memDC.SetBackground(wxBrush(*wxBLACK));

    memDC.Clear();
    mask_memDC.Clear();

    // draw title
    memDC.SetTextForeground(*wxWHITE);
	mask_memDC.SetTextForeground(*wxRED);

    int title_x = scaled_border;
    int title_y = scaled_border;
    memDC.DrawText(title, title_x, title_y);
    mask_memDC.DrawText(title, title_x, title_y);

    // draw icons contours as background
    int squares_contour_x = scaled_border;
    int squares_contour_y = scaled_border + title_height + scaled_title_offset;
    int squares_contour_width = scaled_square + 2 * scaled_square_contour;
    int squares_contour_height = items_count * scaled_square + 2 * scaled_square_contour;
    if (items_count > 1)
        squares_contour_height += (items_count - 1) * scaled_square_contour;

    wxColour color(Squares_Border_Color[0], Squares_Border_Color[1], Squares_Border_Color[2]);
    wxPen pen(color);
    wxBrush brush(color);
    memDC.SetPen(pen);
    memDC.SetBrush(brush);
    memDC.DrawRectangle(wxRect(squares_contour_x, squares_contour_y, squares_contour_width, squares_contour_height));

    // draw items (colored icon + text)
    int icon_x = squares_contour_x + scaled_square_contour;
    int icon_x_inner = icon_x + 1;
    int icon_y = squares_contour_y + scaled_square_contour;
    int icon_y_step = scaled_square + scaled_square_contour;

    int text_x = icon_x + scaled_square + scaled_text_offset;
    int text_y_offset = (scaled_square - max_text_height) / 2;

    int px_inner_square = scaled_square - 2;

    for (const GCodePreviewData::LegendItem& item : items)
    {
        // draw darker icon perimeter
        const std::vector<unsigned char>& item_color_bytes = item.color.as_bytes();
        wxImage::HSVValue dark_hsv = wxImage::RGBtoHSV(wxImage::RGBValue(item_color_bytes[0], item_color_bytes[1], item_color_bytes[2]));
        dark_hsv.value *= 0.75;
        wxImage::RGBValue dark_rgb = wxImage::HSVtoRGB(dark_hsv);
        color.Set(dark_rgb.red, dark_rgb.green, dark_rgb.blue, item_color_bytes[3]);
        pen.SetColour(color);
        brush.SetColour(color);
        memDC.SetPen(pen);
        memDC.SetBrush(brush);
        memDC.DrawRectangle(wxRect(icon_x, icon_y, scaled_square, scaled_square));

        // draw icon interior
        color.Set(item_color_bytes[0], item_color_bytes[1], item_color_bytes[2], item_color_bytes[3]);
        pen.SetColour(color);
        brush.SetColour(color);
        memDC.SetPen(pen);
        memDC.SetBrush(brush);
        memDC.DrawRectangle(wxRect(icon_x_inner, icon_y + 1, px_inner_square, px_inner_square));

        // draw text
        mask_memDC.DrawText(GUI::from_u8(item.text), text_x, icon_y + text_y_offset);

        // update y
        icon_y += icon_y_step;
    }

    memDC.SelectObject(wxNullBitmap);
    mask_memDC.SelectObject(wxNullBitmap);

    // Convert the bitmap into a linear data ready to be loaded into the GPU.
    wxImage image = bitmap.ConvertToImage();
    wxImage mask_image = mask.ConvertToImage();

    // prepare buffer
    std::vector<unsigned char> data(4 * m_width * m_height, 0);
	const unsigned char *src_image = image.GetData();
    const unsigned char *src_mask  = mask_image.GetData();
	for (int h = 0; h < m_height; ++h)
    {
        int hh = h * m_width;
        unsigned char* px_ptr = data.data() + 4 * hh;
        for (int w = 0; w < m_width; ++w)
        {
			if (w >= squares_contour_x && w < squares_contour_x + squares_contour_width &&
				h >= squares_contour_y && h < squares_contour_y + squares_contour_height) {
				// Color palette, use the color verbatim.
				*px_ptr++ = *src_image++;
				*px_ptr++ = *src_image++;
				*px_ptr++ = *src_image++;
				*px_ptr++ = 255;
			} else {
				// Text or background
				unsigned char alpha = *src_mask;
				// Compensate the white color for the 50% opacity reduction at the character edges.
                //unsigned char color = (unsigned char)floor(alpha * 255.f / (128.f + 0.5f * alpha));
                unsigned char color = alpha;
				*px_ptr++ = color;
				*px_ptr++ = color; // *src_mask ++;
				*px_ptr++ = color; // *src_mask ++;
				*px_ptr++ = 128 + (alpha / 2); // (alpha > 0) ? 255 : 128;
				src_image += 3;
			}
            src_mask += 3;
        }
    }

    // sends buffer to gpu
    glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
    glsafe(::glGenTextures(1, &m_id));
    glsafe(::glBindTexture(GL_TEXTURE_2D, (GLuint)m_id));
    if (compress && GLEW_EXT_texture_compression_s3tc)
        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, (GLsizei)m_width, (GLsizei)m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (const void*)data.data()));
    else
        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)m_width, (GLsizei)m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (const void*)data.data()));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
    glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0));
    glsafe(::glBindTexture(GL_TEXTURE_2D, 0));

    return true;
}

void GLCanvas3D::LegendTexture::render(const GLCanvas3D& canvas) const
{
    if ((m_id > 0) && (m_original_width > 0) && (m_original_height > 0) && (m_width > 0) && (m_height > 0))
    {
        const Size& cnv_size = canvas.get_canvas_size();
        float zoom = (float)canvas.get_camera().get_zoom();
        float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
        float left = (-0.5f * (float)cnv_size.get_width()) * inv_zoom;
        float top = (0.5f * (float)cnv_size.get_height()) * inv_zoom;
        float right = left + (float)m_original_width * inv_zoom;
        float bottom = top - (float)m_original_height * inv_zoom;

        float uv_left = 0.0f;
        float uv_top = 0.0f;
        float uv_right = (float)m_original_width / (float)m_width;
        float uv_bottom = (float)m_original_height / (float)m_height;

        GLTexture::Quad_UVs uvs;
        uvs.left_top = { uv_left, uv_top };
        uvs.left_bottom = { uv_left, uv_bottom };
        uvs.right_bottom = { uv_right, uv_bottom };
        uvs.right_top = { uv_right, uv_top };

        GLTexture::render_sub_texture(m_id, left, right, bottom, top, uvs);
    }
}

wxDEFINE_EVENT(EVT_GLCANVAS_INIT, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_OBJECT_SELECT, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_RIGHT_CLICK, Vec2dEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_REMOVE_OBJECT, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_ARRANGE, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_SELECT_ALL, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_QUESTION_MARK, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_INCREASE_INSTANCES, Event<int>);
wxDEFINE_EVENT(EVT_GLCANVAS_INSTANCE_MOVED, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_INSTANCE_ROTATED, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_INSTANCE_SCALED, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_WIPETOWER_MOVED, Vec3dEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_WIPETOWER_ROTATED, Vec3dEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_ENABLE_ACTION_BUTTONS, Event<bool>);
wxDEFINE_EVENT(EVT_GLCANVAS_UPDATE_GEOMETRY, Vec3dsEvent<2>);
wxDEFINE_EVENT(EVT_GLCANVAS_MOUSE_DRAGGING_FINISHED, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_UPDATE_BED_SHAPE, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_TAB, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_RESETGIZMOS, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_MOVE_DOUBLE_SLIDER, wxKeyEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_EDIT_COLOR_CHANGE, wxKeyEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_UNDO, SimpleEvent);
wxDEFINE_EVENT(EVT_GLCANVAS_REDO, SimpleEvent);

GLCanvas3D::GLCanvas3D(wxGLCanvas* canvas, Bed3D& bed, Camera& camera, GLToolbar& view_toolbar)
    : m_canvas(canvas)
    , m_context(nullptr)
#if ENABLE_RETINA_GL
    , m_retina_helper(nullptr)
#endif
    , m_in_render(false)
    , m_bed(bed)
    , m_camera(camera)
    , m_view_toolbar(view_toolbar)
#if ENABLE_SVG_ICONS
    , m_toolbar(GLToolbar::Normal, "Top")
#else
    , m_toolbar(GLToolbar::Normal)
#endif // ENABLE_SVG_ICONS
    , m_use_clipping_planes(false)
    , m_sidebar_field("")
    , m_keep_dirty(false)
    , m_config(nullptr)
    , m_process(nullptr)
    , m_model(nullptr)
    , m_dirty(true)
    , m_initialized(false)
    , m_use_VBOs(false)
    , m_apply_zoom_to_volumes_filter(false)
    , m_legend_texture_enabled(false)
    , m_picking_enabled(false)
    , m_moving_enabled(false)
    , m_dynamic_background_enabled(false)
    , m_multisample_allowed(false)
    , m_regenerate_volumes(true)
    , m_moving(false)
    , m_tab_down(false)
    , m_cursor_type(Standard)
    , m_color_by("volume")
    , m_reload_delayed(false)
#if ENABLE_RENDER_PICKING_PASS
    , m_show_picking_texture(false)
#endif // ENABLE_RENDER_PICKING_PASS
    , m_render_sla_auxiliaries(true)
{
    if (m_canvas != nullptr) {
        m_timer.SetOwner(m_canvas);
#if ENABLE_RETINA_GL
        m_retina_helper.reset(new RetinaHelper(canvas));
        // set default view_toolbar icons size equal to GLGizmosManager::Default_Icons_Size
        m_view_toolbar.set_icons_size(GLGizmosManager::Default_Icons_Size);
#endif
    }

    m_selection.set_volumes(&m_volumes.volumes);
}

GLCanvas3D::~GLCanvas3D()
{
    reset_volumes();
}

void GLCanvas3D::post_event(wxEvent &&event)
{
    event.SetEventObject(m_canvas);
    wxPostEvent(m_canvas, event);
}

bool GLCanvas3D::init(bool useVBOs)
{
    if (m_initialized)
        return true;

    if ((m_canvas == nullptr) || (m_context == nullptr))
        return false;

    glsafe(::glClearColor(1.0f, 1.0f, 1.0f, 1.0f));
    glsafe(::glClearDepth(1.0f));

    glsafe(::glDepthFunc(GL_LESS));

    glsafe(::glEnable(GL_DEPTH_TEST));
    glsafe(::glEnable(GL_CULL_FACE));
    glsafe(::glEnable(GL_BLEND));
    glsafe(::glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));

    // Set antialiasing / multisampling
    glsafe(::glDisable(GL_LINE_SMOOTH));
    glsafe(::glDisable(GL_POLYGON_SMOOTH));

    // ambient lighting
    GLfloat ambient[4] = { 0.3f, 0.3f, 0.3f, 1.0f };
    glsafe(::glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambient));

    glsafe(::glEnable(GL_LIGHT0));
    glsafe(::glEnable(GL_LIGHT1));

    // light from camera
    GLfloat specular_cam[4] = { 0.3f, 0.3f, 0.3f, 1.0f };
    glsafe(::glLightfv(GL_LIGHT1, GL_SPECULAR, specular_cam));
    GLfloat diffuse_cam[4] = { 0.2f, 0.2f, 0.2f, 1.0f };
    glsafe(::glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse_cam));

    // light from above
    GLfloat specular_top[4] = { 0.2f, 0.2f, 0.2f, 1.0f };
    glsafe(::glLightfv(GL_LIGHT0, GL_SPECULAR, specular_top));
    GLfloat diffuse_top[4] = { 0.5f, 0.5f, 0.5f, 1.0f };
    glsafe(::glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse_top));

    // Enables Smooth Color Shading; try GL_FLAT for (lack of) fun.
    glsafe(::glShadeModel(GL_SMOOTH));

    // A handy trick -- have surface material mirror the color.
    glsafe(::glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE));
    glsafe(::glEnable(GL_COLOR_MATERIAL));

    if (m_multisample_allowed)
        glsafe(::glEnable(GL_MULTISAMPLE));

    if (useVBOs && !m_shader.init("gouraud.vs", "gouraud.fs"))
        return false;

    if (m_toolbar.is_enabled() && useVBOs && !m_layers_editing.init("variable_layer_height.vs", "variable_layer_height.fs"))
        return false;

    m_use_VBOs = useVBOs;

    // on linux the gl context is not valid until the canvas is not shown on screen
    // we defer the geometry finalization of volumes until the first call to render()
    if (!m_volumes.empty())
        m_volumes.finalize_geometry(m_use_VBOs);

    if (m_gizmos.is_enabled()) {
        if (! m_gizmos.init(*this)) { 
            std::cout << "Unable to initialize gizmos: please, check that all the required textures are available" << std::endl;
            return false;
        }
    }

    if (!_init_toolbar())
        return false;

    if (m_selection.is_enabled() && !m_selection.init(m_use_VBOs))
        return false;

    post_event(SimpleEvent(EVT_GLCANVAS_INIT));

    m_initialized = true;

    return true;
}

void GLCanvas3D::set_as_dirty()
{
    m_dirty = true;
}

unsigned int GLCanvas3D::get_volumes_count() const
{
    return (unsigned int)m_volumes.volumes.size();
}

void GLCanvas3D::reset_volumes()
{
    if (!m_initialized)
        return;

    _set_current();

    if (!m_volumes.empty())
    {
        m_selection.clear();
        m_volumes.release_geometry();
        m_volumes.clear();
        m_dirty = true;
    }

    _set_warning_texture(WarningTexture::ObjectOutside, false);
}

int GLCanvas3D::check_volumes_outside_state() const
{
    ModelInstance::EPrintVolumeState state;
    m_volumes.check_outside_state(m_config, &state);
    return (int)state;
}

void GLCanvas3D::toggle_sla_auxiliaries_visibility(bool visible, const ModelObject* mo, int instance_idx)
{
    for (GLVolume* vol : m_volumes.volumes) {
        if ((mo == nullptr || m_model->objects[vol->composite_id.object_id] == mo)
        && (instance_idx == -1 || vol->composite_id.instance_id == instance_idx)
        && vol->composite_id.volume_id < 0)
            vol->is_active = visible;
    }

    m_render_sla_auxiliaries = visible;
}

void GLCanvas3D::toggle_model_objects_visibility(bool visible, const ModelObject* mo, int instance_idx)
{
    for (GLVolume* vol : m_volumes.volumes) {
        if ((mo == nullptr || m_model->objects[vol->composite_id.object_id] == mo)
        && (instance_idx == -1 || vol->composite_id.instance_id == instance_idx)) {
            vol->is_active = visible;
            vol->force_native_color = (instance_idx != -1);
        }
    }
    if (visible && !mo)
        toggle_sla_auxiliaries_visibility(true, mo, instance_idx);

    if (!mo && !visible && !m_model->objects.empty() && (m_model->objects.size() > 1 || m_model->objects.front()->instances.size() > 1))
        _set_warning_texture(WarningTexture::SomethingNotShown, true);

    if (!mo && visible)
        _set_warning_texture(WarningTexture::SomethingNotShown, false);
}


void GLCanvas3D::set_config(const DynamicPrintConfig* config)
{
    m_config = config;
    m_layers_editing.set_config(config);
}

void GLCanvas3D::set_process(BackgroundSlicingProcess *process)
{
    m_process = process;
}

void GLCanvas3D::set_model(Model* model)
{
    m_model = model;
    m_selection.set_model(m_model);
}

void GLCanvas3D::bed_shape_changed()
{
    m_camera.set_scene_box(scene_bounding_box());
    m_camera.requires_zoom_to_bed = true;
    m_dirty = true;
    if (m_bed.is_prusa())
        start_keeping_dirty();
}

void GLCanvas3D::set_color_by(const std::string& value)
{
    m_color_by = value;
}

BoundingBoxf3 GLCanvas3D::volumes_bounding_box() const
{
    BoundingBoxf3 bb;
    for (const GLVolume* volume : m_volumes.volumes)
    {
        if (!m_apply_zoom_to_volumes_filter || ((volume != nullptr) && volume->zoom_to_volumes))
            bb.merge(volume->transformed_bounding_box());
    }
    return bb;
}

BoundingBoxf3 GLCanvas3D::scene_bounding_box() const
{
    BoundingBoxf3 bb = volumes_bounding_box();
    bb.merge(m_bed.get_bounding_box(false));

    if (m_config != nullptr)
    {
        double h = m_config->opt_float("max_print_height");
        bb.min(2) = std::min(bb.min(2), -h);
        bb.max(2) = std::max(bb.max(2), h);
    }

    return bb;
}

bool GLCanvas3D::is_layers_editing_enabled() const
{
    return m_layers_editing.is_enabled();
}

bool GLCanvas3D::is_layers_editing_allowed() const
{
    return m_layers_editing.is_allowed();
}

bool GLCanvas3D::is_reload_delayed() const
{
    return m_reload_delayed;
}

void GLCanvas3D::enable_layers_editing(bool enable)
{
    m_layers_editing.set_enabled(enable);
    const Selection::IndicesList& idxs = m_selection.get_volume_idxs();
    for (unsigned int idx : idxs)
    {
        GLVolume* v = m_volumes.volumes[idx];
        if (v->is_modifier)
            v->force_transparent = enable;
    }

    set_as_dirty();
}

void GLCanvas3D::enable_legend_texture(bool enable)
{
    m_legend_texture_enabled = enable;
}

void GLCanvas3D::enable_picking(bool enable)
{
    m_picking_enabled = enable;
    m_selection.set_mode(Selection::Instance);
}

void GLCanvas3D::enable_moving(bool enable)
{
    m_moving_enabled = enable;
}

void GLCanvas3D::enable_gizmos(bool enable)
{
    m_gizmos.set_enabled(enable);
}

void GLCanvas3D::enable_selection(bool enable)
{
    m_selection.set_enabled(enable);
}

void GLCanvas3D::enable_toolbar(bool enable)
{
    m_toolbar.set_enabled(enable);
}

void GLCanvas3D::enable_dynamic_background(bool enable)
{
    m_dynamic_background_enabled = enable;
}

void GLCanvas3D::allow_multisample(bool allow)
{
    m_multisample_allowed = allow;
}

void GLCanvas3D::zoom_to_bed()
{
    _zoom_to_box(m_bed.get_bounding_box(false));
}

void GLCanvas3D::zoom_to_volumes()
{
    m_apply_zoom_to_volumes_filter = true;
    _zoom_to_box(volumes_bounding_box());
    m_apply_zoom_to_volumes_filter = false;
}

void GLCanvas3D::zoom_to_selection()
{
    if (!m_selection.is_empty())
        _zoom_to_box(m_selection.get_bounding_box());
}

void GLCanvas3D::select_view(const std::string& direction)
{
    if (m_camera.select_view(direction) && (m_canvas != nullptr))
        m_canvas->Refresh();
}

void GLCanvas3D::update_volumes_colors_by_extruder()
{
    if (m_config != nullptr)
        m_volumes.update_colors_by_extruder(m_config);
}

void GLCanvas3D::render()
{
    if (m_in_render)
    {
        // if called recursively, return
        m_dirty = true;
        return;
    }

    m_in_render = true;
    Slic3r::ScopeGuard in_render_guard([this]() { m_in_render = false; });
    (void)in_render_guard;

    if (m_canvas == nullptr)
        return;

#ifndef __WXMAC__
    // on Mac this check causes flickering when changing view
    if (!_is_shown_on_screen())
        return;
#endif // __WXMAC__

    // ensures this canvas is current and initialized
    if (!_set_current() || !_3DScene::init(m_canvas))
        return;

#if ENABLE_RENDER_STATISTICS
    auto start_time = std::chrono::high_resolution_clock::now();
#endif // ENABLE_RENDER_STATISTICS

    if (m_bed.get_shape().empty())
    {
        // this happens at startup when no data is still saved under <>\AppData\Roaming\Slic3rPE
        post_event(SimpleEvent(EVT_GLCANVAS_UPDATE_BED_SHAPE));
        return;
    }

    if (m_camera.requires_zoom_to_bed)
    {
        zoom_to_bed();
        const Size& cnv_size = get_canvas_size();
        _resize((unsigned int)cnv_size.get_width(), (unsigned int)cnv_size.get_height());
        m_camera.requires_zoom_to_bed = false;
    }

    m_camera.apply_view_matrix();
    m_camera.apply_projection(_max_bounding_box(true));

    GLfloat position_cam[4] = { 1.0f, 0.0f, 1.0f, 0.0f };
    glsafe(::glLightfv(GL_LIGHT1, GL_POSITION, position_cam));
    GLfloat position_top[4] = { -0.5f, -0.5f, 1.0f, 0.0f };
    glsafe(::glLightfv(GL_LIGHT0, GL_POSITION, position_top));

    float theta = m_camera.get_theta();
    if (theta > 180.f)
        // absolute value of the rotation
        theta = 360.f - theta;

    wxGetApp().imgui()->new_frame();

    if (m_picking_enabled)
    {
        if (m_rectangle_selection.is_dragging())
            // picking pass using rectangle selection
            _rectangular_selection_picking_pass();
        else
            // regular picking pass
            _picking_pass();
    }

#if ENABLE_RENDER_PICKING_PASS
    if (!m_picking_enabled || !m_show_picking_texture)
    {
#endif // ENABLE_RENDER_PICKING_PASS
    // draw scene
    glsafe(::glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));
    _render_background();

    // textured bed needs to be rendered after objects if the texture is transparent
    bool early_bed_render = m_bed.is_custom() || (theta <= 90.0f);
    if (early_bed_render)
        _render_bed(theta);

    _render_objects();
    _render_sla_slices();
    _render_selection();

    _render_axes();

    if (!early_bed_render)
        _render_bed(theta);

#if ENABLE_RENDER_SELECTION_CENTER
    _render_selection_center();
#endif // ENABLE_RENDER_SELECTION_CENTER

    // we need to set the mouse's scene position here because the depth buffer
    // could be invalidated by the following gizmo render methods
    // this position is used later into on_mouse() to drag the objects
    m_mouse.scene_position = _mouse_to_3d(m_mouse.position.cast<int>());

    _render_current_gizmo();
    _render_selection_sidebar_hints();
#if ENABLE_RENDER_PICKING_PASS
    }
#endif // ENABLE_RENDER_PICKING_PASS

#if ENABLE_SHOW_CAMERA_TARGET
    _render_camera_target();
#endif // ENABLE_SHOW_CAMERA_TARGET

    if (m_picking_enabled && m_rectangle_selection.is_dragging())
        m_rectangle_selection.render(*this);

    // draw overlays
    _render_overlays();

#if ENABLE_RENDER_STATISTICS
    ImGuiWrapper& imgui = *wxGetApp().imgui();
    imgui.set_next_window_bg_alpha(0.5f);
    imgui.begin(std::string("Render statistics"), ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse);
    imgui.text("Last frame: ");
    ImGui::SameLine();
    imgui.text(std::to_string(m_render_stats.last_frame));
    ImGui::SameLine();
    imgui.text("  ms");
    ImGui::Separator();
    imgui.text("Compressed textures: ");
    ImGui::SameLine();
    imgui.text(GLCanvas3DManager::are_compressed_textures_supported() ? "supported" : "not supported");
    imgui.text("Max texture size: ");
    ImGui::SameLine();
    imgui.text(std::to_string(GLCanvas3DManager::get_gl_info().get_max_tex_size()));
    imgui.end();
#endif // ENABLE_RENDER_STATISTICS

#if ENABLE_CAMERA_STATISTICS
    m_camera.debug_render();
#endif // ENABLE_CAMERA_STATISTICS

    wxGetApp().imgui()->render();

    m_canvas->SwapBuffers();

