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/* SPDX-License-Identifier: GPL-2.0-or-later */
#include <algorithm>
#include "curves_sculpt_intern.hh"
#include "BLI_float4x4.hh"
#include "BLI_index_mask_ops.hh"
#include "BLI_kdtree.h"
#include "BLI_rand.hh"
#include "BLI_vector.hh"
#include "PIL_time.h"
#include "DEG_depsgraph.h"
#include "BKE_attribute_math.hh"
#include "BKE_brush.h"
#include "BKE_bvhutils.h"
#include "BKE_context.h"
#include "BKE_curves.hh"
#include "BKE_mesh.h"
#include "BKE_mesh_runtime.h"
#include "BKE_paint.h"
#include "DNA_brush_enums.h"
#include "DNA_brush_types.h"
#include "DNA_curves_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"
#include "ED_screen.h"
#include "ED_view3d.h"
#include "UI_interface.h"
#include "WM_api.h"
/**
* The code below uses a prefix naming convention to indicate the coordinate space:
* cu: Local space of the curves object that is being edited.
* su: Local space of the surface object.
* wo: World space.
* re: 2D coordinates within the region.
*/
namespace blender::ed::sculpt_paint {
using blender::bke::CurvesGeometry;
using threading::EnumerableThreadSpecific;
/**
* Moves individual points under the brush and does a length preservation step afterwards.
*/
class CombOperation : public CurvesSculptStrokeOperation {
private:
/** Last mouse position. */
float2 brush_pos_last_re_;
/** Only used when a 3D brush is used. */
CurvesBrush3D brush_3d_;
/** Length of each segment indexed by the index of the first point in the segment. */
Array<float> segment_lengths_cu_;
friend struct CombOperationExecutor;
public:
void on_stroke_extended(const bContext &C, const StrokeExtension &stroke_extension) override;
};
/**
* Utility class that actually executes the update when the stroke is updated. That's useful
* because it avoids passing a very large number of parameters between functions.
*/
struct CombOperationExecutor {
CombOperation *self_ = nullptr;
const Depsgraph *depsgraph_ = nullptr;
const Scene *scene_ = nullptr;
ARegion *region_ = nullptr;
const View3D *v3d_ = nullptr;
const RegionView3D *rv3d_ = nullptr;
const CurvesSculpt *curves_sculpt_ = nullptr;
const Brush *brush_ = nullptr;
float brush_radius_re_;
float brush_strength_;
eBrushFalloffShape falloff_shape_;
Object *object_ = nullptr;
Curves *curves_id_ = nullptr;
CurvesGeometry *curves_ = nullptr;
const Object *surface_ob_ = nullptr;
const Mesh *surface_ = nullptr;
Span<MLoopTri> surface_looptris_;
float2 brush_pos_prev_re_;
float2 brush_pos_re_;
float2 brush_pos_diff_re_;
float brush_pos_diff_length_re_;
float4x4 curves_to_world_mat_;
float4x4 world_to_curves_mat_;
float4x4 surface_to_world_mat_;
float4x4 world_to_surface_mat_;
BVHTreeFromMesh surface_bvh_;
void execute(CombOperation &self, const bContext &C, const StrokeExtension &stroke_extension)
{
self_ = &self;
BLI_SCOPED_DEFER([&]() { self_->brush_pos_last_re_ = stroke_extension.mouse_position; });
depsgraph_ = CTX_data_depsgraph_pointer(&C);
scene_ = CTX_data_scene(&C);
object_ = CTX_data_active_object(&C);
region_ = CTX_wm_region(&C);
v3d_ = CTX_wm_view3d(&C);
rv3d_ = CTX_wm_region_view3d(&C);
curves_sculpt_ = scene_->toolsettings->curves_sculpt;
brush_ = BKE_paint_brush_for_read(&curves_sculpt_->paint);
brush_radius_re_ = BKE_brush_size_get(scene_, brush_);
brush_strength_ = BKE_brush_alpha_get(scene_, brush_);
curves_to_world_mat_ = object_->obmat;
world_to_curves_mat_ = curves_to_world_mat_.inverted();
falloff_shape_ = static_cast<eBrushFalloffShape>(brush_->falloff_shape);
curves_id_ = static_cast<Curves *>(object_->data);
curves_ = &CurvesGeometry::wrap(curves_id_->geometry);
if (curves_->curves_num() == 0) {
return;
}
brush_pos_prev_re_ = self_->brush_pos_last_re_;
brush_pos_re_ = stroke_extension.mouse_position;
brush_pos_diff_re_ = brush_pos_re_ - brush_pos_prev_re_;
