/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2008 Blender Foundation.
 * All rights reserved.
 *
 *
 * Contributor(s): Blender Foundation
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/editors/space_view3d/view3d_draw.c
 *  \ingroup spview3d
 */

#include <math.h>

#include "BLI_listbase.h"
#include "BLI_math.h"
#include "BLI_rect.h"
#include "BLI_string.h"
#include "BLI_threads.h"
#include "BLI_jitter_2d.h"

#include "BIF_gl.h"
#include "BIF_glutil.h"

#include "BKE_camera.h"
#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_key.h"
#include "BKE_main.h"
#include "BKE_scene.h"
#include "BKE_object.h"
#include "BKE_paint.h"
#include "BKE_unit.h"

#include "BLF_api.h"

#include "BLT_translation.h"

#include "DNA_armature_types.h"
#include "DNA_brush_types.h"
#include "DNA_camera_types.h"
#include "DNA_key_types.h"
#include "DNA_mesh_types.h"
#include "DNA_object_types.h"
#include "DNA_view3d_types.h"
#include "DNA_windowmanager_types.h"

#include "DRW_engine.h"

#include "ED_armature.h"
#include "ED_keyframing.h"
#include "ED_gpencil.h"
#include "ED_screen.h"
#include "ED_transform.h"

#include "DEG_depsgraph_query.h"

#include "GPU_batch.h"
#include "GPU_batch_presets.h"
#include "GPU_draw.h"
#include "GPU_matrix.h"
#include "GPU_immediate.h"
#include "GPU_immediate_util.h"
#include "GPU_material.h"
#include "GPU_viewport.h"
#include "GPU_state.h"
#include "GPU_framebuffer.h"

#include "MEM_guardedalloc.h"

#include "UI_interface.h"
#include "UI_resources.h"

#include "RE_engine.h"

#include "WM_api.h"
#include "WM_types.h"

#include "RNA_access.h"

#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"

#include "view3d_intern.h"  /* own include */

/* ******************** general functions ***************** */

/**
 * \note keep this synced with #ED_view3d_mats_rv3d_backup/#ED_view3d_mats_rv3d_restore
 */
void ED_view3d_update_viewmat(
        Depsgraph *depsgraph, Scene *scene, View3D *v3d, ARegion *ar,
        float viewmat[4][4], float winmat[4][4], const rcti *rect)
{
	RegionView3D *rv3d = ar->regiondata;

	/* setup window matrices */
	if (winmat)
		copy_m4_m4(rv3d->winmat, winmat);
	else
		view3d_winmatrix_set(depsgraph, ar, v3d, rect);

	/* setup view matrix */
	if (viewmat) {
		copy_m4_m4(rv3d->viewmat, viewmat);
	}
	else {
		float rect_scale[2];
		if (rect) {
			rect_scale[0] = (float)BLI_rcti_size_x(rect) / (float)ar->winx;
			rect_scale[1] = (float)BLI_rcti_size_y(rect) / (float)ar->winy;
		}
		/* note: calls BKE_object_where_is_calc for camera... */
		view3d_viewmatrix_set(depsgraph, scene, v3d, rv3d, rect ? rect_scale : NULL);
	}
	/* update utility matrices */
	mul_m4_m4m4(rv3d->persmat, rv3d->winmat, rv3d->viewmat);
	invert_m4_m4(rv3d->persinv, rv3d->persmat);
	invert_m4_m4(rv3d->viewinv, rv3d->viewmat);

	/* calculate GLSL view dependent values */

	/* store window coordinates scaling/offset */
	if (rv3d->persp == RV3D_CAMOB && v3d->camera) {
		rctf cameraborder;
		ED_view3d_calc_camera_border(scene, depsgraph, ar, v3d, rv3d, &cameraborder, false);
		rv3d->viewcamtexcofac[0] = (float)ar->winx / BLI_rctf_size_x(&cameraborder);
		rv3d->viewcamtexcofac[1] = (float)ar->winy / BLI_rctf_size_y(&cameraborder);

		rv3d->viewcamtexcofac[2] = -rv3d->viewcamtexcofac[0] * cameraborder.xmin / (float)ar->winx;
		rv3d->viewcamtexcofac[3] = -rv3d->viewcamtexcofac[1] * cameraborder.ymin / (float)ar->winy;
	}
	else {
		rv3d->viewcamtexcofac[0] = rv3d->viewcamtexcofac[1] = 1.0f;
		rv3d->viewcamtexcofac[2] = rv3d->viewcamtexcofac[3] = 0.0f;
	}