#if ENABLE_RENDER_STATISTICS
    auto end_time = std::chrono::high_resolution_clock::now();
    m_render_stats.last_frame = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time).count();
#endif // ENABLE_RENDER_STATISTICS
}

void GLCanvas3D::select_all()
{
    m_selection.add_all();
    m_dirty = true;
}

void GLCanvas3D::deselect_all()
{
    m_selection.clear();
    m_selection.set_mode(Selection::Instance);
    wxGetApp().obj_manipul()->set_dirty();
    m_gizmos.reset_all_states();
    m_gizmos.update_data(*this);
    post_event(SimpleEvent(EVT_GLCANVAS_OBJECT_SELECT));
}

void GLCanvas3D::delete_selected()
{
    m_selection.erase();
}

void GLCanvas3D::ensure_on_bed(unsigned int object_idx)
{
    typedef std::map<std::pair<int, int>, double> InstancesToZMap;
    InstancesToZMap instances_min_z;

    for (GLVolume* volume : m_volumes.volumes)
    {
        if ((volume->object_idx() == object_idx) && !volume->is_modifier)
        {
            double min_z = volume->transformed_convex_hull_bounding_box().min(2);
            std::pair<int, int> instance = std::make_pair(volume->object_idx(), volume->instance_idx());
            InstancesToZMap::iterator it = instances_min_z.find(instance);
            if (it == instances_min_z.end())
                it = instances_min_z.insert(InstancesToZMap::value_type(instance, DBL_MAX)).first;

            it->second = std::min(it->second, min_z);
        }
    }

    for (GLVolume* volume : m_volumes.volumes)
    {
        std::pair<int, int> instance = std::make_pair(volume->object_idx(), volume->instance_idx());
        InstancesToZMap::iterator it = instances_min_z.find(instance);
        if (it != instances_min_z.end())
            volume->set_instance_offset(Z, volume->get_instance_offset(Z) - it->second);
    }
}

std::vector<double> GLCanvas3D::get_current_print_zs(bool active_only) const
{
    return m_volumes.get_current_print_zs(active_only);
}

void GLCanvas3D::set_toolpaths_range(double low, double high)
{
    m_volumes.set_range(low, high);
}

std::vector<int> GLCanvas3D::load_object(const ModelObject& model_object, int obj_idx, std::vector<int> instance_idxs)
{
    if (instance_idxs.empty())
    {
        for (unsigned int i = 0; i < model_object.instances.size(); ++i)
        {
            instance_idxs.push_back(i);
        }
    }
    return m_volumes.load_object(&model_object, obj_idx, instance_idxs, m_color_by, m_use_VBOs && m_initialized);
}

std::vector<int> GLCanvas3D::load_object(const Model& model, int obj_idx)
{
    if ((0 <= obj_idx) && (obj_idx < (int)model.objects.size()))
    {
        const ModelObject* model_object = model.objects[obj_idx];
        if (model_object != nullptr)
            return load_object(*model_object, obj_idx, std::vector<int>());
    }

    return std::vector<int>();
}

void GLCanvas3D::mirror_selection(Axis axis)
{
    m_selection.mirror(axis);
    do_mirror("Mirror Object");
    wxGetApp().obj_manipul()->set_dirty();
}

// Reload the 3D scene of 
// 1) Model / ModelObjects / ModelInstances / ModelVolumes
// 2) Print bed
// 3) SLA support meshes for their respective ModelObjects / ModelInstances
// 4) Wipe tower preview
// 5) Out of bed collision status & message overlay (texture)
void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_refresh)
{
    if ((m_canvas == nullptr) || (m_config == nullptr) || (m_model == nullptr))
        return;

    if (m_initialized)
        _set_current();

    struct ModelVolumeState {
        ModelVolumeState(const GLVolume *volume) : 
			model_volume(nullptr), geometry_id(volume->geometry_id), volume_idx(-1) {}
		ModelVolumeState(const ModelVolume *model_volume, const ObjectID &instance_id, const GLVolume::CompositeID &composite_id) :
			model_volume(model_volume), geometry_id(std::make_pair(model_volume->id().id, instance_id.id)), composite_id(composite_id), volume_idx(-1) {}
		ModelVolumeState(const ObjectID &volume_id, const ObjectID &instance_id) :
			model_volume(nullptr), geometry_id(std::make_pair(volume_id.id, instance_id.id)), volume_idx(-1) {}
		bool new_geometry() const { return this->volume_idx == size_t(-1); }
		const ModelVolume		   *model_volume;
        // ObjectID of ModelVolume + ObjectID of ModelInstance
        // or timestamp of an SLAPrintObjectStep + ObjectID of ModelInstance
        std::pair<size_t, size_t>   geometry_id;
        GLVolume::CompositeID       composite_id;
        // Volume index in the new GLVolume vector.
		size_t                      volume_idx;
    };
    std::vector<ModelVolumeState> model_volume_state;
	std::vector<ModelVolumeState> aux_volume_state;

    // SLA steps to pull the preview meshes for.
	typedef std::array<SLAPrintObjectStep, 2> SLASteps;
	SLASteps sla_steps = { slaposSupportTree, slaposBasePool };
    struct SLASupportState {
		std::array<PrintStateBase::StateWithTimeStamp, std::tuple_size<SLASteps>::value> step;
    };
    // State of the sla_steps for all SLAPrintObjects.
    std::vector<SLASupportState>   sla_support_state;

    std::vector<size_t> instance_ids_selected;
    std::vector<size_t> map_glvolume_old_to_new(m_volumes.volumes.size(), size_t(-1));
    std::vector<GLVolume*> glvolumes_new;
    glvolumes_new.reserve(m_volumes.volumes.size());
    auto model_volume_state_lower = [](const ModelVolumeState &m1, const ModelVolumeState &m2) { return m1.geometry_id < m2.geometry_id; };

    m_reload_delayed = ! m_canvas->IsShown() && ! refresh_immediately && ! force_full_scene_refresh;

    PrinterTechnology printer_technology        = m_process->current_printer_technology();
    int               volume_idx_wipe_tower_old = -1;

    if (m_regenerate_volumes)
    {
        // Release invalidated volumes to conserve GPU memory in case of delayed refresh (see m_reload_delayed).
        // First initialize model_volumes_new_sorted & model_instances_new_sorted.
        for (int object_idx = 0; object_idx < (int)m_model->objects.size(); ++ object_idx) {
            const ModelObject *model_object = m_model->objects[object_idx];
            for (int instance_idx = 0; instance_idx < (int)model_object->instances.size(); ++ instance_idx) {
                const ModelInstance *model_instance = model_object->instances[instance_idx];
                for (int volume_idx = 0; volume_idx < (int)model_object->volumes.size(); ++ volume_idx) {
                    const ModelVolume *model_volume = model_object->volumes[volume_idx];
					model_volume_state.emplace_back(model_volume, model_instance->id(), GLVolume::CompositeID(object_idx, volume_idx, instance_idx));
                }
            }
        }
        if (printer_technology == ptSLA) {
            const SLAPrint *sla_print = this->sla_print();
		#ifndef NDEBUG
            // Verify that the SLAPrint object is synchronized with m_model.
            check_model_ids_equal(*m_model, sla_print->model());
        #endif /* NDEBUG */
            sla_support_state.reserve(sla_print->objects().size());
            for (const SLAPrintObject *print_object : sla_print->objects()) {
                SLASupportState state;
				for (size_t istep = 0; istep < sla_steps.size(); ++ istep) {
					state.step[istep] = print_object->step_state_with_timestamp(sla_steps[istep]);
					if (state.step[istep].state == PrintStateBase::DONE) {
                        if (! print_object->has_mesh(sla_steps[istep]))
                            // Consider the DONE step without a valid mesh as invalid for the purpose
                            // of mesh visualization.
                            state.step[istep].state = PrintStateBase::INVALID;
                        else
    						for (const ModelInstance *model_instance : print_object->model_object()->instances)
                                aux_volume_state.emplace_back(state.step[istep].timestamp, model_instance->id());
                    }
				}
				sla_support_state.emplace_back(state);
            }
        }
        std::sort(model_volume_state.begin(), model_volume_state.end(), model_volume_state_lower);
        std::sort(aux_volume_state  .begin(), aux_volume_state  .end(), model_volume_state_lower);
        // Release all ModelVolume based GLVolumes not found in the current Model.
        for (size_t volume_id = 0; volume_id < m_volumes.volumes.size(); ++ volume_id) {
            GLVolume         *volume = m_volumes.volumes[volume_id];
            ModelVolumeState  key(volume);
            ModelVolumeState *mvs = nullptr;
            if (volume->volume_idx() < 0) {
				auto it = std::lower_bound(aux_volume_state.begin(), aux_volume_state.end(), key, model_volume_state_lower);
                if (it != aux_volume_state.end() && it->geometry_id == key.geometry_id)
                    mvs = &(*it);
            } else {
				auto it = std::lower_bound(model_volume_state.begin(), model_volume_state.end(), key, model_volume_state_lower);
                if (it != model_volume_state.end() && it->geometry_id == key.geometry_id)
					mvs = &(*it);
            }
            // Emplace instance ID of the volume. Both the aux volumes and model volumes share the same instance ID.
            // The wipe tower has its own wipe_tower_instance_id().
            if (m_selection.contains_volume(volume_id))
                instance_ids_selected.emplace_back(volume->geometry_id.second);
            if (mvs == nullptr || force_full_scene_refresh) {
                // This GLVolume will be released.
                if (volume->is_wipe_tower) {
                    // There is only one wipe tower.
                    assert(volume_idx_wipe_tower_old == -1);
                    volume_idx_wipe_tower_old = (int)volume_id;
                }
                volume->release_geometry();
                if (! m_reload_delayed)
                    delete volume;
            } else {
                // This GLVolume will be reused.
                volume->set_sla_shift_z(0.0);
                map_glvolume_old_to_new[volume_id] = glvolumes_new.size();
                mvs->volume_idx = glvolumes_new.size();
                glvolumes_new.emplace_back(volume);
                // Update color of the volume based on the current extruder.
				if (mvs->model_volume != nullptr) {
					int extruder_id = mvs->model_volume->extruder_id();
					if (extruder_id != -1)
						volume->extruder_id = extruder_id;

                    volume->is_modifier = !mvs->model_volume->is_model_part();
                    volume->set_color_from_model_volume(mvs->model_volume);

                    // updates volumes transformations
                    volume->set_instance_transformation(mvs->model_volume->get_object()->instances[mvs->composite_id.instance_id]->get_transformation());
                    volume->set_volume_transformation(mvs->model_volume->get_transformation());
                }
            }
        }
        sort_remove_duplicates(instance_ids_selected);
    }

    if (m_reload_delayed)
        return;

	bool update_object_list = false;

    if (m_regenerate_volumes)
    {
		if (m_volumes.volumes != glvolumes_new)
			update_object_list = true;
        m_volumes.volumes = std::move(glvolumes_new);
        for (unsigned int obj_idx = 0; obj_idx < (unsigned int)m_model->objects.size(); ++ obj_idx) {
            const ModelObject &model_object = *m_model->objects[obj_idx];
            for (int volume_idx = 0; volume_idx < (int)model_object.volumes.size(); ++ volume_idx) {
				const ModelVolume &model_volume = *model_object.volumes[volume_idx];
                for (int instance_idx = 0; instance_idx < (int)model_object.instances.size(); ++ instance_idx) {
					const ModelInstance &model_instance = *model_object.instances[instance_idx];
					ModelVolumeState key(model_volume.id(), model_instance.id());
					auto it = std::lower_bound(model_volume_state.begin(), model_volume_state.end(), key, model_volume_state_lower);
					assert(it != model_volume_state.end() && it->geometry_id == key.geometry_id);
                    if (it->new_geometry()) {
                        // New volume.
                        m_volumes.load_object_volume(&model_object, obj_idx, volume_idx, instance_idx, m_color_by, m_use_VBOs && m_initialized);
						m_volumes.volumes.back()->geometry_id = key.geometry_id;
						update_object_list = true;
                    } else {
						// Recycling an old GLVolume.
						GLVolume &existing_volume = *m_volumes.volumes[it->volume_idx];
                        assert(existing_volume.geometry_id == key.geometry_id);
						// Update the Object/Volume/Instance indices into the current Model.
						if (existing_volume.composite_id != it->composite_id) {
							existing_volume.composite_id = it->composite_id;
							update_object_list = true;
						}
                    }
                }
            }
        }
        if (printer_technology == ptSLA) {
            size_t idx = 0;
            const SLAPrint *sla_print = this->sla_print();
			std::vector<double> shift_zs(m_model->objects.size(), 0);
            double relative_correction_z = sla_print->relative_correction().z();
            if (relative_correction_z <= EPSILON)
                relative_correction_z = 1.;
			for (const SLAPrintObject *print_object : sla_print->objects()) {
                SLASupportState   &state        = sla_support_state[idx ++];
                const ModelObject *model_object = print_object->model_object();
                // Find an index of the ModelObject
                int object_idx;
				if (std::all_of(state.step.begin(), state.step.end(), [](const PrintStateBase::StateWithTimeStamp &state){ return state.state != PrintStateBase::DONE; }))
					continue;
                // There may be new SLA volumes added to the scene for this print_object.
                // Find the object index of this print_object in the Model::objects list.
                auto it = std::find(sla_print->model().objects.begin(), sla_print->model().objects.end(), model_object);
                assert(it != sla_print->model().objects.end());
				object_idx = it - sla_print->model().objects.begin();
				// Cache the Z offset to be applied to all volumes with this object_idx.
				shift_zs[object_idx] = print_object->get_current_elevation() / relative_correction_z;
                // Collect indices of this print_object's instances, for which the SLA support meshes are to be added to the scene.
                // pairs of <instance_idx, print_instance_idx>
				std::vector<std::pair<size_t, size_t>> instances[std::tuple_size<SLASteps>::value];
                for (size_t print_instance_idx = 0; print_instance_idx < print_object->instances().size(); ++ print_instance_idx) {
                    const SLAPrintObject::Instance &instance = print_object->instances()[print_instance_idx];
                    // Find index of ModelInstance corresponding to this SLAPrintObject::Instance.
					auto it = std::find_if(model_object->instances.begin(), model_object->instances.end(), 
                        [&instance](const ModelInstance *mi) { return mi->id() == instance.instance_id; });
                    assert(it != model_object->instances.end());
                    int instance_idx = it - model_object->instances.begin();
                    for (size_t istep = 0; istep < sla_steps.size(); ++ istep)
                        if (state.step[istep].state == PrintStateBase::DONE) {
                            ModelVolumeState key(state.step[istep].timestamp, instance.instance_id.id);
                            auto it = std::lower_bound(aux_volume_state.begin(), aux_volume_state.end(), key, model_volume_state_lower);
                            assert(it != aux_volume_state.end() && it->geometry_id == key.geometry_id);
                            if (it->new_geometry())
                                instances[istep].emplace_back(std::pair<size_t, size_t>(instance_idx, print_instance_idx));
                            else
                                // Recycling an old GLVolume. Update the Object/Instance indices into the current Model.
                                m_volumes.volumes[it->volume_idx]->composite_id = GLVolume::CompositeID(object_idx, m_volumes.volumes[it->volume_idx]->volume_idx(), instance_idx);
                        }
                }

                // stores the current volumes count
                size_t volumes_count = m_volumes.volumes.size();

                for (size_t istep = 0; istep < sla_steps.size(); ++istep)
                    if (!instances[istep].empty())
                        m_volumes.load_object_auxiliary(print_object, object_idx, instances[istep], sla_steps[istep], state.step[istep].timestamp, m_use_VBOs && m_initialized);
            }

			// Shift-up all volumes of the object so that it has the right elevation with respect to the print bed
			for (GLVolume* volume : m_volumes.volumes)
				volume->set_sla_shift_z(shift_zs[volume->object_idx()]);
        }

        if (printer_technology == ptFFF && m_config->has("nozzle_diameter"))
        {
            // Should the wipe tower be visualized ?
            unsigned int extruders_count = (unsigned int)dynamic_cast<const ConfigOptionFloats*>(m_config->option("nozzle_diameter"))->values.size();

            bool semm = dynamic_cast<const ConfigOptionBool*>(m_config->option("single_extruder_multi_material"))->value;
            bool wt = dynamic_cast<const ConfigOptionBool*>(m_config->option("wipe_tower"))->value;
            bool co = dynamic_cast<const ConfigOptionBool*>(m_config->option("complete_objects"))->value;

            if ((extruders_count > 1) && semm && wt && !co)
            {
                // Height of a print (Show at least a slab)
                double height = std::max(m_model->bounding_box().max(2), 10.0);

                float x = dynamic_cast<const ConfigOptionFloat*>(m_config->option("wipe_tower_x"))->value;
                float y = dynamic_cast<const ConfigOptionFloat*>(m_config->option("wipe_tower_y"))->value;
                float w = dynamic_cast<const ConfigOptionFloat*>(m_config->option("wipe_tower_width"))->value;
                float a = dynamic_cast<const ConfigOptionFloat*>(m_config->option("wipe_tower_rotation_angle"))->value;

                const Print *print = m_process->fff_print();
                float depth = print->get_wipe_tower_depth();

                // Calculate wipe tower brim spacing.
                const DynamicPrintConfig &print_config  = wxGetApp().preset_bundle->prints.get_edited_preset().config;
                double layer_height                     = print_config.opt_float("layer_height");
                double first_layer_height               = print_config.get_abs_value("first_layer_height", layer_height);
                float brim_spacing = print->config().nozzle_diameter.values[0] * 1.25f - first_layer_height * (1. - M_PI_4);

                if (!print->is_step_done(psWipeTower))
                    depth = (900.f/w) * (float)(extruders_count - 1) ;
                int volume_idx_wipe_tower_new = m_volumes.load_wipe_tower_preview(
                    1000, x, y, w, depth, (float)height, a, m_use_VBOs && m_initialized, !print->is_step_done(psWipeTower),
                    brim_spacing * 4.5f);
                if (volume_idx_wipe_tower_old != -1)
                    map_glvolume_old_to_new[volume_idx_wipe_tower_old] = volume_idx_wipe_tower_new;
            }
        }

        update_volumes_colors_by_extruder();
		// Update selection indices based on the old/new GLVolumeCollection.
        if (m_selection.get_mode() == Selection::Instance)
            m_selection.instances_changed(instance_ids_selected);
        else
            m_selection.volumes_changed(map_glvolume_old_to_new);
	}

    m_gizmos.update_data(*this);
    m_gizmos.refresh_on_off_state(m_selection);

    // Update the toolbar
	if (update_object_list)
		post_event(SimpleEvent(EVT_GLCANVAS_OBJECT_SELECT));

    // checks for geometry outside the print volume to render it accordingly
    if (!m_volumes.empty())
    {
        ModelInstance::EPrintVolumeState state;

        const bool contained_min_one = m_volumes.check_outside_state(m_config, &state);

        _set_warning_texture(WarningTexture::ObjectClashed, state == ModelInstance::PVS_Partly_Outside);
        _set_warning_texture(WarningTexture::ObjectOutside, state == ModelInstance::PVS_Fully_Outside);

        post_event(Event<bool>(EVT_GLCANVAS_ENABLE_ACTION_BUTTONS, 
                               contained_min_one && !m_model->objects.empty() && state != ModelInstance::PVS_Partly_Outside));

// #ys_FIXME_delete_after_testing
//         bool contained = m_volumes.check_outside_state(m_config, &state);
//         if (!contained)
//         {
//             _set_warning_texture(WarningTexture::ObjectOutside, true);
//             post_event(Event<bool>(EVT_GLCANVAS_ENABLE_ACTION_BUTTONS, state == ModelInstance::PVS_Fully_Outside));
//         }
//         else
//         {
//             m_volumes.reset_outside_state();
//             _set_warning_texture(WarningTexture::ObjectOutside, false);
//             post_event(Event<bool>(EVT_GLCANVAS_ENABLE_ACTION_BUTTONS, !m_model->objects.empty()));
//         }
    }
    else
    {
        _set_warning_texture(WarningTexture::ObjectOutside, false);
        _set_warning_texture(WarningTexture::ObjectClashed, false);
        post_event(Event<bool>(EVT_GLCANVAS_ENABLE_ACTION_BUTTONS, false));
    }

    // restore to default value
    m_regenerate_volumes = true;

    m_camera.set_scene_box(scene_bounding_box());

    if (m_selection.is_empty())
    {
        // If no object is selected, deactivate the active gizmo, if any
        // Otherwise it may be shown after cleaning the scene (if it was active while the objects were deleted)
        m_gizmos.reset_all_states();

        // If no object is selected, reset the objects manipulator on the sidebar
        // to force a reset of its cache
        auto manip = wxGetApp().obj_manipul();
        if (manip != nullptr)
            manip->set_dirty();
    }

    // and force this canvas to be redrawn.
    m_dirty = true;
}

void GLCanvas3D::load_gcode_preview(const GCodePreviewData& preview_data, const std::vector<std::string>& str_tool_colors)
{
    const Print *print = this->fff_print();
    if ((m_canvas != nullptr) && (print != nullptr))
    {
        _set_current();

        std::vector<float> tool_colors = _parse_colors(str_tool_colors);

        if (m_volumes.empty())
        {
            m_gcode_preview_volume_index.reset();
            
            _load_gcode_extrusion_paths(preview_data, tool_colors);
            _load_gcode_travel_paths(preview_data, tool_colors);
            _load_gcode_retractions(preview_data);
            _load_gcode_unretractions(preview_data);
            
            if (!m_volumes.empty())
            {
                // removes empty volumes
                m_volumes.volumes.erase(std::remove_if(m_volumes.volumes.begin(), m_volumes.volumes.end(),
                    [](const GLVolume* volume) { return volume->print_zs.empty(); }), m_volumes.volumes.end());

                _load_fff_shells();
            }
            _update_toolpath_volumes_outside_state();
        }
        
        _update_gcode_volumes_visibility(preview_data);
        _show_warning_texture_if_needed(WarningTexture::ToolpathOutside);

        if (m_volumes.empty())
            reset_legend_texture();
        else
            _generate_legend_texture(preview_data, tool_colors);
    }
}

void GLCanvas3D::load_sla_preview()
{
    const SLAPrint* print = this->sla_print();
    if ((m_canvas != nullptr) && (print != nullptr))
    {
        _set_current();
        _load_sla_shells();
        _update_sla_shells_outside_state();
        _show_warning_texture_if_needed(WarningTexture::SlaSupportsOutside);
    }
}

void GLCanvas3D::load_preview(const std::vector<std::string>& str_tool_colors, const std::vector<double>& color_print_values)
{
    const Print *print = this->fff_print();
    if (print == nullptr)
        return;

    _set_current();

    _load_print_toolpaths();
    _load_wipe_tower_toolpaths(str_tool_colors);
    for (const PrintObject* object : print->objects())
    {
        if (object != nullptr)
            _load_print_object_toolpaths(*object, str_tool_colors, color_print_values);
    }

    for (GLVolume* volume : m_volumes.volumes)
    {
        volume->is_extrusion_path = true;
    }