brush_pos_diff_length_re_ = math::length(brush_pos_diff_re_);
surface_ob_ = curves_id_->surface;
if (surface_ob_ != nullptr) {
surface_ = static_cast<const Mesh *>(surface_ob_->data);
surface_looptris_ = {BKE_mesh_runtime_looptri_ensure(surface_),
BKE_mesh_runtime_looptri_len(surface_)};
surface_to_world_mat_ = surface_ob_->obmat;
world_to_surface_mat_ = surface_to_world_mat_.inverted();
BKE_bvhtree_from_mesh_get(&surface_bvh_, surface_, BVHTREE_FROM_LOOPTRI, 2);
}
BLI_SCOPED_DEFER([&]() {
if (surface_ob_ != nullptr) {
free_bvhtree_from_mesh(&surface_bvh_);
}
});
if (stroke_extension.is_first) {
if (falloff_shape_ == PAINT_FALLOFF_SHAPE_SPHERE) {
this->initialize_spherical_brush_reference_point();
}
this->initialize_segment_lengths();
/* Combing does nothing when there is no mouse movement, so return directly. */
return;
}
EnumerableThreadSpecific<Vector<int>> changed_curves;
if (falloff_shape_ == PAINT_FALLOFF_SHAPE_TUBE) {
this->comb_projected_with_symmetry(changed_curves);
}
else if (falloff_shape_ == PAINT_FALLOFF_SHAPE_SPHERE) {
this->comb_spherical_with_symmetry(changed_curves);
}
else {
BLI_assert_unreachable();
}
this->restore_segment_lengths(changed_curves);
curves_->tag_positions_changed();
DEG_id_tag_update(&curves_id_->id, ID_RECALC_GEOMETRY);
WM_main_add_notifier(NC_GEOM | ND_DATA, &curves_id_->id);
ED_region_tag_redraw(region_);
}
/**
* Do combing in screen space.
*/
void comb_projected_with_symmetry(EnumerableThreadSpecific<Vector<int>> &r_changed_curves)
{
const Vector<float4x4> symmetry_brush_transforms = get_symmetry_brush_transforms(
eCurvesSymmetryType(curves_id_->symmetry));
for (const float4x4 &brush_transform : symmetry_brush_transforms) {
this->comb_projected(r_changed_curves, brush_transform);
}
}
void comb_projected(EnumerableThreadSpecific<Vector<int>> &r_changed_curves,
const float4x4 &brush_transform)
{
const float4x4 brush_transform_inv = brush_transform.inverted();
MutableSpan<float3> positions_cu = curves_->positions_for_write();
float4x4 projection;
ED_view3d_ob_project_mat_get(rv3d_, object_, projection.values);
const float brush_radius_sq_re = pow2f(brush_radius_re_);
threading::parallel_for(curves_->curves_range(), 256, [&](const IndexRange curves_range) {
Vector<int> &local_changed_curves = r_changed_curves.local();
for (const int curve_i : curves_range) {
bool curve_changed = false;
const IndexRange points = curves_->points_for_curve(curve_i);
for (const int point_i : points.drop_front(1)) {
const float3 old_pos_cu = brush_transform_inv * positions_cu[point_i];
/* Find the position of the point in screen space. */
float2 old_pos_re;
ED_view3d_project_float_v2_m4(region_, old_pos_cu, old_pos_re, projection.values);
const float distance_to_brush_sq_re = dist_squared_to_line_segment_v2(
old_pos_re, brush_pos_prev_re_, brush_pos_re_);
if (distance_to_brush_sq_re > brush_radius_sq_re) {
/* Ignore the point because it's too far away. */
continue;
}
const float distance_to_brush_re = std::sqrt(distance_to_brush_sq_re);
/* A falloff that is based on how far away the point is from the stroke. */
const float radius_falloff = BKE_brush_curve_strength(
brush_, distance_to_brush_re, brush_radius_re_);
/* Combine the falloff and brush strength. */
const float weight = brush_strength_ * radius_falloff;
/* Offset the old point position in screen space and transform it back into 3D space. */
const float2 new_position_re = old_pos_re + brush_pos_diff_re_ * weight;
float3 new_position_wo;
ED_view3d_win_to_3d(
v3d_, region_, curves_to_world_mat_ * old_pos_cu, new_position_re, new_position_wo);
const float3 new_position_cu = brush_transform *
(world_to_curves_mat_ * new_position_wo);
positions_cu[point_i] = new_position_cu;
curve_changed = true;
}
if (curve_changed) {
local_changed_curves.append(curve_i);
}
}
});
}
/**
* Do combing in 3D space.