	/* calculate pixelsize factor once, is used for lamps and obcenters */
	{
		/* note:  '1.0f / len_v3(v1)'  replaced  'len_v3(rv3d->viewmat[0])'
		 * because of float point precision problems at large values [#23908] */
		float v1[3], v2[3];
		float len_px, len_sc;

		v1[0] = rv3d->persmat[0][0];
		v1[1] = rv3d->persmat[1][0];
		v1[2] = rv3d->persmat[2][0];

		v2[0] = rv3d->persmat[0][1];
		v2[1] = rv3d->persmat[1][1];
		v2[2] = rv3d->persmat[2][1];

		len_px = 2.0f / sqrtf(min_ff(len_squared_v3(v1), len_squared_v3(v2)));
		len_sc = (float)MAX2(ar->winx, ar->winy);

		rv3d->pixsize = len_px / len_sc;
	}
}

static void view3d_main_region_setup_view(
        Depsgraph *depsgraph, Scene *scene,
        View3D *v3d, ARegion *ar, float viewmat[4][4], float winmat[4][4], const rcti *rect)
{
	RegionView3D *rv3d = ar->regiondata;

	ED_view3d_update_viewmat(depsgraph, scene, v3d, ar, viewmat, winmat, rect);

	/* set for opengl */
	gpuLoadProjectionMatrix(rv3d->winmat);
	gpuLoadMatrix(rv3d->viewmat);
}

static bool view3d_stereo3d_active(wmWindow *win, Scene *scene, View3D *v3d, RegionView3D *rv3d)
{
	if ((scene->r.scemode & R_MULTIVIEW) == 0) {
		return false;
	}

	if ((v3d->camera == NULL) || (v3d->camera->type != OB_CAMERA) || rv3d->persp != RV3D_CAMOB) {
		return false;
	}

	switch (v3d->stereo3d_camera) {
		case STEREO_MONO_ID:
			return false;
			break;
		case STEREO_3D_ID:
			/* win will be NULL when calling this from the selection or draw loop. */
			if ((win == NULL) || (WM_stereo3d_enabled(win, true) == false)) {
				return false;
			}
			if (((scene->r.views_format & SCE_VIEWS_FORMAT_MULTIVIEW) != 0) &&
			    !BKE_scene_multiview_is_stereo3d(&scene->r))
			{
				return false;
			}
			break;
		/* We always need the stereo calculation for left and right cameras. */
		case STEREO_LEFT_ID:
		case STEREO_RIGHT_ID:
		default:
			break;
	}
	return true;
}


/* setup the view and win matrices for the multiview cameras
 *
 * unlike view3d_stereo3d_setup_offscreen, when view3d_stereo3d_setup is called
 * we have no winmatrix (i.e., projection matrix) defined at that time.
 * Since the camera and the camera shift are needed for the winmat calculation
 * we do a small hack to replace it temporarily so we don't need to change the
 * view3d)main_region_setup_view() code to account for that.
 */
static void view3d_stereo3d_setup(
        Depsgraph *depsgraph, Scene *scene, View3D *v3d, ARegion *ar, const rcti *rect)
{
	bool is_left;
	const char *names[2] = { STEREO_LEFT_NAME, STEREO_RIGHT_NAME };
	const char *viewname;

	/* show only left or right camera */
	if (v3d->stereo3d_camera != STEREO_3D_ID)
		v3d->multiview_eye = v3d->stereo3d_camera;

	is_left = v3d->multiview_eye == STEREO_LEFT_ID;
	viewname = names[is_left ? STEREO_LEFT_ID : STEREO_RIGHT_ID];

	/* update the viewport matrices with the new camera */
	if (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D) {
		Camera *data;
		float viewmat[4][4];
		float shiftx;

		data = (Camera *)v3d->camera->data;
		shiftx = data->shiftx;

		BLI_thread_lock(LOCK_VIEW3D);
		data->shiftx = BKE_camera_multiview_shift_x(&scene->r, v3d->camera, viewname);

		BKE_camera_multiview_view_matrix(&scene->r, v3d->camera, is_left, viewmat);
		view3d_main_region_setup_view(depsgraph, scene, v3d, ar, viewmat, NULL, rect);

		data->shiftx = shiftx;
		BLI_thread_unlock(LOCK_VIEW3D);
	}
	else { /* SCE_VIEWS_FORMAT_MULTIVIEW */
		float viewmat[4][4];
		Object *view_ob = v3d->camera;
		Object *camera = BKE_camera_multiview_render(scene, v3d->camera, viewname);