    _update_toolpath_volumes_outside_state();
    _show_warning_texture_if_needed(WarningTexture::ToolpathOutside);
    if (color_print_values.empty())
        reset_legend_texture();
    else {
        auto preview_data = GCodePreviewData();
        preview_data.extrusion.view_type = GCodePreviewData::Extrusion::ColorPrint;
        const std::vector<float> tool_colors = _parse_colors(str_tool_colors);
        _generate_legend_texture(preview_data, tool_colors);
    }
}

void GLCanvas3D::bind_event_handlers()
{
    if (m_canvas != nullptr)
    {
        m_canvas->Bind(wxEVT_SIZE, &GLCanvas3D::on_size, this);
        m_canvas->Bind(wxEVT_IDLE, &GLCanvas3D::on_idle, this);
        m_canvas->Bind(wxEVT_CHAR, &GLCanvas3D::on_char, this);
        m_canvas->Bind(wxEVT_KEY_DOWN, &GLCanvas3D::on_key, this);
        m_canvas->Bind(wxEVT_KEY_UP, &GLCanvas3D::on_key, this);
        m_canvas->Bind(wxEVT_MOUSEWHEEL, &GLCanvas3D::on_mouse_wheel, this);
        m_canvas->Bind(wxEVT_TIMER, &GLCanvas3D::on_timer, this);
        m_canvas->Bind(wxEVT_LEFT_DOWN, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_LEFT_UP, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_MIDDLE_DOWN, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_MIDDLE_UP, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_RIGHT_DOWN, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_RIGHT_UP, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_MOTION, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_ENTER_WINDOW, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_LEAVE_WINDOW, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_LEFT_DCLICK, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_MIDDLE_DCLICK, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_RIGHT_DCLICK, &GLCanvas3D::on_mouse, this);
        m_canvas->Bind(wxEVT_PAINT, &GLCanvas3D::on_paint, this);
    }
}

void GLCanvas3D::unbind_event_handlers()
{
    if (m_canvas != nullptr)
    {
        m_canvas->Unbind(wxEVT_SIZE, &GLCanvas3D::on_size, this);
        m_canvas->Unbind(wxEVT_IDLE, &GLCanvas3D::on_idle, this);
        m_canvas->Unbind(wxEVT_CHAR, &GLCanvas3D::on_char, this);
        m_canvas->Unbind(wxEVT_KEY_DOWN, &GLCanvas3D::on_key, this);
        m_canvas->Unbind(wxEVT_KEY_UP, &GLCanvas3D::on_key, this);
        m_canvas->Unbind(wxEVT_MOUSEWHEEL, &GLCanvas3D::on_mouse_wheel, this);
        m_canvas->Unbind(wxEVT_TIMER, &GLCanvas3D::on_timer, this);
        m_canvas->Unbind(wxEVT_LEFT_DOWN, &GLCanvas3D::on_mouse, this);
		m_canvas->Unbind(wxEVT_LEFT_UP, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_MIDDLE_DOWN, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_MIDDLE_UP, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_RIGHT_DOWN, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_RIGHT_UP, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_MOTION, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_ENTER_WINDOW, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_LEAVE_WINDOW, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_LEFT_DCLICK, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_MIDDLE_DCLICK, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_RIGHT_DCLICK, &GLCanvas3D::on_mouse, this);
        m_canvas->Unbind(wxEVT_PAINT, &GLCanvas3D::on_paint, this);
    }
}

void GLCanvas3D::on_size(wxSizeEvent& evt)
{
    m_dirty = true;
}

void GLCanvas3D::on_idle(wxIdleEvent& evt)
{
    if (!m_initialized)
        return;

    m_dirty |= m_toolbar.update_items_state();
    m_dirty |= m_view_toolbar.update_items_state();

    if (!m_dirty)
        return;

    _refresh_if_shown_on_screen();

    if (m_keep_dirty)
        m_dirty = true;
}

void GLCanvas3D::on_char(wxKeyEvent& evt)
{
    if (!m_initialized)
        return;

    // see include/wx/defs.h enum wxKeyCode
    int keyCode = evt.GetKeyCode();
    int ctrlMask = wxMOD_CONTROL;

    auto imgui = wxGetApp().imgui();
    if (imgui->update_key_data(evt)) {
        render();
        return;
    }

    if ((keyCode == WXK_ESCAPE) && _deactivate_undo_redo_toolbar_items())
        return;

    if (m_gizmos.on_char(evt, *this))
        return;

//#ifdef __APPLE__
//    ctrlMask |= wxMOD_RAW_CONTROL;
//#endif /* __APPLE__ */
    if ((evt.GetModifiers() & ctrlMask) != 0) {
        switch (keyCode) {
#ifdef __APPLE__
        case 'a':
        case 'A':
#else /* __APPLE__ */
        case WXK_CONTROL_A:
#endif /* __APPLE__ */
                post_event(SimpleEvent(EVT_GLCANVAS_SELECT_ALL));
        break;
#ifdef __APPLE__
        case 'c':
        case 'C':
#else /* __APPLE__ */
        case WXK_CONTROL_C:
#endif /* __APPLE__ */
            post_event(SimpleEvent(EVT_GLTOOLBAR_COPY));
        break;
#ifdef __APPLE__
        case 'v':
        case 'V':
#else /* __APPLE__ */
        case WXK_CONTROL_V:
#endif /* __APPLE__ */
            post_event(SimpleEvent(EVT_GLTOOLBAR_PASTE));
        break;


#ifdef __APPLE__
        case 'y':
        case 'Y':
#else /* __APPLE__ */
        case WXK_CONTROL_Y:
#endif /* __APPLE__ */
            post_event(SimpleEvent(EVT_GLCANVAS_REDO));
        break;
#ifdef __APPLE__
        case 'z':
        case 'Z':
#else /* __APPLE__ */
        case WXK_CONTROL_Z:
#endif /* __APPLE__ */
            post_event(SimpleEvent(EVT_GLCANVAS_UNDO));
        break;

#ifdef __APPLE__
        case WXK_BACK: // the low cost Apple solutions are not equipped with a Delete key, use Backspace instead.
#else /* __APPLE__ */
        case WXK_DELETE:
#endif /* __APPLE__ */
                            post_event(SimpleEvent(EVT_GLTOOLBAR_DELETE_ALL)); break;
		default:            evt.Skip();
        }
    } else if (evt.HasModifiers()) {
        evt.Skip();
    } else {
        switch (keyCode)
        {
#ifdef __APPLE__
        case WXK_BACK: // the low cost Apple solutions are not equipped with a Delete key, use Backspace instead.
#else /* __APPLE__ */
		case WXK_DELETE:
#endif /* __APPLE__ */
                  post_event(SimpleEvent(EVT_GLTOOLBAR_DELETE));
                  break;
        case WXK_ESCAPE: { deselect_all(); break; }
        case '0': { select_view("iso"); break; }
        case '1': { select_view("top"); break; }
        case '2': { select_view("bottom"); break; }
        case '3': { select_view("front"); break; }
        case '4': { select_view("rear"); break; }
        case '5': { select_view("left"); break; }
        case '6': { select_view("right"); break; }
        case '+': { 
                    if (dynamic_cast<Preview*>(m_canvas->GetParent()) != nullptr)
                        post_event(wxKeyEvent(EVT_GLCANVAS_EDIT_COLOR_CHANGE, evt)); 
                    else
                        post_event(Event<int>(EVT_GLCANVAS_INCREASE_INSTANCES, +1)); 
                    break; }
        case '-': {  
                    if (dynamic_cast<Preview*>(m_canvas->GetParent()) != nullptr)
                        post_event(wxKeyEvent(EVT_GLCANVAS_EDIT_COLOR_CHANGE, evt)); 
                    else
                        post_event(Event<int>(EVT_GLCANVAS_INCREASE_INSTANCES, -1)); 
                    break; }
        case '?': { post_event(SimpleEvent(EVT_GLCANVAS_QUESTION_MARK)); break; }
        case 'A':
        case 'a': { post_event(SimpleEvent(EVT_GLCANVAS_ARRANGE)); break; }
        case 'B':
        case 'b': { zoom_to_bed(); break; }
        case 'I':
        case 'i': { set_camera_zoom(1.0); break; }
        case 'K':
        case 'k': { m_camera.select_next_type(); m_dirty = true; break; }
        case 'O':
        case 'o': { set_camera_zoom(-1.0); break; }
#if ENABLE_RENDER_PICKING_PASS
        case 'T':
        case 't': {
            m_show_picking_texture = !m_show_picking_texture;
            m_dirty = true; 
            break;
        }
#endif // ENABLE_RENDER_PICKING_PASS
        case 'Z':
        case 'z': { m_selection.is_empty() ? zoom_to_volumes() : zoom_to_selection(); break; }
        default:  { evt.Skip(); break; }
        }
    }
}

void GLCanvas3D::on_key(wxKeyEvent& evt)
{
    const int keyCode = evt.GetKeyCode();

    auto imgui = wxGetApp().imgui();
    if (imgui->update_key_data(evt)) {
        render();
    }
    else
    {
        if (!m_gizmos.on_key(evt, *this))
        {
            if (evt.GetEventType() == wxEVT_KEY_UP) {
                if (m_tab_down && keyCode == WXK_TAB && !evt.HasAnyModifiers()) {
                    // Enable switching between 3D and Preview with Tab
                    // m_canvas->HandleAsNavigationKey(evt);   // XXX: Doesn't work in some cases / on Linux
                    post_event(SimpleEvent(EVT_GLCANVAS_TAB));
                }
                else if (keyCode == WXK_SHIFT)
                {
                    if (m_picking_enabled && m_rectangle_selection.is_dragging())
                    {
                        _update_selection_from_hover();
                        m_rectangle_selection.stop_dragging();
                        m_mouse.ignore_left_up = true;
                        m_dirty = true;
                    }
//                    set_cursor(Standard);
                }
                else if (keyCode == WXK_ALT)
                {
                    if (m_picking_enabled && m_rectangle_selection.is_dragging())
                    {
                        _update_selection_from_hover();
                        m_rectangle_selection.stop_dragging();
                        m_mouse.ignore_left_up = true;
                        m_dirty = true;
                    }
//                    set_cursor(Standard);
                }
                else if (keyCode == WXK_CONTROL)
                    m_dirty = true;
            }
            else if (evt.GetEventType() == wxEVT_KEY_DOWN) {
                m_tab_down = keyCode == WXK_TAB && !evt.HasAnyModifiers();
                if (keyCode == WXK_SHIFT)
                {
                    if (m_picking_enabled && (m_gizmos.get_current_type() != GLGizmosManager::SlaSupports))
                    {
                        m_mouse.ignore_left_up = false;
//                        set_cursor(Cross);
                    }
                }
                else if (keyCode == WXK_ALT)
                {
                    if (m_picking_enabled && (m_gizmos.get_current_type() != GLGizmosManager::SlaSupports))
                    {
                        m_mouse.ignore_left_up = false;
//                        set_cursor(Cross);
                    }
                }
                else if (keyCode == WXK_CONTROL)
                    m_dirty = true;
                // DoubleSlider navigation in Preview
                else if (keyCode == WXK_LEFT    || 
                         keyCode == WXK_RIGHT   ||
                         keyCode == WXK_UP      || 
                         keyCode == WXK_DOWN    )
                {
                    if (dynamic_cast<Preview*>(m_canvas->GetParent()) != nullptr)
                        post_event(wxKeyEvent(EVT_GLCANVAS_MOVE_DOUBLE_SLIDER, evt));
                }
            }
        }
    }

    if (keyCode != WXK_TAB
        && keyCode != WXK_LEFT
        && keyCode != WXK_UP
        && keyCode != WXK_RIGHT
        && keyCode != WXK_DOWN) {
        evt.Skip();   // Needed to have EVT_CHAR generated as well
    }
}

void GLCanvas3D::on_mouse_wheel(wxMouseEvent& evt)
{
    if (!m_initialized)
        return;

    // Ignore the wheel events if the middle button is pressed.
    if (evt.MiddleIsDown())
        return;

#if ENABLE_RETINA_GL
    const float scale = m_retina_helper->get_scale_factor();
    evt.SetX(evt.GetX() * scale);
    evt.SetY(evt.GetY() * scale);
#endif

    // Performs layers editing updates, if enabled
    if (is_layers_editing_enabled())
    {
        int object_idx_selected = m_selection.get_object_idx();
        if (object_idx_selected != -1)
        {
            // A volume is selected. Test, whether hovering over a layer thickness bar.
            if (m_layers_editing.bar_rect_contains(*this, (float)evt.GetX(), (float)evt.GetY()))
            {
                // Adjust the width of the selection.
                m_layers_editing.band_width = std::max(std::min(m_layers_editing.band_width * (1.0f + 0.1f * (float)evt.GetWheelRotation() / (float)evt.GetWheelDelta()), 10.0f), 1.5f);
                if (m_canvas != nullptr)
                    m_canvas->Refresh();

                return;
            }
        }
    }

    // Inform gizmos about the event so they have the opportunity to react.
    if (m_gizmos.on_mouse_wheel(evt, *this))
        return;

    // Calculate the zoom delta and apply it to the current zoom factor
    set_camera_zoom((double)evt.GetWheelRotation() / (double)evt.GetWheelDelta());
}

void GLCanvas3D::on_timer(wxTimerEvent& evt)
{
    if (m_layers_editing.state == LayersEditing::Editing)
        _perform_layer_editing_action();
}

#ifndef NDEBUG
// #define SLIC3R_DEBUG_MOUSE_EVENTS
#endif

#ifdef SLIC3R_DEBUG_MOUSE_EVENTS
std::string format_mouse_event_debug_message(const wxMouseEvent &evt)
{
	static int idx = 0;
	char buf[2048];
	std::string out;
	sprintf(buf, "Mouse Event %d - ", idx ++);
	out = buf;

	if (evt.Entering())
		out += "Entering ";
	if (evt.Leaving())
		out += "Leaving ";
	if (evt.Dragging())
		out += "Dragging ";
	if (evt.Moving())
		out += "Moving ";
	if (evt.Magnify())
		out += "Magnify ";
	if (evt.LeftDown())
		out += "LeftDown ";
	if (evt.LeftUp())
		out += "LeftUp ";
	if (evt.LeftDClick())
		out += "LeftDClick ";
	if (evt.MiddleDown())
		out += "MiddleDown ";
	if (evt.MiddleUp())
		out += "MiddleUp ";
	if (evt.MiddleDClick())
		out += "MiddleDClick ";
	if (evt.RightDown())
		out += "RightDown ";
	if (evt.RightUp())
		out += "RightUp ";
	if (evt.RightDClick())
		out += "RightDClick ";

	sprintf(buf, "(%d, %d)", evt.GetX(), evt.GetY());
	out += buf;
	return out;
}
#endif /* SLIC3R_DEBUG_MOUSE_EVENTS */

void GLCanvas3D::on_mouse(wxMouseEvent& evt)
{
    auto mouse_up_cleanup = [this](){
        m_moving = false;
        m_mouse.drag.move_volume_idx = -1;
        m_mouse.set_start_position_3D_as_invalid();
        m_mouse.set_start_position_2D_as_invalid();
        m_mouse.dragging = false;
        m_mouse.ignore_left_up = false;
        m_dirty = true;

        if (m_canvas->HasCapture())
            m_canvas->ReleaseMouse();
    };

#if ENABLE_RETINA_GL
    const float scale = m_retina_helper->get_scale_factor();
    evt.SetX(evt.GetX() * scale);
    evt.SetY(evt.GetY() * scale);
#endif

	Point pos(evt.GetX(), evt.GetY());

    ImGuiWrapper *imgui = wxGetApp().imgui();
    if (imgui->update_mouse_data(evt)) {
        m_mouse.position = evt.Leaving() ? Vec2d(-1.0, -1.0) : pos.cast<double>();
        render();
#ifdef SLIC3R_DEBUG_MOUSE_EVENTS
		printf((format_mouse_event_debug_message(evt) + " - Consumed by ImGUI\n").c_str());
#endif /* SLIC3R_DEBUG_MOUSE_EVENTS */
		return;
    }

#ifdef __WXMSW__
	bool on_enter_workaround = false;
    if (! evt.Entering() && ! evt.Leaving() && m_mouse.position.x() == -1.0) {
        // Workaround for SPE-832: There seems to be a mouse event sent to the window before evt.Entering()
        m_mouse.position = pos.cast<double>();
        render();
#ifdef SLIC3R_DEBUG_MOUSE_EVENTS
		printf((format_mouse_event_debug_message(evt) + " - OnEnter workaround\n").c_str());
#endif /* SLIC3R_DEBUG_MOUSE_EVENTS */
		on_enter_workaround = true;
    } else 
#endif /* __WXMSW__ */
    {
#ifdef SLIC3R_DEBUG_MOUSE_EVENTS
		printf((format_mouse_event_debug_message(evt) + " - other\n").c_str());
#endif /* SLIC3R_DEBUG_MOUSE_EVENTS */
	}

    if (m_toolbar.on_mouse(evt, *this))
    {
        if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
            mouse_up_cleanup();
        m_mouse.set_start_position_3D_as_invalid();
        return;
    }

    if (m_view_toolbar.on_mouse(evt, *this))
    {
        if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
            mouse_up_cleanup();
        m_mouse.set_start_position_3D_as_invalid();
        return;
    }

    if (m_gizmos.on_mouse(evt, *this))
    {
        if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
            mouse_up_cleanup();

        m_mouse.set_start_position_3D_as_invalid();
        return;
    }

    if (m_picking_enabled)
        _set_current();

    int selected_object_idx = m_selection.get_object_idx();
    int layer_editing_object_idx = is_layers_editing_enabled() ? selected_object_idx : -1;
    m_layers_editing.select_object(*m_model, layer_editing_object_idx);

    if (m_mouse.drag.move_requires_threshold && m_mouse.is_move_start_threshold_position_2D_defined() && m_mouse.is_move_threshold_met(pos))
    {
        m_mouse.drag.move_requires_threshold = false;
        m_mouse.set_move_start_threshold_position_2D_as_invalid();
    }

    if (evt.ButtonDown() && wxWindow::FindFocus() != this->m_canvas)
        // Grab keyboard focus on any mouse click event.
        m_canvas->SetFocus();

    if (evt.Entering())
    {
//#if defined(__WXMSW__) || defined(__linux__)
//        // On Windows and Linux needs focus in order to catch key events
        // Set focus in order to remove it from sidebar fields
        if (m_canvas != nullptr) {
            // Only set focus, if the top level window of this canvas is active.
            auto p = dynamic_cast<wxWindow*>(evt.GetEventObject());
            while (p->GetParent())
                p = p->GetParent();
            auto *top_level_wnd = dynamic_cast<wxTopLevelWindow*>(p);
            if (top_level_wnd && top_level_wnd->IsActive())
                m_canvas->SetFocus();
            m_mouse.position = pos.cast<double>();
            // 1) forces a frame render to ensure that m_hover_volume_idxs is updated even when the user right clicks while
            // the context menu is shown, ensuring it to disappear if the mouse is outside any volume and to
            // change the volume hover state if any is under the mouse 
            // 2) when switching between 3d view and preview the size of the canvas changes if the side panels are visible,
            // so forces a resize to avoid multiple renders with different sizes (seen as flickering)
            _refresh_if_shown_on_screen();
        }
        m_mouse.set_start_position_2D_as_invalid();
//#endif
    }
    else if (evt.Leaving())
    {
        _deactivate_undo_redo_toolbar_items();

        // to remove hover on objects when the mouse goes out of this canvas
        m_mouse.position = Vec2d(-1.0, -1.0);
        m_dirty = true;
    }
    else if (evt.LeftDown() || evt.RightDown() || evt.MiddleDown())
    {
        if (_deactivate_undo_redo_toolbar_items())
            return;

        // If user pressed left or right button we first check whether this happened
        // on a volume or not.
        m_layers_editing.state = LayersEditing::Unknown;
        if ((layer_editing_object_idx != -1) && m_layers_editing.bar_rect_contains(*this, pos(0), pos(1)))
        {
            // A volume is selected and the mouse is inside the layer thickness bar.
            // Start editing the layer height.
            m_layers_editing.state = LayersEditing::Editing;
            _perform_layer_editing_action(&evt);
        }
        else if ((layer_editing_object_idx != -1) && m_layers_editing.reset_rect_contains(*this, pos(0), pos(1)))
        {
            if (evt.LeftDown())
            {
                // A volume is selected and the mouse is inside the reset button. Reset the ModelObject's layer height profile.
				m_layers_editing.reset_layer_height_profile(*this);
                // Index 2 means no editing, just wait for mouse up event.
                m_layers_editing.state = LayersEditing::Completed;

                m_dirty = true;
            }
        }
        else if (evt.LeftDown() && (evt.ShiftDown() || evt.AltDown()) && m_picking_enabled)
        {
            if (m_gizmos.get_current_type() != GLGizmosManager::SlaSupports)
            {
                m_rectangle_selection.start_dragging(m_mouse.position, evt.ShiftDown() ? GLSelectionRectangle::Select : GLSelectionRectangle::Deselect);
                m_dirty = true;
            }
        }
        else
        {
            // Select volume in this 3D canvas.
            // Don't deselect a volume if layer editing is enabled. We want the object to stay selected
            // during the scene manipulation.

            if (m_picking_enabled && (!m_hover_volume_idxs.empty() || !is_layers_editing_enabled()))
            {
                if (evt.LeftDown() && !m_hover_volume_idxs.empty())
                {
                    int volume_idx = get_first_hover_volume_idx();
                    bool already_selected = m_selection.contains_volume(volume_idx);
                    bool ctrl_down = evt.CmdDown();

                    Selection::IndicesList curr_idxs = m_selection.get_volume_idxs();

                    if (already_selected && ctrl_down)
                        m_selection.remove(volume_idx);
                    else
                    {
                        m_selection.add(volume_idx, !ctrl_down, true);
                        m_mouse.drag.move_requires_threshold = !already_selected;
                        if (already_selected)
                            m_mouse.set_move_start_threshold_position_2D_as_invalid();
                        else
                            m_mouse.drag.move_start_threshold_position_2D = pos;
                    }

                    // propagate event through callback
                    if (curr_idxs != m_selection.get_volume_idxs())
                    {
                        if (m_selection.is_empty())
                            m_gizmos.reset_all_states();
                        else
                            m_gizmos.refresh_on_off_state(m_selection);

                        m_gizmos.update_data(*this);
                        post_event(SimpleEvent(EVT_GLCANVAS_OBJECT_SELECT));
                        m_dirty = true;
                    }
                }
            }

            if (!m_hover_volume_idxs.empty())
            {
                if (evt.LeftDown() && m_moving_enabled && (m_mouse.drag.move_volume_idx == -1))
                {
                    // Only accept the initial position, if it is inside the volume bounding box.
                    int volume_idx = get_first_hover_volume_idx();
                    BoundingBoxf3 volume_bbox = m_volumes.volumes[volume_idx]->transformed_bounding_box();
                    volume_bbox.offset(1.0);
                    if (volume_bbox.contains(m_mouse.scene_position))
                    {
                        // The dragging operation is initiated.
                        m_mouse.drag.move_volume_idx = volume_idx;
                        m_selection.start_dragging();
                        m_mouse.drag.start_position_3D = m_mouse.scene_position;
                        m_moving = true;
                    }
                }
            }
        }
    }
    else if (evt.Dragging() && evt.LeftIsDown() && (m_layers_editing.state == LayersEditing::Unknown) && (m_mouse.drag.move_volume_idx != -1))
    {
        if (!m_mouse.drag.move_requires_threshold)
        {
            m_mouse.dragging = true;