*/
void comb_spherical_with_symmetry(EnumerableThreadSpecific<Vector<int>> &r_changed_curves)
{
float4x4 projection;
ED_view3d_ob_project_mat_get(rv3d_, object_, projection.values);
float3 brush_start_wo, brush_end_wo;
ED_view3d_win_to_3d(v3d_,
region_,
curves_to_world_mat_ * self_->brush_3d_.position_cu,
brush_pos_prev_re_,
brush_start_wo);
ED_view3d_win_to_3d(v3d_,
region_,
curves_to_world_mat_ * self_->brush_3d_.position_cu,
brush_pos_re_,
brush_end_wo);
const float3 brush_start_cu = world_to_curves_mat_ * brush_start_wo;
const float3 brush_end_cu = world_to_curves_mat_ * brush_end_wo;
const float brush_radius_cu = self_->brush_3d_.radius_cu;
const Vector<float4x4> symmetry_brush_transforms = get_symmetry_brush_transforms(
eCurvesSymmetryType(curves_id_->symmetry));
for (const float4x4 &brush_transform : symmetry_brush_transforms) {
this->comb_spherical(r_changed_curves,
brush_transform * brush_start_cu,
brush_transform * brush_end_cu,
brush_radius_cu);
}
}
void comb_spherical(EnumerableThreadSpecific<Vector<int>> &r_changed_curves,
const float3 &brush_start_cu,
const float3 &brush_end_cu,
const float brush_radius_cu)
{
MutableSpan<float3> positions_cu = curves_->positions_for_write();
const float brush_radius_sq_cu = pow2f(brush_radius_cu);
const float3 brush_diff_cu = brush_end_cu - brush_start_cu;
threading::parallel_for(curves_->curves_range(), 256, [&](const IndexRange curves_range) {
Vector<int> &local_changed_curves = r_changed_curves.local();
for (const int curve_i : curves_range) {
bool curve_changed = false;
const IndexRange points = curves_->points_for_curve(curve_i);
for (const int point_i : points.drop_front(1)) {
const float3 pos_old_cu = positions_cu[point_i];
/* Compute distance to the brush. */
const float distance_to_brush_sq_cu = dist_squared_to_line_segment_v3(
pos_old_cu, brush_start_cu, brush_end_cu);
if (distance_to_brush_sq_cu > brush_radius_sq_cu) {
/* Ignore the point because it's too far away. */
continue;
}
const float distance_to_brush_cu = std::sqrt(distance_to_brush_sq_cu);
/* A falloff that is based on how far away the point is from the stroke. */
const float radius_falloff = BKE_brush_curve_strength(
brush_, distance_to_brush_cu, brush_radius_cu);
/* Combine the falloff and brush strength. */
const float weight = brush_strength_ * radius_falloff;
/* Update the point position. */
positions_cu[point_i] = pos_old_cu + weight * brush_diff_cu;
curve_changed = true;
}
if (curve_changed) {
local_changed_curves.append(curve_i);
}
}
});
}
/**
* Sample depth under mouse by looking at curves and the surface.
*/
void initialize_spherical_brush_reference_point()
{
std::optional<CurvesBrush3D> brush_3d = sample_curves_3d_brush(
*depsgraph_, *region_, *v3d_, *rv3d_, *object_, brush_pos_re_, brush_radius_re_);
if (brush_3d.has_value()) {
self_->brush_3d_ = *brush_3d;
}
}
/**
* Remember the initial length of all curve segments. This allows restoring the length after
* combing.
*/
void initialize_segment_lengths()
{
const Span<float3> positions_cu = curves_->positions();
self_->segment_lengths_cu_.reinitialize(curves_->points_num());
threading::parallel_for(curves_->curves_range(), 128, [&](const IndexRange range) {
for (const int curve_i : range) {
const IndexRange points = curves_->points_for_curve(curve_i);
for (const int point_i : points.drop_back(1)) {
const float3 &p1_cu = positions_cu[point_i];
const float3 &p2_cu = positions_cu[point_i + 1];
const float length_cu = math::distance(p1_cu, p2_cu);
self_->segment_lengths_cu_[point_i] = length_cu;
}
}
});
}
/**
* Restore previously stored length for each segment in the changed curves.
*/
void restore_segment_lengths(EnumerableThreadSpecific<Vector<int>> &changed_curves)
{
const Span<float> expected_lengths_cu = self_->segment_lengths_cu_;
MutableSpan<float3> positions_cu = curves_->positions_for_write();
threading::parallel_for_each(changed_curves, [&](const Vector<int> &changed_curves) {
threading::parallel_for(changed_curves.index_range(), 256, [&](const IndexRange range) {
for (const int curve_i : changed_curves.as_span().slice(range)) {
const IndexRange points = curves_->points_for_curve(curve_i);
for (const int segment_i : IndexRange(points.size() - 1)) {
const float3 &p1_cu = positions_cu[points[segment_i]];
float3 &p2_cu = positions_cu[points[segment_i] + 1];
const float3 direction = math::normalize(p2_cu - p1_cu);
const float expected_length_cu = expected_lengths_cu[points[segment_i]];
p2_cu = p1_cu + direction * expected_length_cu;
}
}
});
});
}
};
void CombOperation::on_stroke_extended(const bContext &C, const StrokeExtension &stroke_extension)
{
CombOperationExecutor executor;
executor.execute(*this, C, stroke_extension);
}
std::unique_ptr<CurvesSculptStrokeOperation> new_comb_operation()
{
return std::make_unique<CombOperation>();
}
} // namespace blender::ed::sculpt_paint
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