		BLI_thread_lock(LOCK_VIEW3D);
		v3d->camera = camera;

		BKE_camera_multiview_view_matrix(&scene->r, camera, false, viewmat);
		view3d_main_region_setup_view(depsgraph, scene, v3d, ar, viewmat, NULL, rect);

		v3d->camera = view_ob;
		BLI_thread_unlock(LOCK_VIEW3D);
	}
}

/**
 * Set the correct matrices
 */
void ED_view3d_draw_setup_view(
        wmWindow *win, Depsgraph *depsgraph, Scene *scene, ARegion *ar, View3D *v3d,
        float viewmat[4][4], float winmat[4][4], const rcti *rect)
{
	RegionView3D *rv3d = ar->regiondata;

	/* Setup the view matrix. */
	if (view3d_stereo3d_active(win, scene, v3d, rv3d)) {
		view3d_stereo3d_setup(depsgraph, scene, v3d, ar, rect);
	}
	else {
		view3d_main_region_setup_view(depsgraph, scene, v3d, ar, viewmat, winmat, rect);
	}
}

/* ******************** view border ***************** */

static void view3d_camera_border(
        const Scene *scene, struct Depsgraph *depsgraph,
        const ARegion *ar, const View3D *v3d, const RegionView3D *rv3d,
        rctf *r_viewborder, const bool no_shift, const bool no_zoom)
{
	CameraParams params;
	rctf rect_view, rect_camera;
	Object *camera_eval = DEG_get_evaluated_object(depsgraph, v3d->camera);

	/* get viewport viewplane */
	BKE_camera_params_init(&params);
	BKE_camera_params_from_view3d(&params, depsgraph, v3d, rv3d);
	if (no_zoom)
		params.zoom = 1.0f;
	BKE_camera_params_compute_viewplane(&params, ar->winx, ar->winy, 1.0f, 1.0f);
	rect_view = params.viewplane;

	/* get camera viewplane */
	BKE_camera_params_init(&params);
	/* fallback for non camera objects */
	params.clipsta = v3d->near;
	params.clipend = v3d->far;
	BKE_camera_params_from_object(&params, camera_eval);
	if (no_shift) {
		params.shiftx = 0.0f;
		params.shifty = 0.0f;
	}
	BKE_camera_params_compute_viewplane(&params, scene->r.xsch, scene->r.ysch, scene->r.xasp, scene->r.yasp);
	rect_camera = params.viewplane;

	/* get camera border within viewport */
	r_viewborder->xmin = ((rect_camera.xmin - rect_view.xmin) / BLI_rctf_size_x(&rect_view)) * ar->winx;
	r_viewborder->xmax = ((rect_camera.xmax - rect_view.xmin) / BLI_rctf_size_x(&rect_view)) * ar->winx;
	r_viewborder->ymin = ((rect_camera.ymin - rect_view.ymin) / BLI_rctf_size_y(&rect_view)) * ar->winy;
	r_viewborder->ymax = ((rect_camera.ymax - rect_view.ymin) / BLI_rctf_size_y(&rect_view)) * ar->winy;
}

void ED_view3d_calc_camera_border_size(
        const Scene *scene, Depsgraph *depsgraph,
        const ARegion *ar, const View3D *v3d, const RegionView3D *rv3d,
        float r_size[2])
{
	rctf viewborder;

	view3d_camera_border(scene, depsgraph, ar, v3d, rv3d, &viewborder, true, true);
	r_size[0] = BLI_rctf_size_x(&viewborder);
	r_size[1] = BLI_rctf_size_y(&viewborder);
}

void ED_view3d_calc_camera_border(
        const Scene *scene, Depsgraph *depsgraph,
        const ARegion *ar, const View3D *v3d, const RegionView3D *rv3d,
        rctf *r_viewborder, const bool no_shift)
{
	view3d_camera_border(scene, depsgraph, ar, v3d, rv3d, r_viewborder, no_shift, false);
}

static void drawviewborder_grid3(uint shdr_pos, float x1, float x2, float y1, float y2, float fac)
{
	float x3, y3, x4, y4;

	x3 = x1 + fac * (x2 - x1);
	y3 = y1 + fac * (y2 - y1);
	x4 = x1 + (1.0f - fac) * (x2 - x1);
	y4 = y1 + (1.0f - fac) * (y2 - y1);

	immBegin(GWN_PRIM_LINES, 8);

	immVertex2f(shdr_pos, x1, y3);
	immVertex2f(shdr_pos, x2, y3);