            Vec3d cur_pos = m_mouse.drag.start_position_3D;
            // we do not want to translate objects if the user just clicked on an object while pressing shift to remove it from the selection and then drag
            if (m_selection.contains_volume(get_first_hover_volume_idx()))
            {
                if (m_camera.get_theta() == 90.0f)
                {
                    // side view -> move selected volumes orthogonally to camera view direction
                    Linef3 ray = mouse_ray(pos);
                    Vec3d dir = ray.unit_vector();
                    // finds the intersection of the mouse ray with the plane parallel to the camera viewport and passing throught the starting position
                    // use ray-plane intersection see i.e. https://en.wikipedia.org/wiki/Line%E2%80%93plane_intersection algebric form
                    // in our case plane normal and ray direction are the same (orthogonal view)
                    // when moving to perspective camera the negative z unit axis of the camera needs to be transformed in world space and used as plane normal
                    Vec3d inters = ray.a + (m_mouse.drag.start_position_3D - ray.a).dot(dir) / dir.squaredNorm() * dir;
                    // vector from the starting position to the found intersection
                    Vec3d inters_vec = inters - m_mouse.drag.start_position_3D;

                    Vec3d camera_right = m_camera.get_dir_right();
                    Vec3d camera_up = m_camera.get_dir_up();

                    // finds projection of the vector along the camera axes
                    double projection_x = inters_vec.dot(camera_right);
                    double projection_z = inters_vec.dot(camera_up);

                    // apply offset
                    cur_pos = m_mouse.drag.start_position_3D + projection_x * camera_right + projection_z * camera_up;
                }
                else
                {
                    // Generic view
                    // Get new position at the same Z of the initial click point.
                    float z0 = 0.0f;
                    float z1 = 1.0f;
                    cur_pos = Linef3(_mouse_to_3d(pos, &z0), _mouse_to_3d(pos, &z1)).intersect_plane(m_mouse.drag.start_position_3D(2));
                }
            }

            m_regenerate_volumes = false;
            m_selection.translate(cur_pos - m_mouse.drag.start_position_3D);
            wxGetApp().obj_manipul()->set_dirty();
            m_dirty = true;
        }
    }
    else if (evt.Dragging() && evt.LeftIsDown() && m_picking_enabled && m_rectangle_selection.is_dragging())
    {
        m_rectangle_selection.dragging(pos.cast<double>());
        m_dirty = true;
    }
    else if (evt.Dragging())
    {
        m_mouse.dragging = true;

        if ((m_layers_editing.state != LayersEditing::Unknown) && (layer_editing_object_idx != -1))
        {
            if (m_layers_editing.state == LayersEditing::Editing)
                _perform_layer_editing_action(&evt);
        }
        // do not process the dragging if the left mouse was set down in another canvas
        else if (evt.LeftIsDown())
        {
            // if dragging over blank area with left button, rotate
            if (m_hover_volume_idxs.empty() && m_mouse.is_start_position_3D_defined())
            {
                const Vec3d& orig = m_mouse.drag.start_position_3D;
                float sign = m_camera.inverted_phi ? -1.0f : 1.0f;
                m_camera.phi += sign * ((float)pos(0) - (float)orig(0)) * TRACKBALLSIZE;
                m_camera.set_theta(m_camera.get_theta() - ((float)pos(1) - (float)orig(1)) * TRACKBALLSIZE, wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA);
                m_dirty = true;
            }
            m_mouse.drag.start_position_3D = Vec3d((double)pos(0), (double)pos(1), 0.0);
        }
        else if (evt.MiddleIsDown() || evt.RightIsDown())
        {
            // If dragging over blank area with right button, pan.
            if (m_mouse.is_start_position_2D_defined())
            {
                // get point in model space at Z = 0
                float z = 0.0f;
                const Vec3d& cur_pos = _mouse_to_3d(pos, &z);
                Vec3d orig = _mouse_to_3d(m_mouse.drag.start_position_2D, &z);
                m_camera.set_target(m_camera.get_target() + orig - cur_pos);
                m_dirty = true;
            }
            
            m_mouse.drag.start_position_2D = pos;
        }
    }
    else if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
    {
        if (m_layers_editing.state != LayersEditing::Unknown)
        {
            m_layers_editing.state = LayersEditing::Unknown;
            _stop_timer();
            m_layers_editing.accept_changes(*this);
        }
        else if ((m_mouse.drag.move_volume_idx != -1) && m_mouse.dragging)
        {
            m_regenerate_volumes = false;
            do_move("Move Object");
            wxGetApp().obj_manipul()->set_dirty();
            // Let the plater know that the dragging finished, so a delayed refresh
            // of the scene with the background processing data should be performed.
            post_event(SimpleEvent(EVT_GLCANVAS_MOUSE_DRAGGING_FINISHED));
        }
        else if (evt.LeftUp() && m_picking_enabled && m_rectangle_selection.is_dragging())
        {
            if (evt.ShiftDown() || evt.AltDown())
                _update_selection_from_hover();

            m_rectangle_selection.stop_dragging();
        }
        else if (evt.LeftUp() && !m_mouse.ignore_left_up && !m_mouse.dragging && m_hover_volume_idxs.empty() && !is_layers_editing_enabled())
        {
            // deselect and propagate event through callback
            if (!evt.ShiftDown() && m_picking_enabled)
                deselect_all();
        }
        else if (evt.LeftUp() && m_mouse.dragging)
            // Flips X mouse deltas if bed is upside down
            m_camera.inverted_phi = (m_camera.get_dir_up()(2) < 0.0);
        else if (evt.RightUp())
        {
            m_mouse.position = pos.cast<double>();
            // forces a frame render to ensure that m_hover_volume_idxs is updated even when the user right clicks while
            // the context menu is already shown
            render();
            if (!m_hover_volume_idxs.empty())
            {
                // if right clicking on volume, propagate event through callback (shows context menu)
                int volume_idx = get_first_hover_volume_idx();
                if (!m_volumes.volumes[volume_idx]->is_wipe_tower // no context menu for the wipe tower
                    && m_gizmos.get_current_type() != GLGizmosManager::SlaSupports)  // disable context menu when the gizmo is open
                {
                    // forces the selection of the volume
                    m_selection.add(volume_idx);
                    m_gizmos.refresh_on_off_state(m_selection);
                    post_event(SimpleEvent(EVT_GLCANVAS_OBJECT_SELECT));
                    m_gizmos.update_data(*this);
                    wxGetApp().obj_manipul()->set_dirty();
                    // forces a frame render to update the view before the context menu is shown
                    render();

                    Vec2d logical_pos = pos.cast<double>();
#if ENABLE_RETINA_GL
                    const float factor = m_retina_helper->get_scale_factor();
                    logical_pos = logical_pos.cwiseQuotient(Vec2d(factor, factor));
#endif // ENABLE_RETINA_GL
                    post_event(Vec2dEvent(EVT_GLCANVAS_RIGHT_CLICK, logical_pos));
                }
            }
        }

        mouse_up_cleanup();
    }
    else if (evt.Moving())
    {
        m_mouse.position = pos.cast<double>();
        std::string tooltip = "";

        if (tooltip.empty())
            tooltip = m_gizmos.get_tooltip();

        if (tooltip.empty())
            tooltip = m_toolbar.get_tooltip();

        if (tooltip.empty())
            tooltip = m_view_toolbar.get_tooltip();

        set_tooltip(tooltip);

        // updates gizmos overlay
        if (m_selection.is_empty())
            m_gizmos.reset_all_states();

        // Only refresh if picking is enabled, in that case the objects may get highlighted if the mouse cursor hovers over.
        if (m_picking_enabled)
            m_dirty = true;
    }
    else
        evt.Skip();

#ifdef __WXMSW__
	if (on_enter_workaround)
		m_mouse.position = Vec2d(-1., -1.);
#endif /* __WXMSW__ */
}

void GLCanvas3D::on_paint(wxPaintEvent& evt)
{
    if (m_initialized)
        m_dirty = true;
    else
        // Call render directly, so it gets initialized immediately, not from On Idle handler.
        this->render();
}

Size GLCanvas3D::get_canvas_size() const
{
    int w = 0;
    int h = 0;

    if (m_canvas != nullptr)
        m_canvas->GetSize(&w, &h);

#if ENABLE_RETINA_GL
    const float factor = m_retina_helper->get_scale_factor();
    w *= factor;
    h *= factor;
#else
    const float factor = 1.0f;
#endif

    return Size(w, h, factor);
}

Vec2d GLCanvas3D::get_local_mouse_position() const
{
    if (m_canvas == nullptr)
		return Vec2d::Zero();

    wxPoint mouse_pos = m_canvas->ScreenToClient(wxGetMousePosition());
    const double factor = 
#if ENABLE_RETINA_GL
        m_retina_helper->get_scale_factor();
#else
        1.0;
#endif
    return Vec2d(factor * mouse_pos.x, factor * mouse_pos.y);
}

void GLCanvas3D::reset_legend_texture()
{
    if (m_legend_texture.get_id() != 0)
    {
        _set_current();
        m_legend_texture.reset();
    }
}

void GLCanvas3D::set_tooltip(const std::string& tooltip) const
{
    if (m_canvas != nullptr)
    {
        wxToolTip* t = m_canvas->GetToolTip();
        if (t != nullptr)
        {
            if (tooltip.empty())
                m_canvas->UnsetToolTip();
            else
                t->SetTip(wxString::FromUTF8(tooltip.data()));
        }
        else if (!tooltip.empty()) // Avoid "empty" tooltips => unset of the empty tooltip leads to application crash under OSX
            m_canvas->SetToolTip(wxString::FromUTF8(tooltip.data()));
    }
}


void GLCanvas3D::do_move(const std::string& snapshot_type)
{
    if (m_model == nullptr)
        return;

    if (!snapshot_type.empty())
        wxGetApp().plater()->take_snapshot(_(L(snapshot_type)));

    std::set<std::pair<int, int>> done;  // keeps track of modified instances
    bool object_moved = false;
    Vec3d wipe_tower_origin = Vec3d::Zero();

    Selection::EMode selection_mode = m_selection.get_mode();

    for (const GLVolume* v : m_volumes.volumes)
    {
        int object_idx = v->object_idx();
        int instance_idx = v->instance_idx();
        int volume_idx = v->volume_idx();

        std::pair<int, int> done_id(object_idx, instance_idx);

        if ((0 <= object_idx) && (object_idx < (int)m_model->objects.size()))
        {
            done.insert(done_id);

            // Move instances/volumes
            ModelObject* model_object = m_model->objects[object_idx];
            if (model_object != nullptr)
            {
                if (selection_mode == Selection::Instance)
                    model_object->instances[instance_idx]->set_offset(v->get_instance_offset());
                else if (selection_mode == Selection::Volume)
                    model_object->volumes[volume_idx]->set_offset(v->get_volume_offset());

                object_moved = true;
                model_object->invalidate_bounding_box();
            }
        }
        else if (object_idx == 1000)
            // Move a wipe tower proxy.
            wipe_tower_origin = v->get_volume_offset();
    }

    // Fixes sinking/flying instances
    for (const std::pair<int, int>& i : done)
    {
        ModelObject* m = m_model->objects[i.first];
        Vec3d shift(0.0, 0.0, -m->get_instance_min_z(i.second));
        m_selection.translate(i.first, i.second, shift);
        m->translate_instance(i.second, shift);
    }

    if (object_moved)
        post_event(SimpleEvent(EVT_GLCANVAS_INSTANCE_MOVED));

    if (wipe_tower_origin != Vec3d::Zero())
        post_event(Vec3dEvent(EVT_GLCANVAS_WIPETOWER_MOVED, std::move(wipe_tower_origin)));

    m_dirty = true;
}

void GLCanvas3D::do_rotate(const std::string& snapshot_type)
{
    if (m_model == nullptr)
        return;

    if (!snapshot_type.empty())
        wxGetApp().plater()->take_snapshot(_(L(snapshot_type)));

    std::set<std::pair<int, int>> done;  // keeps track of modified instances

    Selection::EMode selection_mode = m_selection.get_mode();

    for (const GLVolume* v : m_volumes.volumes)
    {
        int object_idx = v->object_idx();
        if (object_idx == 1000) { // the wipe tower
            Vec3d offset = v->get_volume_offset();
            post_event(Vec3dEvent(EVT_GLCANVAS_WIPETOWER_ROTATED, Vec3d(offset(0), offset(1), v->get_volume_rotation()(2))));
        }
        if ((object_idx < 0) || ((int)m_model->objects.size() <= object_idx))
            continue;

        int instance_idx = v->instance_idx();
        int volume_idx = v->volume_idx();

        done.insert(std::pair<int, int>(object_idx, instance_idx));

        // Rotate instances/volumes.
        ModelObject* model_object = m_model->objects[object_idx];
        if (model_object != nullptr)
        {
            if (selection_mode == Selection::Instance)
            {
                model_object->instances[instance_idx]->set_rotation(v->get_instance_rotation());
                model_object->instances[instance_idx]->set_offset(v->get_instance_offset());
            }
            else if (selection_mode == Selection::Volume)
            {
                model_object->volumes[volume_idx]->set_rotation(v->get_volume_rotation());
                model_object->volumes[volume_idx]->set_offset(v->get_volume_offset());
            }
            model_object->invalidate_bounding_box();
        }
    }

    // Fixes sinking/flying instances
    for (const std::pair<int, int>& i : done)
    {
        ModelObject* m = m_model->objects[i.first];
        Vec3d shift(0.0, 0.0, -m->get_instance_min_z(i.second));
        m_selection.translate(i.first, i.second, shift);
        m->translate_instance(i.second, shift);
    }

    if (!done.empty())
        post_event(SimpleEvent(EVT_GLCANVAS_INSTANCE_ROTATED));

    m_dirty = true;
}

void GLCanvas3D::do_scale(const std::string& snapshot_type)
{
    if (m_model == nullptr)
        return;

    if (!snapshot_type.empty())
        wxGetApp().plater()->take_snapshot(_(L(snapshot_type)));

    std::set<std::pair<int, int>> done;  // keeps track of modified instances

    Selection::EMode selection_mode = m_selection.get_mode();

    for (const GLVolume* v : m_volumes.volumes)
    {
        int object_idx = v->object_idx();
        if ((object_idx < 0) || ((int)m_model->objects.size() <= object_idx))
            continue;

        int instance_idx = v->instance_idx();
        int volume_idx = v->volume_idx();

        done.insert(std::pair<int, int>(object_idx, instance_idx));

        // Rotate instances/volumes
        ModelObject* model_object = m_model->objects[object_idx];
        if (model_object != nullptr)
        {
            if (selection_mode == Selection::Instance)
            {
                model_object->instances[instance_idx]->set_scaling_factor(v->get_instance_scaling_factor());
                model_object->instances[instance_idx]->set_offset(v->get_instance_offset());
            }
            else if (selection_mode == Selection::Volume)
            {
                model_object->instances[instance_idx]->set_offset(v->get_instance_offset());
                model_object->volumes[volume_idx]->set_scaling_factor(v->get_volume_scaling_factor());
                model_object->volumes[volume_idx]->set_offset(v->get_volume_offset());
            }
            model_object->invalidate_bounding_box();
        }
    }

    // Fixes sinking/flying instances
    for (const std::pair<int, int>& i : done)
    {
        ModelObject* m = m_model->objects[i.first];
        Vec3d shift(0.0, 0.0, -m->get_instance_min_z(i.second));
        m_selection.translate(i.first, i.second, shift);
        m->translate_instance(i.second, shift);
    }

    if (!done.empty())
        post_event(SimpleEvent(EVT_GLCANVAS_INSTANCE_ROTATED));

    m_dirty = true;
}

void GLCanvas3D::do_flatten(const Vec3d& normal, const std::string& snapshot_type)
{
    if (!snapshot_type.empty())
        wxGetApp().plater()->take_snapshot(_(L(snapshot_type)));

    m_selection.flattening_rotate(normal);
    do_rotate(""); // avoid taking another snapshot
}

void GLCanvas3D::do_mirror(const std::string& snapshot_type)
{
    if (m_model == nullptr)
        return;

    if (!snapshot_type.empty())
        wxGetApp().plater()->take_snapshot(_(L(snapshot_type)));

    std::set<std::pair<int, int>> done;  // keeps track of modified instances

    Selection::EMode selection_mode = m_selection.get_mode();

    for (const GLVolume* v : m_volumes.volumes)
    {
        int object_idx = v->object_idx();
        if ((object_idx < 0) || ((int)m_model->objects.size() <= object_idx))
            continue;

        int instance_idx = v->instance_idx();
        int volume_idx = v->volume_idx();

        done.insert(std::pair<int, int>(object_idx, instance_idx));

        // Mirror instances/volumes
        ModelObject* model_object = m_model->objects[object_idx];
        if (model_object != nullptr)
        {
            if (selection_mode == Selection::Instance)
                model_object->instances[instance_idx]->set_mirror(v->get_instance_mirror());
            else if (selection_mode == Selection::Volume)
                model_object->volumes[volume_idx]->set_mirror(v->get_volume_mirror());

            model_object->invalidate_bounding_box();
        }
    }

    // Fixes sinking/flying instances
    for (const std::pair<int, int>& i : done)
    {
        ModelObject* m = m_model->objects[i.first];
        Vec3d shift(0.0, 0.0, -m->get_instance_min_z(i.second));
        m_selection.translate(i.first, i.second, shift);
        m->translate_instance(i.second, shift);
    }

    post_event(SimpleEvent(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS));

    m_dirty = true;
}

void GLCanvas3D::set_camera_zoom(double zoom)
{
    const Size& cnv_size = get_canvas_size();
    m_camera.set_zoom(zoom, _max_bounding_box(false), cnv_size.get_width(), cnv_size.get_height());
    m_dirty = true;
}

void GLCanvas3D::update_gizmos_on_off_state()
{
    set_as_dirty();
    m_gizmos.update_data(*this);
    m_gizmos.refresh_on_off_state(get_selection());
}

void GLCanvas3D::handle_sidebar_focus_event(const std::string& opt_key, bool focus_on)
{
    m_sidebar_field = focus_on ? opt_key : "";

    if (!m_sidebar_field.empty())
    {
        m_gizmos.reset_all_states();
        m_dirty = true;
    }
}

void GLCanvas3D::handle_layers_data_focus_event(const t_layer_height_range range, const EditorType type)
{
    std::string field = "layer_" + std::to_string(type) + "_" + std::to_string(range.first) + "_" + std::to_string(range.second);
    handle_sidebar_focus_event(field, true);
}

void GLCanvas3D::update_ui_from_settings()
{
    m_camera.set_type(wxGetApp().app_config->get("use_perspective_camera"));
    m_dirty = true;

#if ENABLE_RETINA_GL
    const float orig_scaling = m_retina_helper->get_scale_factor();

    const bool use_retina = wxGetApp().app_config->get("use_retina_opengl") == "1";
    BOOST_LOG_TRIVIAL(debug) << "GLCanvas3D: Use Retina OpenGL: " << use_retina;
    m_retina_helper->set_use_retina(use_retina);
    const float new_scaling = m_retina_helper->get_scale_factor();

    if (new_scaling != orig_scaling) {
        BOOST_LOG_TRIVIAL(debug) << "GLCanvas3D: Scaling factor: " << new_scaling;

        m_camera.set_zoom(m_camera.get_zoom() * new_scaling / orig_scaling);
        _refresh_if_shown_on_screen();
    }
#endif
}



arr::WipeTowerInfo GLCanvas3D::get_wipe_tower_info() const
{
    arr::WipeTowerInfo wti;
    for (const GLVolume* vol : m_volumes.volumes) {
        if (vol->is_wipe_tower) {
            wti.is_wipe_tower = true;
            wti.pos = Vec2d(m_config->opt_float("wipe_tower_x"),
                            m_config->opt_float("wipe_tower_y"));
            wti.rotation = (M_PI/180.) * m_config->opt_float("wipe_tower_rotation_angle");
            const BoundingBoxf3& bb = vol->bounding_box;
            wti.bb_size = Vec2d(bb.size()(0), bb.size()(1));
            break;
        }
    }
    return wti;
}


void GLCanvas3D::arrange_wipe_tower(const arr::WipeTowerInfo& wti) const
{
    if (wti.is_wipe_tower) {
        DynamicPrintConfig cfg;
        cfg.opt<ConfigOptionFloat>("wipe_tower_x", true)->value = wti.pos(0);
        cfg.opt<ConfigOptionFloat>("wipe_tower_y", true)->value = wti.pos(1);
        cfg.opt<ConfigOptionFloat>("wipe_tower_rotation_angle", true)->value = (180./M_PI) * wti.rotation;
        wxGetApp().get_tab(Preset::TYPE_PRINT)->load_config(cfg);
    }
}


Linef3 GLCanvas3D::mouse_ray(const Point& mouse_pos)
{
    float z0 = 0.0f;
    float z1 = 1.0f;
    return Linef3(_mouse_to_3d(mouse_pos, &z0), _mouse_to_3d(mouse_pos, &z1));
}

double GLCanvas3D::get_size_proportional_to_max_bed_size(double factor) const
{
    return factor * m_bed.get_bounding_box(false).max_size();
}

void GLCanvas3D::set_cursor(ECursorType type)
{
    if ((m_canvas != nullptr) && (m_cursor_type != type))
    {
        switch (type)
        {
        case Standard: { m_canvas->SetCursor(*wxSTANDARD_CURSOR); break; }
        case Cross: { m_canvas->SetCursor(*wxCROSS_CURSOR); break; }
        }

        m_cursor_type = type;
    }
}

void GLCanvas3D::msw_rescale()
{
    m_warning_texture.msw_rescale(*this);
}

bool GLCanvas3D::_is_shown_on_screen() const
{
    return (m_canvas != nullptr) ? m_canvas->IsShownOnScreen() : false;
}

// Getter for the const char*[]
static bool string_getter(const bool is_undo, int idx, const char** out_text)
{
    return wxGetApp().plater()->undo_redo_string_getter(is_undo, idx, out_text);
}

void GLCanvas3D::_render_undo_redo_stack(const bool is_undo, float pos_x)
{
    const wxString& stack_name = _(is_undo ? L("Undo") : L("Redo"));
    ImGuiWrapper* imgui = wxGetApp().imgui();

    const float x = pos_x * (float)get_camera().get_zoom() + 0.5f * (float)get_canvas_size().get_width();
    imgui->set_next_window_pos(x, m_toolbar.get_height(), ImGuiCond_Always, 0.5f, 0.0f);
    imgui->set_next_window_bg_alpha(0.5f);
    imgui->begin(wxString::Format(_(L("%s Stack")), stack_name),
                 ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse);

    int hovered = m_imgui_undo_redo_hovered_pos;
    int selected = -1;
    const float em = static_cast<float>(wxGetApp().em_unit());

    if (imgui->undo_redo_list(ImVec2(12 * em, 20 * em), is_undo, &string_getter, hovered, selected))
        m_imgui_undo_redo_hovered_pos = hovered;
    else
        m_imgui_undo_redo_hovered_pos = -1;

    if (selected >= 0)
        is_undo ? wxGetApp().plater()->undo_to(selected) : wxGetApp().plater()->redo_to(selected);

    imgui->text(wxString::Format(_(L("%s %d Action")), stack_name, hovered + 1));

    imgui->end();
}

bool GLCanvas3D::_init_toolbar()
{
    if (!m_toolbar.is_enabled())
        return true;

#if !ENABLE_SVG_ICONS
    ItemsIconsTexture::Metadata icons_data;
    icons_data.filename = "toolbar.png";
    icons_data.icon_size = 37;
#endif // !ENABLE_SVG_ICONS

    BackgroundTexture::Metadata background_data;
    background_data.filename = "toolbar_background.png";
    background_data.left = 16;
    background_data.top = 16;
    background_data.right = 16;
    background_data.bottom = 16;

#if ENABLE_SVG_ICONS
    if (!m_toolbar.init(background_data))
#else
    if (!m_toolbar.init(icons_data, background_data))
#endif // ENABLE_SVG_ICONS
    {
        // unable to init the toolbar texture, disable it
        m_toolbar.set_enabled(false);
        return true;
    }

//    m_toolbar.set_layout_type(GLToolbar::Layout::Vertical);
    m_toolbar.set_layout_type(GLToolbar::Layout::Horizontal);
    m_toolbar.set_layout_orientation(GLToolbar::Layout::Top);
    m_toolbar.set_border(5.0f);
    m_toolbar.set_separator_size(5);
    m_toolbar.set_gap_size(2);

    GLToolbarItem::Data item;

    item.name = "add";
#if ENABLE_SVG_ICONS
    item.icon_filename = "add.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Add...")) + " [" + GUI::shortkey_ctrl_prefix() + "I]";
    item.sprite_id = 0;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_ADD)); };
    if (!m_toolbar.add_item(item))
        return false;

    item.name = "delete";
#if ENABLE_SVG_ICONS
    item.icon_filename = "remove.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Delete")) + " [Del]";
    item.sprite_id = 1;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_DELETE)); };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_delete(); };
    if (!m_toolbar.add_item(item))
        return false;

    item.name = "deleteall";
#if ENABLE_SVG_ICONS
    item.icon_filename = "delete_all.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Delete all")) + " [" + GUI::shortkey_ctrl_prefix() + "Del]";
    item.sprite_id = 2;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_DELETE_ALL)); };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_delete_all(); };
    if (!m_toolbar.add_item(item))
        return false;

    item.name = "arrange";
#if ENABLE_SVG_ICONS
    item.icon_filename = "arrange.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Arrange")) + " [A]";
    item.sprite_id = 3;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_ARRANGE)); };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_arrange(); };
    if (!m_toolbar.add_item(item))
        return false;

    if (!m_toolbar.add_separator())
        return false;

    item.name = "copy";
#if ENABLE_SVG_ICONS
    item.icon_filename = "copy.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Copy")) + " [" + GUI::shortkey_ctrl_prefix() + "C]";
    item.sprite_id = 4;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_COPY)); };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_copy_to_clipboard(); };
    if (!m_toolbar.add_item(item))
        return false;

    item.name = "paste";
#if ENABLE_SVG_ICONS
    item.icon_filename = "paste.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Paste")) + " [" + GUI::shortkey_ctrl_prefix() + "V]";
    item.sprite_id = 5;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_PASTE)); };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_paste_from_clipboard(); };
    if (!m_toolbar.add_item(item))
        return false;

    if (!m_toolbar.add_separator())
        return false;

    item.name = "more";
#if ENABLE_SVG_ICONS
    item.icon_filename = "instance_add.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Add instance")) + " [+]";
    item.sprite_id = 6;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_MORE)); };
    item.visibility_callback = []()->bool { return wxGetApp().get_mode() != comSimple; };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_increase_instances(); };

    if (!m_toolbar.add_item(item))
        return false;

    item.name = "fewer";
#if ENABLE_SVG_ICONS
    item.icon_filename = "instance_remove.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Remove instance")) + " [-]";
    item.sprite_id = 7;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_FEWER)); };
    item.visibility_callback = []()->bool { return wxGetApp().get_mode() != comSimple; };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_decrease_instances(); };
    if (!m_toolbar.add_item(item))
        return false;

    if (!m_toolbar.add_separator())
        return false;

    item.name = "splitobjects";
#if ENABLE_SVG_ICONS
    item.icon_filename = "split_objects.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Split to objects"));
    item.sprite_id = 8;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_SPLIT_OBJECTS)); };
    item.visibility_callback = GLToolbarItem::Default_Visibility_Callback;
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_split_to_objects(); };
    if (!m_toolbar.add_item(item))
        return false;

    item.name = "splitvolumes";
#if ENABLE_SVG_ICONS
    item.icon_filename = "split_parts.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Split to parts"));
    item.sprite_id = 9;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_SPLIT_VOLUMES)); };
    item.visibility_callback = []()->bool { return wxGetApp().get_mode() != comSimple; };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_split_to_volumes(); };
    if (!m_toolbar.add_item(item))
        return false;

    if (!m_toolbar.add_separator())
        return false;

    item.name = "layersediting";
#if ENABLE_SVG_ICONS
    item.icon_filename = "layers_white.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Layers editing"));
    item.sprite_id = 10;
    item.left_toggable = true;
    item.left_action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_LAYERSEDITING)); };
    item.visibility_callback = [this]()->bool { return m_process->current_printer_technology() == ptFFF; };
    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_layers_editing(); };
    if (!m_toolbar.add_item(item))
        return false;

    if (!m_toolbar.add_separator())
        return false;

    item.name = "undo";
#if ENABLE_SVG_ICONS
    item.icon_filename = "undo_toolbar.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Undo")) + " [" + GUI::shortkey_ctrl_prefix() + "Z]";
    item.sprite_id = 11;
    item.left_toggable = false;
    item.right_toggable = true;
    item.left_action_callback = [this]() { post_event(SimpleEvent(EVT_GLCANVAS_UNDO)); };
    item.right_action_callback  = [this]() { m_imgui_undo_redo_hovered_pos = -1; };
    item.visibility_callback = []()->bool { return true; };
    item.enabling_callback = [this]()->bool { return wxGetApp().plater()->can_undo(); };
    item.right_render_callback = [this](float left, float right, float, float) { if (m_canvas != nullptr) _render_undo_redo_stack(true, 0.5f * (left + right)); };
    if (!m_toolbar.add_item(item))
        return false;

    item.name = "redo";
#if ENABLE_SVG_ICONS
    item.icon_filename = "redo_toolbar.svg";
#endif // ENABLE_SVG_ICONS
    item.tooltip = _utf8(L("Redo")) + " [" + GUI::shortkey_ctrl_prefix() + "Y]";
    item.sprite_id = 12;
    item.left_action_callback = [this]() { post_event(SimpleEvent(EVT_GLCANVAS_REDO)); };
    item.right_action_callback = [this]() { m_imgui_undo_redo_hovered_pos = -1; };
    item.enabling_callback = [this]()->bool { return wxGetApp().plater()->can_redo(); };
    item.right_render_callback = [this](float left, float right, float, float) { if (m_canvas != nullptr) _render_undo_redo_stack(false, 0.5f * (left + right)); };
    if (!m_toolbar.add_item(item))
        return false;

    return true;
}

bool GLCanvas3D::_set_current()
{
    if (_is_shown_on_screen() && (m_context != nullptr)) {
        return m_canvas->SetCurrent(*m_context);
    }

    return false;
}

void GLCanvas3D::_resize(unsigned int w, unsigned int h)
{
    if ((m_canvas == nullptr) && (m_context == nullptr))
        return;

    auto *imgui = wxGetApp().imgui();
    imgui->set_display_size((float)w, (float)h);
    const float font_size = 1.5f * wxGetApp().em_unit();
#if ENABLE_RETINA_GL
    imgui->set_scaling(font_size, 1.0f, m_retina_helper->get_scale_factor());
#else
    imgui->set_scaling(font_size, m_canvas->GetContentScaleFactor(), 1.0f);
#endif

    // ensures that this canvas is current
    _set_current();

    // updates camera
    m_camera.apply_viewport(0, 0, w, h);

    m_dirty = false;
}

BoundingBoxf3 GLCanvas3D::_max_bounding_box(bool include_bed_model) const
{
    BoundingBoxf3 bb = volumes_bounding_box();
    bb.merge(m_bed.get_bounding_box(include_bed_model));
    return bb;
}

void GLCanvas3D::_zoom_to_box(const BoundingBoxf3& box)
{
    const Size& cnv_size = get_canvas_size();
    m_camera.zoom_to_box(box, cnv_size.get_width(), cnv_size.get_height());
    m_dirty = true;
}

void GLCanvas3D::_refresh_if_shown_on_screen()
{
    if (_is_shown_on_screen())
    {
        const Size& cnv_size = get_canvas_size();
        _resize((unsigned int)cnv_size.get_width(), (unsigned int)cnv_size.get_height());

        // Because of performance problems on macOS, where PaintEvents are not delivered
        // frequently enough, we call render() here directly when we can.
        render();
    }
}

void GLCanvas3D::_picking_pass() const
{
    if (m_picking_enabled && !m_mouse.dragging && (m_mouse.position != Vec2d(DBL_MAX, DBL_MAX)))
    {
        m_hover_volume_idxs.clear();

        // Render the object for picking.
        // FIXME This cannot possibly work in a multi - sampled context as the color gets mangled by the anti - aliasing.
        // Better to use software ray - casting on a bounding - box hierarchy.

        if (m_multisample_allowed)
            glsafe(::glDisable(GL_MULTISAMPLE));

        glsafe(::glDisable(GL_BLEND));
        glsafe(::glEnable(GL_DEPTH_TEST));

        glsafe(::glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));

        m_camera_clipping_plane = m_gizmos.get_sla_clipping_plane();
        if (m_camera_clipping_plane.is_active()) {
            ::glClipPlane(GL_CLIP_PLANE0, (GLdouble*)m_camera_clipping_plane.get_data());
            ::glEnable(GL_CLIP_PLANE0);
        }
        _render_volumes_for_picking();
        if (m_camera_clipping_plane.is_active())
            ::glDisable(GL_CLIP_PLANE0);

        m_gizmos.render_current_gizmo_for_picking_pass(m_selection);

        if (m_multisample_allowed)
            glsafe(::glEnable(GL_MULTISAMPLE));

        int volume_id = -1;

        GLubyte color[4] = { 0, 0, 0, 0 };
        const Size& cnv_size = get_canvas_size();
        bool inside = (0 <= m_mouse.position(0)) && (m_mouse.position(0) < cnv_size.get_width()) && (0 <= m_mouse.position(1)) && (m_mouse.position(1) < cnv_size.get_height());
        if (inside)
        {
            glsafe(::glReadPixels(m_mouse.position(0), cnv_size.get_height() - m_mouse.position(1) - 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, (void*)color));
            volume_id = color[0] + (color[1] << 8) + (color[2] << 16);
        }
        if ((0 <= volume_id) && (volume_id < (int)m_volumes.volumes.size()))
        {
            m_hover_volume_idxs.push_back(volume_id);
            m_gizmos.set_hover_id(-1);
        }
        else
            m_gizmos.set_hover_id(inside && volume_id <= GLGizmoBase::BASE_ID ? (GLGizmoBase::BASE_ID - volume_id) : -1);

        _update_volumes_hover_state();
    }
}

void GLCanvas3D::_rectangular_selection_picking_pass() const
{
    m_gizmos.set_hover_id(-1);

    std::set<int> idxs;

    if (m_picking_enabled)
    {
        if (m_multisample_allowed)
            glsafe(::glDisable(GL_MULTISAMPLE));

        glsafe(::glDisable(GL_BLEND));
        glsafe(::glEnable(GL_DEPTH_TEST));

        glsafe(::glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));

        _render_volumes_for_picking();

        if (m_multisample_allowed)
            glsafe(::glEnable(GL_MULTISAMPLE));

        int width = std::max((int)m_rectangle_selection.get_width(), 1);
        int height = std::max((int)m_rectangle_selection.get_height(), 1);
        int px_count = width * height;

        int left = (int)m_rectangle_selection.get_left();
        int top = get_canvas_size().get_height() - (int)m_rectangle_selection.get_top();
        if ((left >= 0) && (top >= 0))
        {
#define USE_PARALLEL 1
#if USE_PARALLEL
            struct Pixel
            {
                std::array<GLubyte, 4> data;
                int id() const { return data[0] + (data[1] << 8) + (data[2] << 16); }
            };

            std::vector<Pixel> frame(px_count);
            glsafe(::glReadPixels(left, top, width, height, GL_RGBA, GL_UNSIGNED_BYTE, (void*)frame.data()));

            tbb::spin_mutex mutex;
            tbb::parallel_for(tbb::blocked_range<size_t>(0, frame.size(), (size_t)width),
                [this, &frame, &idxs, &mutex](const tbb::blocked_range<size_t>& range) {
                for (size_t i = range.begin(); i < range.end(); ++i)
                {
                    int volume_id = frame[i].id();
                    if ((0 <= volume_id) && (volume_id < (int)m_volumes.volumes.size()))
                    {
                        mutex.lock();
                        idxs.insert(volume_id);
                        mutex.unlock();
                    }
                }
            }
            );
#else
            std::vector<GLubyte> frame(4 * px_count);
            glsafe(::glReadPixels(left, top, width, height, GL_RGBA, GL_UNSIGNED_BYTE, (void*)frame.data()));

            for (int i = 0; i < px_count; ++i)
            {
                int px_id = 4 * i;
                int volume_id = frame[px_id] + (frame[px_id + 1] << 8) + (frame[px_id + 2] << 16);
                if ((0 <= volume_id) && (volume_id < (int)m_volumes.volumes.size()))
                    idxs.insert(volume_id);
            }
#endif // USE_PARALLEL
        }
    }

    m_hover_volume_idxs.assign(idxs.begin(), idxs.end());
    _update_volumes_hover_state();
}

void GLCanvas3D::_render_background() const
{
    glsafe(::glPushMatrix());
    glsafe(::glLoadIdentity());
    glsafe(::glMatrixMode(GL_PROJECTION));
    glsafe(::glPushMatrix());
    glsafe(::glLoadIdentity());

    // Draws a bottom to top gradient over the complete screen.
    glsafe(::glDisable(GL_DEPTH_TEST));

    ::glBegin(GL_QUADS);
    if (m_dynamic_background_enabled && _is_any_volume_outside())
        ::glColor3fv(ERROR_BG_DARK_COLOR);
    else
        ::glColor3fv(DEFAULT_BG_DARK_COLOR);

    ::glVertex2f(-1.0f, -1.0f);
    ::glVertex2f(1.0f, -1.0f);

    if (m_dynamic_background_enabled && _is_any_volume_outside())
        ::glColor3fv(ERROR_BG_LIGHT_COLOR);
    else
        ::glColor3fv(DEFAULT_BG_LIGHT_COLOR);

    ::glVertex2f(1.0f, 1.0f);
    ::glVertex2f(-1.0f, 1.0f);
    glsafe(::glEnd());

    glsafe(::glEnable(GL_DEPTH_TEST));

    glsafe(::glPopMatrix());
    glsafe(::glMatrixMode(GL_MODELVIEW));
    glsafe(::glPopMatrix());
}

void GLCanvas3D::_render_bed(float theta) const
{
    float scale_factor = 1.0;
#if ENABLE_RETINA_GL
    scale_factor = m_retina_helper->get_scale_factor();
#endif // ENABLE_RETINA_GL
    m_bed.render(const_cast<GLCanvas3D*>(this), theta, m_use_VBOs, scale_factor);
}

void GLCanvas3D::_render_axes() const
{
    m_bed.render_axes();
}



void GLCanvas3D::_render_objects() const
{
    if (m_volumes.empty())
        return;

    glsafe(::glEnable(GL_LIGHTING));
    glsafe(::glEnable(GL_DEPTH_TEST));

    m_camera_clipping_plane = m_gizmos.get_sla_clipping_plane();

    if (m_use_VBOs)
    {
        if (m_picking_enabled)
        {
            // Update the layer editing selection to the first object selected, update the current object maximum Z.
            const_cast<LayersEditing&>(m_layers_editing).select_object(*m_model, this->is_layers_editing_enabled() ? m_selection.get_object_idx() : -1);

            if (m_config != nullptr)
            {
                const BoundingBoxf3& bed_bb = m_bed.get_bounding_box(false);
                m_volumes.set_print_box((float)bed_bb.min(0), (float)bed_bb.min(1), 0.0f, (float)bed_bb.max(0), (float)bed_bb.max(1), (float)m_config->opt_float("max_print_height"));
                m_volumes.check_outside_state(m_config, nullptr);
            }
        }

        if (m_use_clipping_planes)
            m_volumes.set_z_range(-m_clipping_planes[0].get_data()[3], m_clipping_planes[1].get_data()[3]);
        else
            m_volumes.set_z_range(-FLT_MAX, FLT_MAX);

        m_volumes.set_clipping_plane(m_camera_clipping_plane.get_data());

        m_shader.start_using();
        if (m_picking_enabled && !m_gizmos.is_dragging() && m_layers_editing.is_enabled() && (m_layers_editing.last_object_id != -1) && (m_layers_editing.object_max_z() > 0.0f)) {
            int object_id = m_layers_editing.last_object_id;
            m_volumes.render_VBOs(GLVolumeCollection::Opaque, false, m_camera.get_view_matrix(), [object_id](const GLVolume &volume) {
                // Which volume to paint without the layer height profile shader?
                return volume.is_active && (volume.is_modifier || volume.composite_id.object_id != object_id);
            });
            // Let LayersEditing handle rendering of the active object using the layer height profile shader.
            m_layers_editing.render_volumes(*this, this->m_volumes);
        } else {
            // do not cull backfaces to show broken geometry, if any
            m_volumes.render_VBOs(GLVolumeCollection::Opaque, m_picking_enabled, m_camera.get_view_matrix(), [this](const GLVolume& volume) {
                return (m_render_sla_auxiliaries || volume.composite_id.volume_id >= 0);
            });
        }
        m_volumes.render_VBOs(GLVolumeCollection::Transparent, false, m_camera.get_view_matrix());
        m_shader.stop_using();
    }
    else
    {
        ::glClipPlane(GL_CLIP_PLANE0, (GLdouble*)m_camera_clipping_plane.get_data());
        ::glEnable(GL_CLIP_PLANE0);

        if (m_use_clipping_planes)
        {
            glsafe(::glClipPlane(GL_CLIP_PLANE1, (GLdouble*)m_clipping_planes[0].get_data()));
            glsafe(::glEnable(GL_CLIP_PLANE1));
            glsafe(::glClipPlane(GL_CLIP_PLANE2, (GLdouble*)m_clipping_planes[1].get_data()));
            glsafe(::glEnable(GL_CLIP_PLANE2));
        }
        

        // do not cull backfaces to show broken geometry, if any
        m_volumes.render_legacy(GLVolumeCollection::Opaque, m_picking_enabled, m_camera.get_view_matrix(), [this](const GLVolume& volume) {
            return (m_render_sla_auxiliaries || volume.composite_id.volume_id >= 0);
        });
        m_volumes.render_legacy(GLVolumeCollection::Transparent, false, m_camera.get_view_matrix());

        ::glDisable(GL_CLIP_PLANE0);

        if (m_use_clipping_planes)
        {
            glsafe(::glDisable(GL_CLIP_PLANE1));
            glsafe(::glDisable(GL_CLIP_PLANE2));
        }
    }
    
    m_camera_clipping_plane = ClippingPlane::ClipsNothing();
    glsafe(::glDisable(GL_LIGHTING));
}

void GLCanvas3D::_render_selection() const
{
    float scale_factor = 1.0;
#if ENABLE_RETINA_GL
    scale_factor = m_retina_helper->get_scale_factor();
#endif

    if (!m_gizmos.is_running())
        m_selection.render(scale_factor);
}

#if ENABLE_RENDER_SELECTION_CENTER
void GLCanvas3D::_render_selection_center() const
{
    m_selection.render_center(m_gizmos.is_dragging());
}
#endif // ENABLE_RENDER_SELECTION_CENTER

void GLCanvas3D::_render_overlays() const
{
    glsafe(::glDisable(GL_DEPTH_TEST));
    glsafe(::glPushMatrix());
    glsafe(::glLoadIdentity());
    // ensure that the textures are renderered inside the frustrum
    glsafe(::glTranslated(0.0, 0.0, -(m_camera.get_near_z() + 0.5)));
    // ensure that the overlay fits the frustrum near z plane
    double gui_scale = m_camera.get_gui_scale();
    glsafe(::glScaled(gui_scale, gui_scale, 1.0));

    _render_gizmos_overlay();
    _render_warning_texture();
    _render_legend_texture();
#if !ENABLE_SVG_ICONS
    _resize_toolbars();
#endif // !ENABLE_SVG_ICONS
    _render_toolbar();
    _render_view_toolbar();

    if ((m_layers_editing.last_object_id >= 0) && (m_layers_editing.object_max_z() > 0.0f))
        m_layers_editing.render_overlay(*this);

    glsafe(::glPopMatrix());
}

void GLCanvas3D::_render_warning_texture() const
{
    m_warning_texture.render(*this);
}

void GLCanvas3D::_render_legend_texture() const
{
    if (!m_legend_texture_enabled)
        return;

    m_legend_texture.render(*this);
}

void GLCanvas3D::_render_volumes_for_picking() const
{
    static const GLfloat INV_255 = 1.0f / 255.0f;

    // do not cull backfaces to show broken geometry, if any
    glsafe(::glDisable(GL_CULL_FACE));

    glsafe(::glEnable(GL_BLEND));
    glsafe(::glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));

    glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
    glsafe(::glEnableClientState(GL_NORMAL_ARRAY));

    const Transform3d& view_matrix = m_camera.get_view_matrix();
    GLVolumeWithIdAndZList to_render = volumes_to_render(m_volumes.volumes, GLVolumeCollection::Opaque, view_matrix);
    for (const GLVolumeWithIdAndZ& volume : to_render)
    {
        // Object picking mode. Render the object with a color encoding the object index.
        unsigned int r = (volume.second.first & 0x000000FF) >> 0;
        unsigned int g = (volume.second.first & 0x0000FF00) >> 8;
        unsigned int b = (volume.second.first & 0x00FF0000) >> 16;
        glsafe(::glColor3f((GLfloat)r * INV_255, (GLfloat)g * INV_255, (GLfloat)b * INV_255));

        if (!volume.first->disabled && ((volume.first->composite_id.volume_id >= 0) || m_render_sla_auxiliaries))
            volume.first->render();
    }

    to_render = volumes_to_render(m_volumes.volumes, GLVolumeCollection::Transparent, view_matrix);
    for (const GLVolumeWithIdAndZ& volume : to_render)
    {
        // Object picking mode. Render the object with a color encoding the object index.
        unsigned int r = (volume.second.first & 0x000000FF) >> 0;
        unsigned int g = (volume.second.first & 0x0000FF00) >> 8;
        unsigned int b = (volume.second.first & 0x00FF0000) >> 16;
        glsafe(::glColor3f((GLfloat)r * INV_255, (GLfloat)g * INV_255, (GLfloat)b * INV_255));

        if (!volume.first->disabled && ((volume.first->composite_id.volume_id >= 0) || m_render_sla_auxiliaries))
            volume.first->render();
    }

    glsafe(::glDisableClientState(GL_NORMAL_ARRAY));
    glsafe(::glDisableClientState(GL_VERTEX_ARRAY));
    glsafe(::glDisable(GL_BLEND));

    glsafe(::glEnable(GL_CULL_FACE));
}

void GLCanvas3D::_render_current_gizmo() const
{
    m_gizmos.render_current_gizmo(m_selection);
}

void GLCanvas3D::_render_gizmos_overlay() const
{
#if ENABLE_RETINA_GL
//     m_gizmos.set_overlay_scale(m_retina_helper->get_scale_factor());
    const float scale = m_retina_helper->get_scale_factor()*wxGetApp().toolbar_icon_scale();
    m_gizmos.set_overlay_scale(scale); //! #ys_FIXME_experiment
#else
//     m_gizmos.set_overlay_scale(m_canvas->GetContentScaleFactor());
//     m_gizmos.set_overlay_scale(wxGetApp().em_unit()*0.1f);
    const float size = int(GLGizmosManager::Default_Icons_Size*wxGetApp().toolbar_icon_scale());
    m_gizmos.set_overlay_icon_size(size); //! #ys_FIXME_experiment
#endif /* __WXMSW__ */

    m_gizmos.render_overlay(*this, m_selection);
}

void GLCanvas3D::_render_toolbar() const
{
#if ENABLE_SVG_ICONS
#if ENABLE_RETINA_GL
//     m_toolbar.set_scale(m_retina_helper->get_scale_factor());
    const float scale = m_retina_helper->get_scale_factor() * wxGetApp().toolbar_icon_scale(true);
    m_toolbar.set_scale(scale); //! #ys_FIXME_experiment
#else
//     m_toolbar.set_scale(m_canvas->GetContentScaleFactor());
//     m_toolbar.set_scale(wxGetApp().em_unit()*0.1f);
    const float size = int(GLToolbar::Default_Icons_Size * wxGetApp().toolbar_icon_scale(true));
    m_toolbar.set_icons_size(size); //! #ys_FIXME_experiment
#endif // ENABLE_RETINA_GL