	immVertex2f(shdr_pos, x1, y4);
	immVertex2f(shdr_pos, x2, y4);

	immVertex2f(shdr_pos, x3, y1);
	immVertex2f(shdr_pos, x3, y2);

	immVertex2f(shdr_pos, x4, y1);
	immVertex2f(shdr_pos, x4, y2);

	immEnd();
}

/* harmonious triangle */
static void drawviewborder_triangle(
        uint shdr_pos, float x1, float x2, float y1, float y2, const char golden, const char dir)
{
	float ofs;
	float w = x2 - x1;
	float h = y2 - y1;

	immBegin(GWN_PRIM_LINES, 6);

	if (w > h) {
		if (golden) {
			ofs = w * (1.0f - (1.0f / 1.61803399f));
		}
		else {
			ofs = h * (h / w);
		}
		if (dir == 'B') SWAP(float, y1, y2);

		immVertex2f(shdr_pos, x1, y1);
		immVertex2f(shdr_pos, x2, y2);

		immVertex2f(shdr_pos, x2, y1);
		immVertex2f(shdr_pos, x1 + (w - ofs), y2);

		immVertex2f(shdr_pos, x1, y2);
		immVertex2f(shdr_pos, x1 + ofs, y1);
	}
	else {
		if (golden) {
			ofs = h * (1.0f - (1.0f / 1.61803399f));
		}
		else {
			ofs = w * (w / h);
		}
		if (dir == 'B') SWAP(float, x1, x2);

		immVertex2f(shdr_pos, x1, y1);
		immVertex2f(shdr_pos, x2, y2);

		immVertex2f(shdr_pos, x2, y1);
		immVertex2f(shdr_pos, x1, y1 + ofs);

		immVertex2f(shdr_pos, x1, y2);
		immVertex2f(shdr_pos, x2, y1 + (h - ofs));
	}

	immEnd();
}

static void drawviewborder(Scene *scene, Depsgraph *depsgraph, ARegion *ar, View3D *v3d)
{
	float x1, x2, y1, y2;
	float x1i, x2i, y1i, y2i;

	rctf viewborder;
	Camera *ca = NULL;
	RegionView3D *rv3d = ar->regiondata;

	if (v3d->camera == NULL)
		return;
	if (v3d->camera->type == OB_CAMERA)
		ca = v3d->camera->data;

	ED_view3d_calc_camera_border(scene, depsgraph, ar, v3d, rv3d, &viewborder, false);
	/* the offsets */
	x1 = viewborder.xmin;
	y1 = viewborder.ymin;
	x2 = viewborder.xmax;
	y2 = viewborder.ymax;

	GPU_line_width(1.0f);

	/* apply offsets so the real 3D camera shows through */

	/* note: quite un-scientific but without this bit extra
	 * 0.0001 on the lower left the 2D border sometimes
	 * obscures the 3D camera border */
	/* note: with VIEW3D_CAMERA_BORDER_HACK defined this error isn't noticeable
	 * but keep it here in case we need to remove the workaround */
	x1i = (int)(x1 - 1.0001f);
	y1i = (int)(y1 - 1.0001f);
	x2i = (int)(x2 + (1.0f - 0.0001f));
	y2i = (int)(y2 + (1.0f - 0.0001f));

	uint shdr_pos = GWN_vertformat_attr_add(immVertexFormat(), "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);

	/* First, solid lines. */
	{
		immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

		/* passepartout, specified in camera edit buttons */
		if (ca && (ca->flag & CAM_SHOWPASSEPARTOUT) && ca->passepartalpha > 0.000001f) {
			const float winx = (ar->winx + 1);
			const float winy = (ar->winy + 1);

			float alpha = 1.0f;

			if (ca->passepartalpha != 1.0f) {
				GPU_blend_set_func_separate(GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);
				GPU_blend(true);
				alpha = ca->passepartalpha;
			}

			immUniformColor4f(0.0f, 0.0f, 0.0f, alpha);

			if (x1i > 0.0f)
				immRectf(shdr_pos, 0.0f, winy, x1i, 0.0f);
			if (x2i < winx)
				immRectf(shdr_pos, x2i, winy, winx, 0.0f);
			if (y2i < winy)
				immRectf(shdr_pos, x1i, winy, x2i, y2i);
			if (y2i > 0.0f)
				immRectf(shdr_pos, x1i, y1i, x2i, 0.0f);

			GPU_blend(false);
		}

		immUniformThemeColor(TH_BACK);
		imm_draw_box_wire_2d(shdr_pos, x1i, y1i, x2i, y2i);