    Size cnv_size = get_canvas_size();
    float zoom = (float)m_camera.get_zoom();
    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;

    GLToolbar::Layout::EOrientation orientation = m_toolbar.get_layout_orientation();

    float top = 0.0f;
    float left = 0.0f;
    switch (m_toolbar.get_layout_type())
    {
    default:
    case GLToolbar::Layout::Horizontal:
    {
        // centers the toolbar on the top edge of the 3d scene
        if (orientation == GLToolbar::Layout::Top)
        {
            top = 0.5f * (float)cnv_size.get_height() * inv_zoom;
            left = -0.5f * m_toolbar.get_width() * inv_zoom;
        }
        else
        {
            top = (-0.5f * (float)cnv_size.get_height() + m_view_toolbar.get_height()) * inv_zoom;
            left = -0.5f * m_toolbar.get_width() * inv_zoom;
        }
        break;
    }
    case GLToolbar::Layout::Vertical:
    {
        // centers the toolbar on the right edge of the 3d scene
        if (orientation == GLToolbar::Layout::Left)
        {
            top = 0.5f * m_toolbar.get_height() * inv_zoom;
            left = (-0.5f * (float)cnv_size.get_width()) * inv_zoom;
        }
        else
        {
            top = 0.5f * m_toolbar.get_height() * inv_zoom;
            left = (0.5f * (float)cnv_size.get_width() - m_toolbar.get_width()) * inv_zoom;
        }
        break;
    }
    }
    m_toolbar.set_position(top, left);
#else
#if ENABLE_RETINA_GL
    m_toolbar.set_icons_scale(m_retina_helper->get_scale_factor());
#else
    m_toolbar.set_icons_scale(m_canvas->GetContentScaleFactor());
#endif /* __WXMSW__ */
#endif // ENABLE_SVG_ICONS

    m_toolbar.render(*this);
}

void GLCanvas3D::_render_view_toolbar() const
{
#if ENABLE_SVG_ICONS
#if ENABLE_RETINA_GL
//     m_view_toolbar.set_scale(m_retina_helper->get_scale_factor());
    const float scale = m_retina_helper->get_scale_factor() * wxGetApp().toolbar_icon_scale();
    m_view_toolbar.set_scale(scale); //! #ys_FIXME_experiment
#else
//     m_view_toolbar.set_scale(m_canvas->GetContentScaleFactor());
//     m_view_toolbar.set_scale(wxGetApp().em_unit()*0.1f);
    const float size = int(GLGizmosManager::Default_Icons_Size * wxGetApp().toolbar_icon_scale());
    m_view_toolbar.set_icons_size(size); //! #ys_FIXME_experiment
#endif // ENABLE_RETINA_GL

    Size cnv_size = get_canvas_size();
    float zoom = (float)m_camera.get_zoom();
    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;

    // places the toolbar on the bottom-left corner of the 3d scene
    float top = (-0.5f * (float)cnv_size.get_height() + m_view_toolbar.get_height()) * inv_zoom;
    float left = -0.5f * (float)cnv_size.get_width() * inv_zoom;
    m_view_toolbar.set_position(top, left);
#else
#if ENABLE_RETINA_GL
    m_view_toolbar.set_icons_scale(m_retina_helper->get_scale_factor());
#else
    m_view_toolbar.set_icons_scale(m_canvas->GetContentScaleFactor());
#endif /* __WXMSW__ */
#endif // ENABLE_SVG_ICONS
    m_view_toolbar.render(*this);
}

#if ENABLE_SHOW_CAMERA_TARGET
void GLCanvas3D::_render_camera_target() const
{
    double half_length = 5.0;

    glsafe(::glDisable(GL_DEPTH_TEST));

    glsafe(::glLineWidth(2.0f));
    ::glBegin(GL_LINES);
    const Vec3d& target = m_camera.get_target();
    // draw line for x axis
    ::glColor3f(1.0f, 0.0f, 0.0f);
    ::glVertex3d(target(0) - half_length, target(1), target(2));
    ::glVertex3d(target(0) + half_length, target(1), target(2));
    // draw line for y axis
    ::glColor3f(0.0f, 1.0f, 0.0f);
    ::glVertex3d(target(0), target(1) - half_length, target(2));
    ::glVertex3d(target(0), target(1) + half_length, target(2));
    // draw line for z axis
    ::glColor3f(0.0f, 0.0f, 1.0f);
    ::glVertex3d(target(0), target(1), target(2) - half_length);
    ::glVertex3d(target(0), target(1), target(2) + half_length);
    glsafe(::glEnd());
}
#endif // ENABLE_SHOW_CAMERA_TARGET

void GLCanvas3D::_render_sla_slices() const
{
    if (!m_use_clipping_planes || wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA)
        return;

    const SLAPrint* print = this->sla_print();
    const PrintObjects& print_objects = print->objects();
    if (print_objects.empty())
        // nothing to render, return
        return;

    double clip_min_z = -m_clipping_planes[0].get_data()[3];
    double clip_max_z = m_clipping_planes[1].get_data()[3];
    for (unsigned int i = 0; i < (unsigned int)print_objects.size(); ++i)
    {
        const SLAPrintObject* obj = print_objects[i];

        if (!obj->is_step_done(slaposSliceSupports))
            continue;

        SlaCap::ObjectIdToTrianglesMap::iterator it_caps_bottom = m_sla_caps[0].triangles.find(i);
        SlaCap::ObjectIdToTrianglesMap::iterator it_caps_top    = m_sla_caps[1].triangles.find(i);
        {
			if (it_caps_bottom == m_sla_caps[0].triangles.end())
				it_caps_bottom = m_sla_caps[0].triangles.emplace(i, SlaCap::Triangles()).first;
            if (! m_sla_caps[0].matches(clip_min_z)) {
				m_sla_caps[0].z = clip_min_z;
                it_caps_bottom->second.object.clear();
                it_caps_bottom->second.supports.clear();
            }
            if (it_caps_top == m_sla_caps[1].triangles.end())
				it_caps_top = m_sla_caps[1].triangles.emplace(i, SlaCap::Triangles()).first;
            if (! m_sla_caps[1].matches(clip_max_z)) {
				m_sla_caps[1].z = clip_max_z;
                it_caps_top->second.object.clear();
                it_caps_top->second.supports.clear();
            }
        }
        Pointf3s &bottom_obj_triangles = it_caps_bottom->second.object;
        Pointf3s &bottom_sup_triangles = it_caps_bottom->second.supports;
        Pointf3s &top_obj_triangles    = it_caps_top->second.object;
        Pointf3s &top_sup_triangles    = it_caps_top->second.supports;

        if ((bottom_obj_triangles.empty() || bottom_sup_triangles.empty() || top_obj_triangles.empty() || top_sup_triangles.empty()) &&
            !obj->get_slice_index().empty())
        {
            double layer_height         = print->default_object_config().layer_height.value;
            double initial_layer_height = print->material_config().initial_layer_height.value;
            bool   left_handed          = obj->is_left_handed();

            coord_t key_zero = obj->get_slice_index().front().print_level();
            // Slice at the center of the slab starting at clip_min_z will be rendered for the lower plane.
            coord_t key_low  = coord_t((clip_min_z - initial_layer_height + layer_height) / SCALING_FACTOR) + key_zero;
            // Slice at the center of the slab ending at clip_max_z will be rendered for the upper plane.
            coord_t key_high = coord_t((clip_max_z - initial_layer_height) / SCALING_FACTOR) + key_zero;

            const SliceRecord& slice_low  = obj->closest_slice_to_print_level(key_low, coord_t(SCALED_EPSILON));
            const SliceRecord& slice_high = obj->closest_slice_to_print_level(key_high, coord_t(SCALED_EPSILON));

            // Offset to avoid OpenGL Z fighting between the object's horizontal surfaces and the triangluated surfaces of the cuts.
            double plane_shift_z = 0.002;

            if (slice_low.is_valid()) {
                const ExPolygons& obj_bottom = slice_low.get_slice(soModel);
                const ExPolygons& sup_bottom = slice_low.get_slice(soSupport);
                // calculate model bottom cap
                if (bottom_obj_triangles.empty() && !obj_bottom.empty())
                    bottom_obj_triangles = triangulate_expolygons_3d(obj_bottom, clip_min_z - plane_shift_z, ! left_handed);
                // calculate support bottom cap
                if (bottom_sup_triangles.empty() && !sup_bottom.empty())
                    bottom_sup_triangles = triangulate_expolygons_3d(sup_bottom, clip_min_z - plane_shift_z, ! left_handed);
            }

            if (slice_high.is_valid()) {
                const ExPolygons& obj_top = slice_high.get_slice(soModel);
                const ExPolygons& sup_top = slice_high.get_slice(soSupport);
                // calculate model top cap
                if (top_obj_triangles.empty() && !obj_top.empty())
                    top_obj_triangles = triangulate_expolygons_3d(obj_top, clip_max_z + plane_shift_z, left_handed);
                // calculate support top cap
                if (top_sup_triangles.empty() && !sup_top.empty())
                    top_sup_triangles = triangulate_expolygons_3d(sup_top, clip_max_z + plane_shift_z, left_handed);
            }
        }

        if (!bottom_obj_triangles.empty() || !top_obj_triangles.empty() || !bottom_sup_triangles.empty() || !top_sup_triangles.empty())
        {
			for (const SLAPrintObject::Instance& inst : obj->instances())
            {
                glsafe(::glPushMatrix());
                glsafe(::glTranslated(unscale<double>(inst.shift.x()), unscale<double>(inst.shift.y()), 0));
                glsafe(::glRotatef(Geometry::rad2deg(inst.rotation), 0.0, 0.0, 1.0));
				if (obj->is_left_handed())
                    // The polygons are mirrored by X.
                    glsafe(::glScalef(-1.0, 1.0, 1.0));
                glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
                glsafe(::glColor3f(1.0f, 0.37f, 0.0f));
				if (!bottom_obj_triangles.empty()) {
                    glsafe(::glVertexPointer(3, GL_DOUBLE, 0, (GLdouble*)bottom_obj_triangles.front().data()));
                    glsafe(::glDrawArrays(GL_TRIANGLES, 0, bottom_obj_triangles.size()));
				}
				if (! top_obj_triangles.empty()) {
                    glsafe(::glVertexPointer(3, GL_DOUBLE, 0, (GLdouble*)top_obj_triangles.front().data()));
                    glsafe(::glDrawArrays(GL_TRIANGLES, 0, top_obj_triangles.size()));
				}
                glsafe(::glColor3f(1.0f, 0.0f, 0.37f));
				if (! bottom_sup_triangles.empty()) {
                    glsafe(::glVertexPointer(3, GL_DOUBLE, 0, (GLdouble*)bottom_sup_triangles.front().data()));
                    glsafe(::glDrawArrays(GL_TRIANGLES, 0, bottom_sup_triangles.size()));
				}
				if (! top_sup_triangles.empty()) {
                    glsafe(::glVertexPointer(3, GL_DOUBLE, 0, (GLdouble*)top_sup_triangles.front().data()));
                    glsafe(::glDrawArrays(GL_TRIANGLES, 0, top_sup_triangles.size()));
				}
                glsafe(::glDisableClientState(GL_VERTEX_ARRAY));
                glsafe(::glPopMatrix());
            }
        }
    }
}

void GLCanvas3D::_render_selection_sidebar_hints() const
{
    m_selection.render_sidebar_hints(m_sidebar_field, m_shader);
}


void GLCanvas3D::_update_volumes_hover_state() const
{
    for (GLVolume* v : m_volumes.volumes)
    {
        v->hover = GLVolume::HS_None;
    }

    if (m_hover_volume_idxs.empty())
        return;

    bool ctrl_pressed = wxGetKeyState(WXK_CONTROL); // additive select/deselect
    bool shift_pressed = wxGetKeyState(WXK_SHIFT);  // select by rectangle
    bool alt_pressed = wxGetKeyState(WXK_ALT);      // deselect by rectangle

    if (alt_pressed && (shift_pressed || ctrl_pressed))
    {
        // illegal combinations of keys
        m_hover_volume_idxs.clear();
        return;
    }

    bool selection_modifiers_only = m_selection.is_empty() || m_selection.is_any_modifier();

    bool hover_modifiers_only = true;
    for (int i : m_hover_volume_idxs)
    {
        if (!m_volumes.volumes[i]->is_modifier)
        {
            hover_modifiers_only = false;
            break;
        }
    }

    std::set<std::pair<int, int>> hover_instances;
    for (int i : m_hover_volume_idxs)
    {
        const GLVolume& v = *m_volumes.volumes[i];
        hover_instances.insert(std::make_pair(v.object_idx(), v.instance_idx()));
    }

    bool hover_from_single_instance = hover_instances.size() == 1;

    if (hover_modifiers_only && !hover_from_single_instance)
    {
        // do not allow to select volumes from different instances
        m_hover_volume_idxs.clear();
        return;
    }

    for (int i : m_hover_volume_idxs)
    {
        GLVolume& volume = *m_volumes.volumes[i];
        if (volume.hover != GLVolume::HS_None)
            continue;

        bool deselect = volume.selected && ((ctrl_pressed && !shift_pressed) || alt_pressed);
        // (volume->is_modifier && !selection_modifiers_only && !is_ctrl_pressed) -> allows hovering on selected modifiers belonging to selection of type Instance
        bool select = (!volume.selected || (volume.is_modifier && !selection_modifiers_only && !ctrl_pressed)) && !alt_pressed;

        if (select || deselect)
        {
            bool as_volume =
                volume.is_modifier && hover_from_single_instance && !ctrl_pressed &&
                (
                (!deselect) ||
                (deselect && !m_selection.is_single_full_instance() && (volume.object_idx() == m_selection.get_object_idx()) && (volume.instance_idx() == m_selection.get_instance_idx()))
                );

            if (as_volume)
            {
                if (deselect)
                    volume.hover = GLVolume::HS_Deselect;
                else
                    volume.hover = GLVolume::HS_Select;
            }
            else
            {
                int object_idx = volume.object_idx();
                int instance_idx = volume.instance_idx();

                for (GLVolume* v : m_volumes.volumes)
                {
                    if ((v->object_idx() == object_idx) && (v->instance_idx() == instance_idx))
                    {
                        if (deselect)
                            v->hover = GLVolume::HS_Deselect;
                        else
                            v->hover = GLVolume::HS_Select;
                    }
                }
            }
        }
    }
}

void GLCanvas3D::_perform_layer_editing_action(wxMouseEvent* evt)
{
    int object_idx_selected = m_layers_editing.last_object_id;
    if (object_idx_selected == -1)
        return;

    // A volume is selected. Test, whether hovering over a layer thickness bar.
    if (evt != nullptr)
    {
        const Rect& rect = LayersEditing::get_bar_rect_screen(*this);
        float b = rect.get_bottom();
        m_layers_editing.last_z = m_layers_editing.object_max_z() * (b - evt->GetY() - 1.0f) / (b - rect.get_top());
        m_layers_editing.last_action = 
            evt->ShiftDown() ? (evt->RightIsDown() ? LAYER_HEIGHT_EDIT_ACTION_SMOOTH : LAYER_HEIGHT_EDIT_ACTION_REDUCE) : 
                               (evt->RightIsDown() ? LAYER_HEIGHT_EDIT_ACTION_INCREASE : LAYER_HEIGHT_EDIT_ACTION_DECREASE);
    }

    m_layers_editing.adjust_layer_height_profile();
    _refresh_if_shown_on_screen();

    // Automatic action on mouse down with the same coordinate.
    _start_timer();
}

Vec3d GLCanvas3D::_mouse_to_3d(const Point& mouse_pos, float* z)
{
    if (m_canvas == nullptr)
        return Vec3d(DBL_MAX, DBL_MAX, DBL_MAX);


    const std::array<int, 4>& viewport = m_camera.get_viewport();
    const Transform3d& modelview_matrix = m_camera.get_view_matrix();
    const Transform3d& projection_matrix = m_camera.get_projection_matrix();

    GLint y = viewport[3] - (GLint)mouse_pos(1);
    GLfloat mouse_z;
    if (z == nullptr)
        glsafe(::glReadPixels((GLint)mouse_pos(0), y, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, (void*)&mouse_z));
    else
        mouse_z = *z;

    GLdouble out_x, out_y, out_z;
    ::gluUnProject((GLdouble)mouse_pos(0), (GLdouble)y, (GLdouble)mouse_z, (GLdouble*)modelview_matrix.data(), (GLdouble*)projection_matrix.data(), (GLint*)viewport.data(), &out_x, &out_y, &out_z);
    return Vec3d((double)out_x, (double)out_y, (double)out_z);
}

Vec3d GLCanvas3D::_mouse_to_bed_3d(const Point& mouse_pos)
{
    return mouse_ray(mouse_pos).intersect_plane(0.0);
}

void GLCanvas3D::_start_timer()
{
    m_timer.Start(100, wxTIMER_CONTINUOUS);
}

void GLCanvas3D::_stop_timer()
{
    m_timer.Stop();
}

void GLCanvas3D::_load_print_toolpaths()
{
    const Print *print = this->fff_print();
    if (print == nullptr)
        return;

    if (!print->is_step_done(psSkirt) || !print->is_step_done(psBrim))
        return;

    if (!print->has_skirt() && (print->config().brim_width.value == 0))
        return;

    const float color[] = { 0.5f, 1.0f, 0.5f, 1.0f }; // greenish

    // number of skirt layers
    size_t total_layer_count = 0;
    for (const PrintObject* print_object : print->objects())
    {
        total_layer_count = std::max(total_layer_count, print_object->total_layer_count());
    }
    size_t skirt_height = print->has_infinite_skirt() ? total_layer_count : std::min<size_t>(print->config().skirt_height.value, total_layer_count);
    if ((skirt_height == 0) && (print->config().brim_width.value > 0))
        skirt_height = 1;

    // get first skirt_height layers (maybe this should be moved to a PrintObject method?)
    const PrintObject* object0 = print->objects().front();
    std::vector<float> print_zs;
    print_zs.reserve(skirt_height * 2);
    for (size_t i = 0; i < std::min(skirt_height, object0->layers().size()); ++i)
    {
        print_zs.push_back(float(object0->layers()[i]->print_z));
    }
    //FIXME why there are support layers?
    for (size_t i = 0; i < std::min(skirt_height, object0->support_layers().size()); ++i)
    {
        print_zs.push_back(float(object0->support_layers()[i]->print_z));
    }
    sort_remove_duplicates(print_zs);
    if (print_zs.size() > skirt_height)
        print_zs.erase(print_zs.begin() + skirt_height, print_zs.end());

    m_volumes.volumes.emplace_back(new GLVolume(color));
    GLVolume& volume = *m_volumes.volumes.back();
    for (size_t i = 0; i < skirt_height; ++i) {
        volume.print_zs.push_back(print_zs[i]);
        volume.offsets.push_back(volume.indexed_vertex_array.quad_indices.size());
        volume.offsets.push_back(volume.indexed_vertex_array.triangle_indices.size());
        if (i == 0)
            _3DScene::extrusionentity_to_verts(print->brim(), print_zs[i], Point(0, 0), volume);

        _3DScene::extrusionentity_to_verts(print->skirt(), print_zs[i], Point(0, 0), volume);
    }
    volume.bounding_box = volume.indexed_vertex_array.bounding_box();
    volume.indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);
}

void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, const std::vector<std::string>& str_tool_colors, const std::vector<double>& color_print_values)
{
    std::vector<float> tool_colors = _parse_colors(str_tool_colors);

    struct Ctxt
    {
        const Points                *shifted_copies;
        std::vector<const Layer*>    layers;
        bool                         has_perimeters;
        bool                         has_infill;
        bool                         has_support;
        const std::vector<float>*    tool_colors;
        const std::vector<double>*   color_print_values;

        // Number of vertices (each vertex is 6x4=24 bytes long)
        static const size_t          alloc_size_max() { return 131072; } // 3.15MB
        //        static const size_t          alloc_size_max    () { return 65536; } // 1.57MB 
        //        static const size_t          alloc_size_max    () { return 32768; } // 786kB
        static const size_t          alloc_size_reserve() { return alloc_size_max() * 2; }

        static const float*          color_perimeters() { static float color[4] = { 1.0f, 1.0f, 0.0f, 1.f }; return color; } // yellow
        static const float*          color_infill() { static float color[4] = { 1.0f, 0.5f, 0.5f, 1.f }; return color; } // redish
        static const float*          color_support() { static float color[4] = { 0.5f, 1.0f, 0.5f, 1.f }; return color; } // greenish

        // For cloring by a tool, return a parsed color.
        bool                         color_by_tool() const { return tool_colors != nullptr; }
        size_t                       number_tools()  const { return this->color_by_tool() ? tool_colors->size() / 4 : 0; }
        const float*                 color_tool(size_t tool) const { return tool_colors->data() + tool * 4; }

        // For coloring by a color_print(M600), return a parsed color.
        bool                         color_by_color_print() const { return color_print_values!=nullptr; }
        const size_t                 color_print_color_idx_by_layer_idx(const size_t layer_idx) const {
            auto it = std::lower_bound(color_print_values->begin(), color_print_values->end(), layers[layer_idx]->print_z + EPSILON);
            return (it - color_print_values->begin()) % number_tools();
        }
    } ctxt;

    ctxt.has_perimeters = print_object.is_step_done(posPerimeters);
    ctxt.has_infill = print_object.is_step_done(posInfill);
    ctxt.has_support = print_object.is_step_done(posSupportMaterial);
    ctxt.tool_colors = tool_colors.empty() ? nullptr : &tool_colors;
    ctxt.color_print_values = color_print_values.empty() ? nullptr : &color_print_values;

    ctxt.shifted_copies = &print_object.copies();

    // order layers by print_z
    {
        size_t nlayers = 0;
        if (ctxt.has_perimeters || ctxt.has_infill)
            nlayers = print_object.layers().size();
        if (ctxt.has_support)
            nlayers += print_object.support_layers().size();
        ctxt.layers.reserve(nlayers);
    }
    if (ctxt.has_perimeters || ctxt.has_infill)
        for (const Layer *layer : print_object.layers())
            ctxt.layers.push_back(layer);
    if (ctxt.has_support)
        for (const Layer *layer : print_object.support_layers())
            ctxt.layers.push_back(layer);
    std::sort(ctxt.layers.begin(), ctxt.layers.end(), [](const Layer *l1, const Layer *l2) { return l1->print_z < l2->print_z; });

    // Maximum size of an allocation block: 32MB / sizeof(float)
    BOOST_LOG_TRIVIAL(debug) << "Loading print object toolpaths in parallel - start";

    //FIXME Improve the heuristics for a grain size.
    size_t          grain_size = std::max(ctxt.layers.size() / 16, size_t(1));
    tbb::spin_mutex new_volume_mutex;
    auto            new_volume = [this, &new_volume_mutex](const float *color) -> GLVolume* {
        auto *volume = new GLVolume(color);
        new_volume_mutex.lock();
        m_volumes.volumes.emplace_back(volume);
        new_volume_mutex.unlock();
        return volume;
    };
    const size_t    volumes_cnt_initial = m_volumes.volumes.size();
    tbb::parallel_for(
        tbb::blocked_range<size_t>(0, ctxt.layers.size(), grain_size),
        [&ctxt, &new_volume](const tbb::blocked_range<size_t>& range) {
        GLVolumePtrs 		vols;
        std::vector<size_t>	color_print_layer_to_glvolume;
        auto                volume = [&ctxt, &vols, &color_print_layer_to_glvolume, &range](size_t layer_idx, int extruder, int feature) -> GLVolume& {
            return *vols[ctxt.color_by_color_print() ?
            	color_print_layer_to_glvolume[layer_idx - range.begin()] :
				ctxt.color_by_tool() ? 
					std::min<int>(ctxt.number_tools() - 1, std::max<int>(extruder - 1, 0)) : 
					feature
				];
        };
        if (ctxt.color_by_color_print()) {
        	// Create a map from the layer index to a GLVolume, which is initialized with the correct layer span color.
        	std::vector<int> color_print_tool_to_glvolume(ctxt.number_tools(), -1);
        	color_print_layer_to_glvolume.reserve(range.end() - range.begin());
        	vols.reserve(ctxt.number_tools());
	        for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++ idx_layer) {
	        	int idx_tool = (int)ctxt.color_print_color_idx_by_layer_idx(idx_layer);
	        	if (color_print_tool_to_glvolume[idx_tool] == -1) {
	        		color_print_tool_to_glvolume[idx_tool] = (int)vols.size();
	        		vols.emplace_back(new_volume(ctxt.color_tool(idx_tool)));
	        	}
	        	color_print_layer_to_glvolume.emplace_back(color_print_tool_to_glvolume[idx_tool]);
	        }
        }
        else if (ctxt.color_by_tool()) {
            for (size_t i = 0; i < ctxt.number_tools(); ++i)
                vols.emplace_back(new_volume(ctxt.color_tool(i)));
        }
        else
            vols = { new_volume(ctxt.color_perimeters()), new_volume(ctxt.color_infill()), new_volume(ctxt.color_support()) };
        for (GLVolume *vol : vols)
        	vol->indexed_vertex_array.reserve(ctxt.alloc_size_reserve());
        for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++ idx_layer) {
            const Layer *layer = ctxt.layers[idx_layer];
            for (GLVolume *vol : vols)
                if (vol->print_zs.empty() || vol->print_zs.back() != layer->print_z) {
                    vol->print_zs.push_back(layer->print_z);
                    vol->offsets.push_back(vol->indexed_vertex_array.quad_indices.size());
                    vol->offsets.push_back(vol->indexed_vertex_array.triangle_indices.size());
                }
            for (const Point &copy : *ctxt.shifted_copies) {
                for (const LayerRegion *layerm : layer->regions()) {
                    if (ctxt.has_perimeters)
                        _3DScene::extrusionentity_to_verts(layerm->perimeters, float(layer->print_z), copy,
                        	volume(idx_layer, layerm->region()->config().perimeter_extruder.value, 0));
                    if (ctxt.has_infill) {
                        for (const ExtrusionEntity *ee : layerm->fills.entities) {
                            // fill represents infill extrusions of a single island.
                            const auto *fill = dynamic_cast<const ExtrusionEntityCollection*>(ee);
                            if (! fill->entities.empty())
                                _3DScene::extrusionentity_to_verts(*fill, float(layer->print_z), copy,
	                                volume(idx_layer, 
		                                is_solid_infill(fill->entities.front()->role()) ?
			                                layerm->region()->config().solid_infill_extruder :
			                                layerm->region()->config().infill_extruder,
		                                1));
                        }
                    }
                }
                if (ctxt.has_support) {
                    const SupportLayer *support_layer = dynamic_cast<const SupportLayer*>(layer);
                    if (support_layer) {
                        for (const ExtrusionEntity *extrusion_entity : support_layer->support_fills.entities)
                            _3DScene::extrusionentity_to_verts(extrusion_entity, float(layer->print_z), copy,
	                            volume(idx_layer, 
		                            (extrusion_entity->role() == erSupportMaterial) ?
			                            support_layer->object()->config().support_material_extruder :
			                            support_layer->object()->config().support_material_interface_extruder,
		                            2));
                    }
                }
            }
            // Ensure that no volume grows over the limits. If the volume is too large, allocate a new one.
	        for (size_t i = 0; i < vols.size(); ++i) {
	            GLVolume &vol = *vols[i];
	            if (vol.indexed_vertex_array.vertices_and_normals_interleaved.size() / 6 > ctxt.alloc_size_max()) {
	                // Store the vertex arrays and restart their containers, 
	                vols[i] = new_volume(vol.color);
	                GLVolume &vol_new = *vols[i];
	                // Assign the large pre-allocated buffers to the new GLVolume.
	                vol_new.indexed_vertex_array = std::move(vol.indexed_vertex_array);
	                // Copy the content back to the old GLVolume.
	                vol.indexed_vertex_array = vol_new.indexed_vertex_array;
	                // Finalize a bounding box of the old GLVolume.
	                vol.bounding_box = vol.indexed_vertex_array.bounding_box();
	                // Clear the buffers, but keep them pre-allocated.
	                vol_new.indexed_vertex_array.clear();
	                // Just make sure that clear did not clear the reserved memory.
	                vol_new.indexed_vertex_array.reserve(ctxt.alloc_size_reserve());
	            }
	        }
        }
        for (GLVolume *vol : vols) {
        	vol->bounding_box = vol->indexed_vertex_array.bounding_box();
        	vol->indexed_vertex_array.shrink_to_fit();
        }
    });

    BOOST_LOG_TRIVIAL(debug) << "Loading print object toolpaths in parallel - finalizing results";
    // Remove empty volumes from the newly added volumes.
    m_volumes.volumes.erase(
        std::remove_if(m_volumes.volumes.begin() + volumes_cnt_initial, m_volumes.volumes.end(),
        [](const GLVolume *volume) { return volume->empty(); }),
        m_volumes.volumes.end());
    for (size_t i = volumes_cnt_initial; i < m_volumes.volumes.size(); ++i)
        m_volumes.volumes[i]->indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);

    BOOST_LOG_TRIVIAL(debug) << "Loading print object toolpaths in parallel - end";
}

void GLCanvas3D::_load_wipe_tower_toolpaths(const std::vector<std::string>& str_tool_colors)
{
    const Print *print = this->fff_print();
    if ((print == nullptr) || print->wipe_tower_data().tool_changes.empty())
        return;

    if (!print->is_step_done(psWipeTower))
        return;

    std::vector<float> tool_colors = _parse_colors(str_tool_colors);

    struct Ctxt
    {
        const Print                 *print;
        const std::vector<float>    *tool_colors;
        WipeTower::xy                wipe_tower_pos;
        float                        wipe_tower_angle;

        // Number of vertices (each vertex is 6x4=24 bytes long)
        static const size_t          alloc_size_max() { return 131072; } // 3.15MB
        static const size_t          alloc_size_reserve() { return alloc_size_max() * 2; }

        static const float*          color_support() { static float color[4] = { 0.5f, 1.0f, 0.5f, 1.f }; return color; } // greenish

        // For cloring by a tool, return a parsed color.
        bool                         color_by_tool() const { return tool_colors != nullptr; }
        size_t                       number_tools()  const { return this->color_by_tool() ? tool_colors->size() / 4 : 0; }
        const float*                 color_tool(size_t tool) const { return tool_colors->data() + tool * 4; }
        int                          volume_idx(int tool, int feature) const
        {
            return this->color_by_tool() ? std::min<int>(this->number_tools() - 1, std::max<int>(tool, 0)) : feature;
        }

        const std::vector<WipeTower::ToolChangeResult>& tool_change(size_t idx) {
            const auto &tool_changes = print->wipe_tower_data().tool_changes;
            return priming.empty() ?
                ((idx == tool_changes.size()) ? final : tool_changes[idx]) :
                ((idx == 0) ? priming : (idx == tool_changes.size() + 1) ? final : tool_changes[idx - 1]);
        }
        std::vector<WipeTower::ToolChangeResult> priming;
        std::vector<WipeTower::ToolChangeResult> final;
    } ctxt;

    ctxt.print = print;
    ctxt.tool_colors = tool_colors.empty() ? nullptr : &tool_colors;
    if (print->wipe_tower_data().priming && print->config().single_extruder_multi_material_priming)
        ctxt.priming.emplace_back(*print->wipe_tower_data().priming.get());
    if (print->wipe_tower_data().final_purge)
        ctxt.final.emplace_back(*print->wipe_tower_data().final_purge.get());

    ctxt.wipe_tower_angle = ctxt.print->config().wipe_tower_rotation_angle.value/180.f * PI;
    ctxt.wipe_tower_pos = WipeTower::xy(ctxt.print->config().wipe_tower_x.value, ctxt.print->config().wipe_tower_y.value);

    BOOST_LOG_TRIVIAL(debug) << "Loading wipe tower toolpaths in parallel - start";

    //FIXME Improve the heuristics for a grain size.
    size_t          n_items = print->wipe_tower_data().tool_changes.size() + (ctxt.priming.empty() ? 0 : 1);
    size_t          grain_size = std::max(n_items / 128, size_t(1));
    tbb::spin_mutex new_volume_mutex;
    auto            new_volume = [this, &new_volume_mutex](const float *color) -> GLVolume* {
        auto *volume = new GLVolume(color);
        new_volume_mutex.lock();
        m_volumes.volumes.emplace_back(volume);
        new_volume_mutex.unlock();
        return volume;
    };
    const size_t   volumes_cnt_initial = m_volumes.volumes.size();
    std::vector<GLVolumeCollection> volumes_per_thread(n_items);
    tbb::parallel_for(
        tbb::blocked_range<size_t>(0, n_items, grain_size),
        [&ctxt, &new_volume](const tbb::blocked_range<size_t>& range) {
        // Bounding box of this slab of a wipe tower.
        GLVolumePtrs vols;
        if (ctxt.color_by_tool()) {
            for (size_t i = 0; i < ctxt.number_tools(); ++i)
                vols.emplace_back(new_volume(ctxt.color_tool(i)));
        }
        else
            vols = { new_volume(ctxt.color_support()) };
        for (GLVolume *volume : vols)
            volume->indexed_vertex_array.reserve(ctxt.alloc_size_reserve());
        for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++idx_layer) {
            const std::vector<WipeTower::ToolChangeResult> &layer = ctxt.tool_change(idx_layer);
            for (size_t i = 0; i < vols.size(); ++i) {
                GLVolume &vol = *vols[i];
                if (vol.print_zs.empty() || vol.print_zs.back() != layer.front().print_z) {
                    vol.print_zs.push_back(layer.front().print_z);
                    vol.offsets.push_back(vol.indexed_vertex_array.quad_indices.size());
                    vol.offsets.push_back(vol.indexed_vertex_array.triangle_indices.size());
                }
            }
            for (const WipeTower::ToolChangeResult &extrusions : layer) {
                for (size_t i = 1; i < extrusions.extrusions.size();) {
                    const WipeTower::Extrusion &e = extrusions.extrusions[i];
                    if (e.width == 0.) {
                        ++i;
                        continue;
                    }
                    size_t j = i + 1;
                    if (ctxt.color_by_tool())
                        for (; j < extrusions.extrusions.size() && extrusions.extrusions[j].tool == e.tool && extrusions.extrusions[j].width > 0.f; ++j);
                    else
                        for (; j < extrusions.extrusions.size() && extrusions.extrusions[j].width > 0.f; ++j);
                    size_t              n_lines = j - i;
                    Lines               lines;
                    std::vector<double> widths;
                    std::vector<double> heights;
                    lines.reserve(n_lines);
                    widths.reserve(n_lines);
                    heights.assign(n_lines, extrusions.layer_height);
                    WipeTower::Extrusion e_prev = extrusions.extrusions[i-1];

                    if (!extrusions.priming) { // wipe tower extrusions describe the wipe tower at the origin with no rotation
                        e_prev.pos.rotate(ctxt.wipe_tower_angle);
                        e_prev.pos.translate(ctxt.wipe_tower_pos);
                    }

                    for (; i < j; ++i) {
                        WipeTower::Extrusion e = extrusions.extrusions[i];
                        assert(e.width > 0.f);
                        if (!extrusions.priming) {
                            e.pos.rotate(ctxt.wipe_tower_angle);
                            e.pos.translate(ctxt.wipe_tower_pos);
                        }

                        lines.emplace_back(Point::new_scale(e_prev.pos.x, e_prev.pos.y), Point::new_scale(e.pos.x, e.pos.y));
                        widths.emplace_back(e.width);

                        e_prev = e;
                    }
                    _3DScene::thick_lines_to_verts(lines, widths, heights, lines.front().a == lines.back().b, extrusions.print_z,
                        *vols[ctxt.volume_idx(e.tool, 0)]);
                }
            }
        }
        for (size_t i = 0; i < vols.size(); ++i) {
            GLVolume &vol = *vols[i];
            if (vol.indexed_vertex_array.vertices_and_normals_interleaved.size() / 6 > ctxt.alloc_size_max()) {
                // Store the vertex arrays and restart their containers, 
                vols[i] = new_volume(vol.color);
                GLVolume &vol_new = *vols[i];
                // Assign the large pre-allocated buffers to the new GLVolume.
                vol_new.indexed_vertex_array = std::move(vol.indexed_vertex_array);
                // Copy the content back to the old GLVolume.
                vol.indexed_vertex_array = vol_new.indexed_vertex_array;
                // Finalize a bounding box of the old GLVolume.
                vol.bounding_box = vol.indexed_vertex_array.bounding_box();
                // Clear the buffers, but keep them pre-allocated.
                vol_new.indexed_vertex_array.clear();
                // Just make sure that clear did not clear the reserved memory.
                vol_new.indexed_vertex_array.reserve(ctxt.alloc_size_reserve());
            }
        }
        for (GLVolume *vol : vols) {
            vol->bounding_box = vol->indexed_vertex_array.bounding_box();
            vol->indexed_vertex_array.shrink_to_fit();
        }
    });

    BOOST_LOG_TRIVIAL(debug) << "Loading wipe tower toolpaths in parallel - finalizing results";
    // Remove empty volumes from the newly added volumes.
    m_volumes.volumes.erase(
        std::remove_if(m_volumes.volumes.begin() + volumes_cnt_initial, m_volumes.volumes.end(),
        [](const GLVolume *volume) { return volume->empty(); }),
        m_volumes.volumes.end());
    for (size_t i = volumes_cnt_initial; i < m_volumes.volumes.size(); ++i)
        m_volumes.volumes[i]->indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);

    BOOST_LOG_TRIVIAL(debug) << "Loading wipe tower toolpaths in parallel - end";
}

static inline int hex_digit_to_int(const char c)
{
    return
        (c >= '0' && c <= '9') ? int(c - '0') :
        (c >= 'A' && c <= 'F') ? int(c - 'A') + 10 :
        (c >= 'a' && c <= 'f') ? int(c - 'a') + 10 : -1;
}

void GLCanvas3D::_load_gcode_extrusion_paths(const GCodePreviewData& preview_data, const std::vector<float>& tool_colors)
{
    // helper functions to select data in dependence of the extrusion view type
    struct Helper
    {
        static float path_filter(GCodePreviewData::Extrusion::EViewType type, const ExtrusionPath& path)
        {
            switch (type)
            {
            case GCodePreviewData::Extrusion::FeatureType:
                return (float)path.role();
            case GCodePreviewData::Extrusion::Height:
                return path.height;
            case GCodePreviewData::Extrusion::Width:
                return path.width;
            case GCodePreviewData::Extrusion::Feedrate:
                return path.feedrate;
            case GCodePreviewData::Extrusion::VolumetricRate:
                return path.feedrate * (float)path.mm3_per_mm;
            case GCodePreviewData::Extrusion::Tool:
                return (float)path.extruder_id;
            case GCodePreviewData::Extrusion::ColorPrint:
                return (float)path.cp_color_id;
            default:
                return 0.0f;
            }

            return 0.0f;
        }

        static GCodePreviewData::Color path_color(const GCodePreviewData& data, const std::vector<float>& tool_colors, float value)
        {
            switch (data.extrusion.view_type)
            {
            case GCodePreviewData::Extrusion::FeatureType:
                return data.get_extrusion_role_color((ExtrusionRole)(int)value);
            case GCodePreviewData::Extrusion::Height:
                return data.get_height_color(value);
            case GCodePreviewData::Extrusion::Width:
                return data.get_width_color(value);
            case GCodePreviewData::Extrusion::Feedrate:
                return data.get_feedrate_color(value);
            case GCodePreviewData::Extrusion::VolumetricRate:
                return data.get_volumetric_rate_color(value);
            case GCodePreviewData::Extrusion::Tool:
            {
                GCodePreviewData::Color color;
                ::memcpy((void*)color.rgba, (const void*)(tool_colors.data() + (unsigned int)value * 4), 4 * sizeof(float));
                return color;
            }
            case GCodePreviewData::Extrusion::ColorPrint:
            {
                const size_t color_cnt = tool_colors.size() / 4;

                int val = int(value);
                while (val >= color_cnt)
                    val -= color_cnt;
                    
                GCodePreviewData::Color color;
                ::memcpy((void*)color.rgba, (const void*)(tool_colors.data() + val * 4), 4 * sizeof(float));

                return color;
            }
            default:
                return GCodePreviewData::Color::Dummy;
            }

            return GCodePreviewData::Color::Dummy;
        }
    };

    // Helper structure for filters
    struct Filter
    {
        float value;
        ExtrusionRole role;
        GLVolume* volume;

        Filter(float value, ExtrusionRole role)
            : value(value)
            , role(role)
            , volume(nullptr)
        {
        }

        bool operator == (const Filter& other) const
        {
            if (value != other.value)
                return false;

            if (role != other.role)
                return false;

            return true;
        }
    };

    typedef std::vector<Filter> FiltersList;
    size_t initial_volumes_count = m_volumes.volumes.size();

    // detects filters
    FiltersList filters;
    for (const GCodePreviewData::Extrusion::Layer& layer : preview_data.extrusion.layers)
    {
        for (const ExtrusionPath& path : layer.paths)
        {
            ExtrusionRole role = path.role();
            float path_filter = Helper::path_filter(preview_data.extrusion.view_type, path);
            if (std::find(filters.begin(), filters.end(), Filter(path_filter, role)) == filters.end())
                filters.emplace_back(path_filter, role);
        }
    }

    // nothing to render, return
    if (filters.empty())
        return;

    // creates a new volume for each filter
    for (Filter& filter : filters)
    {
        m_gcode_preview_volume_index.first_volumes.emplace_back(GCodePreviewVolumeIndex::Extrusion, (unsigned int)filter.role, (unsigned int)m_volumes.volumes.size());
        GLVolume* volume = new GLVolume(Helper::path_color(preview_data, tool_colors, filter.value).rgba);
        if (volume != nullptr)
        {
            filter.volume = volume;
            volume->is_extrusion_path = true;
            m_volumes.volumes.emplace_back(volume);
        }
        else
        {
            // an error occourred - restore to previous state and return
            m_gcode_preview_volume_index.first_volumes.pop_back();
            if (initial_volumes_count != m_volumes.volumes.size())
            {
                GLVolumePtrs::iterator begin = m_volumes.volumes.begin() + initial_volumes_count;
                GLVolumePtrs::iterator end = m_volumes.volumes.end();
                for (GLVolumePtrs::iterator it = begin; it < end; ++it)
                {
                    GLVolume* volume = *it;
                    delete volume;
                }
                m_volumes.volumes.erase(begin, end);
                return;
            }
        }
    }

    // populates volumes
    for (const GCodePreviewData::Extrusion::Layer& layer : preview_data.extrusion.layers)
    {
        for (const ExtrusionPath& path : layer.paths)
        {
            float path_filter = Helper::path_filter(preview_data.extrusion.view_type, path);
            FiltersList::iterator filter = std::find(filters.begin(), filters.end(), Filter(path_filter, path.role()));
            if (filter != filters.end())
            {
                filter->volume->print_zs.push_back(layer.z);
                filter->volume->offsets.push_back(filter->volume->indexed_vertex_array.quad_indices.size());
                filter->volume->offsets.push_back(filter->volume->indexed_vertex_array.triangle_indices.size());

                _3DScene::extrusionentity_to_verts(path, layer.z, *filter->volume);
            }
        }
    }

    // finalize volumes and sends geometry to gpu
    if (m_volumes.volumes.size() > initial_volumes_count)
    {
        for (size_t i = initial_volumes_count; i < m_volumes.volumes.size(); ++i)
        {
            GLVolume* volume = m_volumes.volumes[i];
            volume->bounding_box = volume->indexed_vertex_array.bounding_box();
            volume->indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);
        }
    }
}

void GLCanvas3D::_load_gcode_travel_paths(const GCodePreviewData& preview_data, const std::vector<float>& tool_colors)
{
    size_t initial_volumes_count = m_volumes.volumes.size();
    m_gcode_preview_volume_index.first_volumes.emplace_back(GCodePreviewVolumeIndex::Travel, 0, (unsigned int)initial_volumes_count);

    bool res = true;
    switch (preview_data.extrusion.view_type)
    {
    case GCodePreviewData::Extrusion::Feedrate:
    {
        res = _travel_paths_by_feedrate(preview_data);
        break;
    }
    case GCodePreviewData::Extrusion::Tool:
    {
        res = _travel_paths_by_tool(preview_data, tool_colors);
        break;
    }
    default:
    {
        res = _travel_paths_by_type(preview_data);
        break;
    }
    }

    if (!res)
    {
        // an error occourred - restore to previous state and return
        if (initial_volumes_count != m_volumes.volumes.size())
        {
            GLVolumePtrs::iterator begin = m_volumes.volumes.begin() + initial_volumes_count;
            GLVolumePtrs::iterator end = m_volumes.volumes.end();
            for (GLVolumePtrs::iterator it = begin; it < end; ++it)
            {
                GLVolume* volume = *it;
                delete volume;
            }
            m_volumes.volumes.erase(begin, end);
        }

        return;
    }

    // finalize volumes and sends geometry to gpu
    if (m_volumes.volumes.size() > initial_volumes_count)
    {
        for (size_t i = initial_volumes_count; i < m_volumes.volumes.size(); ++i)
        {
            GLVolume* volume = m_volumes.volumes[i];
            volume->bounding_box = volume->indexed_vertex_array.bounding_box();
            volume->indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);
        }
    }
}

bool GLCanvas3D::_travel_paths_by_type(const GCodePreviewData& preview_data)
{
    // Helper structure for types
    struct Type
    {
        GCodePreviewData::Travel::EType value;
        GLVolume* volume;

        explicit Type(GCodePreviewData::Travel::EType value)
            : value(value)
            , volume(nullptr)
        {
        }

        bool operator == (const Type& other) const
        {
            return value == other.value;
        }
    };

    typedef std::vector<Type> TypesList;

    // colors travels by travel type

    // detects types
    TypesList types;
    for (const GCodePreviewData::Travel::Polyline& polyline : preview_data.travel.polylines)
    {
        if (std::find(types.begin(), types.end(), Type(polyline.type)) == types.end())
            types.emplace_back(polyline.type);
    }

    // nothing to render, return
    if (types.empty())
        return true;

    // creates a new volume for each type
    for (Type& type : types)
    {
        GLVolume* volume = new GLVolume(preview_data.travel.type_colors[type.value].rgba);
        if (volume == nullptr)
            return false;
        else
        {
            type.volume = volume;
            m_volumes.volumes.emplace_back(volume);
        }
    }

    // populates volumes
    for (const GCodePreviewData::Travel::Polyline& polyline : preview_data.travel.polylines)
    {
        TypesList::iterator type = std::find(types.begin(), types.end(), Type(polyline.type));
        if (type != types.end())
        {
            type->volume->print_zs.push_back(unscale<double>(polyline.polyline.bounding_box().min(2)));
            type->volume->offsets.push_back(type->volume->indexed_vertex_array.quad_indices.size());
            type->volume->offsets.push_back(type->volume->indexed_vertex_array.triangle_indices.size());

            _3DScene::polyline3_to_verts(polyline.polyline, preview_data.travel.width, preview_data.travel.height, *type->volume);
        }
    }

    return true;
}

bool GLCanvas3D::_travel_paths_by_feedrate(const GCodePreviewData& preview_data)
{
    // Helper structure for feedrate
    struct Feedrate
    {
        float value;
        GLVolume* volume;

        explicit Feedrate(float value)
            : value(value)
            , volume(nullptr)
        {
        }

        bool operator == (const Feedrate& other) const
        {
            return value == other.value;
        }
    };

    typedef std::vector<Feedrate> FeedratesList;

    // colors travels by feedrate

    // detects feedrates
    FeedratesList feedrates;
    for (const GCodePreviewData::Travel::Polyline& polyline : preview_data.travel.polylines)
    {
        if (std::find(feedrates.begin(), feedrates.end(), Feedrate(polyline.feedrate)) == feedrates.end())
            feedrates.emplace_back(polyline.feedrate);
    }

    // nothing to render, return
    if (feedrates.empty())
        return true;

    // creates a new volume for each feedrate
    for (Feedrate& feedrate : feedrates)
    {
        GLVolume* volume = new GLVolume(preview_data.get_feedrate_color(feedrate.value).rgba);
        if (volume == nullptr)
            return false;
        else
        {
            feedrate.volume = volume;
            m_volumes.volumes.emplace_back(volume);
        }
    }

    // populates volumes
    for (const GCodePreviewData::Travel::Polyline& polyline : preview_data.travel.polylines)
    {
        FeedratesList::iterator feedrate = std::find(feedrates.begin(), feedrates.end(), Feedrate(polyline.feedrate));
        if (feedrate != feedrates.end())
        {
            feedrate->volume->print_zs.push_back(unscale<double>(polyline.polyline.bounding_box().min(2)));
            feedrate->volume->offsets.push_back(feedrate->volume->indexed_vertex_array.quad_indices.size());
            feedrate->volume->offsets.push_back(feedrate->volume->indexed_vertex_array.triangle_indices.size());

            _3DScene::polyline3_to_verts(polyline.polyline, preview_data.travel.width, preview_data.travel.height, *feedrate->volume);
        }
    }

    return true;
}

bool GLCanvas3D::_travel_paths_by_tool(const GCodePreviewData& preview_data, const std::vector<float>& tool_colors)
{
    // Helper structure for tool
    struct Tool
    {
        unsigned int value;
        GLVolume* volume;

        explicit Tool(unsigned int value)
            : value(value)
            , volume(nullptr)
        {
        }

        bool operator == (const Tool& other) const
        {
            return value == other.value;
        }
    };

    typedef std::vector<Tool> ToolsList;

    // colors travels by tool

    // detects tools
    ToolsList tools;
    for (const GCodePreviewData::Travel::Polyline& polyline : preview_data.travel.polylines)
    {
        if (std::find(tools.begin(), tools.end(), Tool(polyline.extruder_id)) == tools.end())
            tools.emplace_back(polyline.extruder_id);
    }

    // nothing to render, return
    if (tools.empty())
        return true;

    // creates a new volume for each tool
    for (Tool& tool : tools)
    {
        // tool.value could be invalid (as it was with https://github.com/prusa3d/PrusaSlicer/issues/2179), we better check
        if (tool.value >= tool_colors.size())
            continue;

        GLVolume* volume = new GLVolume(tool_colors.data() + tool.value * 4);
        if (volume == nullptr)
            return false;
        else
        {
            tool.volume = volume;
            m_volumes.volumes.emplace_back(volume);
        }
    }

    // populates volumes
    for (const GCodePreviewData::Travel::Polyline& polyline : preview_data.travel.polylines)
    {
        ToolsList::iterator tool = std::find(tools.begin(), tools.end(), Tool(polyline.extruder_id));
        if (tool != tools.end() && tool->volume != nullptr)
        {
            tool->volume->print_zs.push_back(unscale<double>(polyline.polyline.bounding_box().min(2)));
            tool->volume->offsets.push_back(tool->volume->indexed_vertex_array.quad_indices.size());
            tool->volume->offsets.push_back(tool->volume->indexed_vertex_array.triangle_indices.size());

            _3DScene::polyline3_to_verts(polyline.polyline, preview_data.travel.width, preview_data.travel.height, *tool->volume);
        }
    }

    return true;
}

void GLCanvas3D::_load_gcode_retractions(const GCodePreviewData& preview_data)
{
    m_gcode_preview_volume_index.first_volumes.emplace_back(GCodePreviewVolumeIndex::Retraction, 0, (unsigned int)m_volumes.volumes.size());

    // nothing to render, return
    if (preview_data.retraction.positions.empty())
        return;

    GLVolume* volume = new GLVolume(preview_data.retraction.color.rgba);
    if (volume != nullptr)
    {
        m_volumes.volumes.emplace_back(volume);

        GCodePreviewData::Retraction::PositionsList copy(preview_data.retraction.positions);
        std::sort(copy.begin(), copy.end(), [](const GCodePreviewData::Retraction::Position& p1, const GCodePreviewData::Retraction::Position& p2){ return p1.position(2) < p2.position(2); });

        for (const GCodePreviewData::Retraction::Position& position : copy)
        {
            volume->print_zs.push_back(unscale<double>(position.position(2)));
            volume->offsets.push_back(volume->indexed_vertex_array.quad_indices.size());
            volume->offsets.push_back(volume->indexed_vertex_array.triangle_indices.size());

            _3DScene::point3_to_verts(position.position, position.width, position.height, *volume);
        }

        // finalize volumes and sends geometry to gpu
        volume->bounding_box = volume->indexed_vertex_array.bounding_box();
        volume->indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);
    }
}

void GLCanvas3D::_load_gcode_unretractions(const GCodePreviewData& preview_data)
{
    m_gcode_preview_volume_index.first_volumes.emplace_back(GCodePreviewVolumeIndex::Unretraction, 0, (unsigned int)m_volumes.volumes.size());

    // nothing to render, return
    if (preview_data.unretraction.positions.empty())
        return;

    GLVolume* volume = new GLVolume(preview_data.unretraction.color.rgba);
    if (volume != nullptr)
    {
        m_volumes.volumes.emplace_back(volume);

        GCodePreviewData::Retraction::PositionsList copy(preview_data.unretraction.positions);
        std::sort(copy.begin(), copy.end(), [](const GCodePreviewData::Retraction::Position& p1, const GCodePreviewData::Retraction::Position& p2){ return p1.position(2) < p2.position(2); });

        for (const GCodePreviewData::Retraction::Position& position : copy)
        {
            volume->print_zs.push_back(unscale<double>(position.position(2)));
            volume->offsets.push_back(volume->indexed_vertex_array.quad_indices.size());
            volume->offsets.push_back(volume->indexed_vertex_array.triangle_indices.size());

            _3DScene::point3_to_verts(position.position, position.width, position.height, *volume);
        }

        // finalize volumes and sends geometry to gpu
        volume->bounding_box = volume->indexed_vertex_array.bounding_box();
        volume->indexed_vertex_array.finalize_geometry(m_use_VBOs && m_initialized);
    }
}

void GLCanvas3D::_load_fff_shells()
{
    size_t initial_volumes_count = m_volumes.volumes.size();
    m_gcode_preview_volume_index.first_volumes.emplace_back(GCodePreviewVolumeIndex::Shell, 0, (unsigned int)initial_volumes_count);

    const Print *print = this->fff_print();
    if (print->objects().empty())
        // nothing to render, return
        return;

    // adds objects' volumes 
    int object_id = 0;
    for (const PrintObject* obj : print->objects())
    {
        const ModelObject* model_obj = obj->model_object();

        std::vector<int> instance_ids(model_obj->instances.size());
        for (int i = 0; i < (int)model_obj->instances.size(); ++i)
        {
            instance_ids[i] = i;
        }

        m_volumes.load_object(model_obj, object_id, instance_ids, "object", m_use_VBOs && m_initialized);

        ++object_id;
    }

    if (wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() == ptFFF) {
        // adds wipe tower's volume
        double max_z = print->objects()[0]->model_object()->get_model()->bounding_box().max(2);
        const PrintConfig& config = print->config();
        unsigned int extruders_count = config.nozzle_diameter.size();
        if ((extruders_count > 1) && config.single_extruder_multi_material && config.wipe_tower && !config.complete_objects) {
            float depth = print->get_wipe_tower_depth();

            // Calculate wipe tower brim spacing.
            const DynamicPrintConfig &print_config  = wxGetApp().preset_bundle->prints.get_edited_preset().config;
            double layer_height                     = print_config.opt_float("layer_height");
            double first_layer_height               = print_config.get_abs_value("first_layer_height", layer_height);
            float brim_spacing = print->config().nozzle_diameter.values[0] * 1.25f - first_layer_height * (1. - M_PI_4);

            if (!print->is_step_done(psWipeTower))
                depth = (900.f/config.wipe_tower_width) * (float)(extruders_count - 1) ;
            m_volumes.load_wipe_tower_preview(1000, config.wipe_tower_x, config.wipe_tower_y, config.wipe_tower_width, depth, max_z, config.wipe_tower_rotation_angle,
                                              m_use_VBOs && m_initialized, !print->is_step_done(psWipeTower), brim_spacing * 4.5f);
        }
    }
}

void GLCanvas3D::_load_sla_shells()
{
    //FIXME use reload_scene
#if 1
    const SLAPrint* print = this->sla_print();
    if (print->objects().empty())
        // nothing to render, return
        return;

    auto add_volume = [this](const SLAPrintObject &object, int volume_id, const SLAPrintObject::Instance& instance,
        const TriangleMesh &mesh, const float color[4], bool outside_printer_detection_enabled) {
        m_volumes.volumes.emplace_back(new GLVolume(color));
        GLVolume& v = *m_volumes.volumes.back();
        v.indexed_vertex_array.load_mesh(mesh, m_use_VBOs);
		v.shader_outside_printer_detection_enabled = outside_printer_detection_enabled;
        v.composite_id.volume_id = volume_id;
        v.set_instance_offset(unscale(instance.shift(0), instance.shift(1), 0));
        v.set_instance_rotation(Vec3d(0.0, 0.0, (double)instance.rotation));
        v.set_instance_mirror(X, object.is_left_handed() ? -1. : 1.);
        v.set_convex_hull(mesh.convex_hull_3d());
    };

    // adds objects' volumes 
    for (const SLAPrintObject* obj : print->objects())
        if (obj->is_step_done(slaposSliceSupports)) {
            unsigned int initial_volumes_count = (unsigned int)m_volumes.volumes.size();
            for (const SLAPrintObject::Instance& instance : obj->instances()) {
                add_volume(*obj, 0, instance, obj->transformed_mesh(), GLVolume::MODEL_COLOR[0], true);
                // Set the extruder_id and volume_id to achieve the same color as in the 3D scene when
                // through the update_volumes_colors_by_extruder() call.
                m_volumes.volumes.back()->extruder_id = obj->model_object()->volumes.front()->extruder_id();
                if (obj->is_step_done(slaposSupportTree) && obj->has_mesh(slaposSupportTree))
                    add_volume(*obj, -int(slaposSupportTree), instance, obj->support_mesh(), GLVolume::SLA_SUPPORT_COLOR, true);
                if (obj->is_step_done(slaposBasePool) && obj->has_mesh(slaposBasePool))
                    add_volume(*obj, -int(slaposBasePool), instance, obj->pad_mesh(), GLVolume::SLA_PAD_COLOR, false);
            }
            double shift_z = obj->get_current_elevation();
            for (unsigned int i = initial_volumes_count; i < m_volumes.volumes.size(); ++ i) {
                GLVolume& v = *m_volumes.volumes[i];
                // finalize volumes and sends geometry to gpu
                v.bounding_box = v.indexed_vertex_array.bounding_box();
                v.indexed_vertex_array.finalize_geometry(m_use_VBOs);
                // apply shift z
                v.set_sla_shift_z(shift_z);
            }
        }

    update_volumes_colors_by_extruder();
#else
    this->reload_scene(true, true);
#endif
}

void GLCanvas3D::_update_gcode_volumes_visibility(const GCodePreviewData& preview_data)
{
    unsigned int size = (unsigned int)m_gcode_preview_volume_index.first_volumes.size();
    for (unsigned int i = 0; i < size; ++i)
    {
        GLVolumePtrs::iterator begin = m_volumes.volumes.begin() + m_gcode_preview_volume_index.first_volumes[i].id;
        GLVolumePtrs::iterator end = (i + 1 < size) ? m_volumes.volumes.begin() + m_gcode_preview_volume_index.first_volumes[i + 1].id : m_volumes.volumes.end();

        for (GLVolumePtrs::iterator it = begin; it != end; ++it)
        {
            GLVolume* volume = *it;

            switch (m_gcode_preview_volume_index.first_volumes[i].type)
            {
            case GCodePreviewVolumeIndex::Extrusion:
            {
                if ((ExtrusionRole)m_gcode_preview_volume_index.first_volumes[i].flag == erCustom)
                    volume->zoom_to_volumes = false;

                volume->is_active = preview_data.extrusion.is_role_flag_set((ExtrusionRole)m_gcode_preview_volume_index.first_volumes[i].flag);
                break;
            }
            case GCodePreviewVolumeIndex::Travel:
            {
                volume->is_active = preview_data.travel.is_visible;
                volume->zoom_to_volumes = false;
                break;
            }
            case GCodePreviewVolumeIndex::Retraction:
            {
                volume->is_active = preview_data.retraction.is_visible;
                volume->zoom_to_volumes = false;
                break;
            }
            case GCodePreviewVolumeIndex::Unretraction:
            {
                volume->is_active = preview_data.unretraction.is_visible;
                volume->zoom_to_volumes = false;
                break;
            }
            case GCodePreviewVolumeIndex::Shell:
            {
                volume->is_active = preview_data.shell.is_visible;
                volume->color[3] = 0.25f;
                volume->zoom_to_volumes = false;
                break;
            }
            default:
            {
                volume->is_active = false;
                volume->zoom_to_volumes = false;
                break;
            }
            }
        }
    }
}

void GLCanvas3D::_update_toolpath_volumes_outside_state()
{
    // tolerance to avoid false detection at bed edges
    static const double tolerance_x = 0.05;
    static const double tolerance_y = 0.05;

    BoundingBoxf3 print_volume;
    if (m_config != nullptr)
    {
        const ConfigOptionPoints* opt = dynamic_cast<const ConfigOptionPoints*>(m_config->option("bed_shape"));
        if (opt != nullptr)
        {
            BoundingBox bed_box_2D = get_extents(Polygon::new_scale(opt->values));
            print_volume = BoundingBoxf3(Vec3d(unscale<double>(bed_box_2D.min(0)) - tolerance_x, unscale<double>(bed_box_2D.min(1)) - tolerance_y, 0.0), Vec3d(unscale<double>(bed_box_2D.max(0)) + tolerance_x, unscale<double>(bed_box_2D.max(1)) + tolerance_y, m_config->opt_float("max_print_height")));
            // Allow the objects to protrude below the print bed
            print_volume.min(2) = -1e10;
        }
    }

    for (GLVolume* volume : m_volumes.volumes)
    {
        volume->is_outside = ((print_volume.radius() > 0.0) && volume->is_extrusion_path) ? !print_volume.contains(volume->bounding_box) : false;
    }
}

void GLCanvas3D::_update_sla_shells_outside_state()
{
    // tolerance to avoid false detection at bed edges
    static const double tolerance_x = 0.05;
    static const double tolerance_y = 0.05;

    BoundingBoxf3 print_volume;
    if (m_config != nullptr)
    {
        const ConfigOptionPoints* opt = dynamic_cast<const ConfigOptionPoints*>(m_config->option("bed_shape"));
        if (opt != nullptr)
        {
            BoundingBox bed_box_2D = get_extents(Polygon::new_scale(opt->values));
            print_volume = BoundingBoxf3(Vec3d(unscale<double>(bed_box_2D.min(0)) - tolerance_x, unscale<double>(bed_box_2D.min(1)) - tolerance_y, 0.0), Vec3d(unscale<double>(bed_box_2D.max(0)) + tolerance_x, unscale<double>(bed_box_2D.max(1)) + tolerance_y, m_config->opt_float("max_print_height")));
            // Allow the objects to protrude below the print bed
            print_volume.min(2) = -1e10;
        }
    }

    for (GLVolume* volume : m_volumes.volumes)
    {
        volume->is_outside = ((print_volume.radius() > 0.0) && volume->shader_outside_printer_detection_enabled) ? !print_volume.contains(volume->transformed_convex_hull_bounding_box()) : false;
    }
}

void GLCanvas3D::_show_warning_texture_if_needed(WarningTexture::Warning warning)
{
    _set_current();
    _set_warning_texture(warning, _is_any_volume_outside());
}

std::vector<float> GLCanvas3D::_parse_colors(const std::vector<std::string>& colors)
{
    static const float INV_255 = 1.0f / 255.0f;

    std::vector<float> output(colors.size() * 4, 1.0f);
    for (size_t i = 0; i < colors.size(); ++i)
    {
        const std::string& color = colors[i];
        const char* c = color.data() + 1;
        if ((color.size() == 7) && (color.front() == '#'))
        {
            for (size_t j = 0; j < 3; ++j)
            {
                int digit1 = hex_digit_to_int(*c++);
                int digit2 = hex_digit_to_int(*c++);
                if ((digit1 == -1) || (digit2 == -1))
                    break;

                output[i * 4 + j] = float(digit1 * 16 + digit2) * INV_255;
            }
        }
    }
    return output;
}

void GLCanvas3D::_generate_legend_texture(const GCodePreviewData& preview_data, const std::vector<float>& tool_colors)
{
    m_legend_texture.generate(preview_data, tool_colors, *this, true);
}

void GLCanvas3D::_set_warning_texture(WarningTexture::Warning warning, bool state)
{
    m_warning_texture.activate(warning, state, *this);
}

bool GLCanvas3D::_is_any_volume_outside() const
{
    for (const GLVolume* volume : m_volumes.volumes)
    {
        if ((volume != nullptr) && volume->is_outside)
            return true;
    }

    return false;
}

#if !ENABLE_SVG_ICONS
void GLCanvas3D::_resize_toolbars() const
{
    Size cnv_size = get_canvas_size();
    float zoom = get_camera_zoom();
    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;

#if ENABLE_RETINA_GL
    m_toolbar.set_icons_scale(m_retina_helper->get_scale_factor());
#else
    m_toolbar.set_icons_scale(m_canvas->GetContentScaleFactor());
#endif /* __WXMSW__ */

    GLToolbar::Layout::EOrientation orientation = m_toolbar.get_layout_orientation();

    switch (m_toolbar.get_layout_type())
    {
    default:
    case GLToolbar::Layout::Horizontal:
    {
        // centers the toolbar on the top edge of the 3d scene
        float top, left;
        if (orientation == GLToolbar::Layout::Top)
        {
            top = 0.5f * (float)cnv_size.get_height() * inv_zoom;
            left = -0.5f * m_toolbar.get_width() * inv_zoom;
        }
        else
        {
            top = (-0.5f * (float)cnv_size.get_height() + m_view_toolbar.get_height()) * inv_zoom;
            left = -0.5f * m_toolbar.get_width() * inv_zoom;
        }
        m_toolbar.set_position(top, left);
        break;
    }
    case GLToolbar::Layout::Vertical:
    {
        // centers the toolbar on the right edge of the 3d scene
        float top, left;
        if (orientation == GLToolbar::Layout::Left)
        {
            top = 0.5f * m_toolbar.get_height() * inv_zoom;
            left = (-0.5f * (float)cnv_size.get_width()) * inv_zoom;
        }
        else
        {
            top = 0.5f * m_toolbar.get_height() * inv_zoom;
            left = (0.5f * (float)cnv_size.get_width() - m_toolbar.get_width()) * inv_zoom;
        }
        m_toolbar.set_position(top, left);
        break;
    }
    }

    if (m_view_toolbar != nullptr)
    {
#if ENABLE_RETINA_GL
        m_view_toolbar.set_icons_scale(m_retina_helper->get_scale_factor());
#else
        m_view_toolbar.set_icons_scale(m_canvas->GetContentScaleFactor());
#endif /* __WXMSW__ */

        // places the toolbar on the bottom-left corner of the 3d scene
        float top = (-0.5f * (float)cnv_size.get_height() + m_view_toolbar.get_height()) * inv_zoom;
        float left = -0.5f * (float)cnv_size.get_width() * inv_zoom;
        m_view_toolbar.set_position(top, left);
    }
}
#endif // !ENABLE_SVG_ICONS

void GLCanvas3D::_update_selection_from_hover()
{
    bool ctrl_pressed = wxGetKeyState(WXK_CONTROL);

    if (m_hover_volume_idxs.empty())
    {
        if (!ctrl_pressed && (m_rectangle_selection.get_state() == GLSelectionRectangle::Select))
            m_selection.clear();

        return;
    }

    GLSelectionRectangle::EState state = m_rectangle_selection.get_state();

    bool hover_modifiers_only = true;
    for (int i : m_hover_volume_idxs)
    {
        if (!m_volumes.volumes[i]->is_modifier)
        {
            hover_modifiers_only = false;
            break;
        }
    }

    if ((state == GLSelectionRectangle::Select) && !ctrl_pressed)
        m_selection.clear();

    for (int i : m_hover_volume_idxs)
    {
        if (state == GLSelectionRectangle::Select)
        {
            if (hover_modifiers_only)
            {
                const GLVolume& v = *m_volumes.volumes[i];
                m_selection.add_volume(v.object_idx(), v.volume_idx(), v.instance_idx(), false);
            }
            else
                m_selection.add(i, false);
        }
        else
            m_selection.remove(i);
    }

    if (m_selection.is_empty())
        m_gizmos.reset_all_states();
    else
        m_gizmos.refresh_on_off_state(m_selection);

    m_gizmos.update_data(*this);
    post_event(SimpleEvent(EVT_GLCANVAS_OBJECT_SELECT));
    m_dirty = true;
}

bool GLCanvas3D::_deactivate_undo_redo_toolbar_items()
{
    if (m_toolbar.is_item_pressed("undo"))
    {
        m_toolbar.force_right_action(m_toolbar.get_item_id("undo"), *this);
        return true;
    }
    else if (m_toolbar.is_item_pressed("redo"))
    {
        m_toolbar.force_right_action(m_toolbar.get_item_id("redo"), *this);
        return true;
    }

    return false;
}

const Print* GLCanvas3D::fff_print() const
{
    return (m_process == nullptr) ? nullptr : m_process->fff_print();
}

const SLAPrint* GLCanvas3D::sla_print() const
{
    return (m_process == nullptr) ? nullptr : m_process->sla_print();
}

} // namespace GUI
} // namespace Slic3r