#ifdef VIEW3D_CAMERA_BORDER_HACK
		if (view3d_camera_border_hack_test == true) {
			immUniformColor3ubv(view3d_camera_border_hack_col);
			imm_draw_box_wire_2d(shdr_pos, x1i + 1, y1i + 1, x2i - 1, y2i - 1);
			view3d_camera_border_hack_test = false;
		}
#endif

		immUnbindProgram();
	}

	/* And now, the dashed lines! */
	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);

	{
		float viewport_size[4];
		GPU_viewport_size_get_f(viewport_size);
		immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);

		immUniform1i("colors_len", 0);  /* "simple" mode */
		immUniform1f("dash_width", 6.0f);
		immUniform1f("dash_factor", 0.5f);

		/* outer line not to confuse with object selection */
		if (v3d->flag2 & V3D_LOCK_CAMERA) {
			immUniformThemeColor(TH_REDALERT);
			imm_draw_box_wire_2d(shdr_pos, x1i - 1, y1i - 1, x2i + 1, y2i + 1);
		}

		immUniformThemeColor(TH_VIEW_OVERLAY);
		imm_draw_box_wire_2d(shdr_pos, x1i, y1i, x2i, y2i);
	}

	/* border */
	if (scene->r.mode & R_BORDER) {
		float x3, y3, x4, y4;

		x3 = floorf(x1 + (scene->r.border.xmin * (x2 - x1))) - 1;
		y3 = floorf(y1 + (scene->r.border.ymin * (y2 - y1))) - 1;
		x4 = floorf(x1 + (scene->r.border.xmax * (x2 - x1))) + (U.pixelsize - 1);
		y4 = floorf(y1 + (scene->r.border.ymax * (y2 - y1))) + (U.pixelsize - 1);

		immUniformColor3f(1.0f, 0.25f, 0.25f);
		imm_draw_box_wire_2d(shdr_pos, x3, y3, x4, y4);
	}

	/* safety border */
	if (ca) {
		immUniformThemeColorBlend(TH_VIEW_OVERLAY, TH_BACK, 0.25f);

		if (ca->dtx & CAM_DTX_CENTER) {
			float x3, y3;

			x3 = x1 + 0.5f * (x2 - x1);
			y3 = y1 + 0.5f * (y2 - y1);

			immBegin(GWN_PRIM_LINES, 4);

			immVertex2f(shdr_pos, x1, y3);
			immVertex2f(shdr_pos, x2, y3);

			immVertex2f(shdr_pos, x3, y1);
			immVertex2f(shdr_pos, x3, y2);

			immEnd();
		}

		if (ca->dtx & CAM_DTX_CENTER_DIAG) {
			immBegin(GWN_PRIM_LINES, 4);

			immVertex2f(shdr_pos, x1, y1);
			immVertex2f(shdr_pos, x2, y2);

			immVertex2f(shdr_pos, x1, y2);
			immVertex2f(shdr_pos, x2, y1);

			immEnd();
		}

		if (ca->dtx & CAM_DTX_THIRDS) {
			drawviewborder_grid3(shdr_pos, x1, x2, y1, y2, 1.0f / 3.0f);
		}

		if (ca->dtx & CAM_DTX_GOLDEN) {
			drawviewborder_grid3(shdr_pos, x1, x2, y1, y2, 1.0f - (1.0f / 1.61803399f));
		}

		if (ca->dtx & CAM_DTX_GOLDEN_TRI_A) {
			drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 0, 'A');
		}

		if (ca->dtx & CAM_DTX_GOLDEN_TRI_B) {
			drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 0, 'B');
		}

		if (ca->dtx & CAM_DTX_HARMONY_TRI_A) {
			drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 1, 'A');
		}

		if (ca->dtx & CAM_DTX_HARMONY_TRI_B) {
			drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 1, 'B');
		}

		if (ca->flag & CAM_SHOW_SAFE_MARGINS) {
			UI_draw_safe_areas(
			        shdr_pos, x1, x2, y1, y2,
			        scene->safe_areas.title, scene->safe_areas.action);

			if (ca->flag & CAM_SHOW_SAFE_CENTER) {
				UI_draw_safe_areas(
				        shdr_pos, x1, x2, y1, y2,
				        scene->safe_areas.title_center, scene->safe_areas.action_center);
			}
		}

		if (ca->flag & CAM_SHOWSENSOR) {
			/* determine sensor fit, and get sensor x/y, for auto fit we
			 * assume and square sensor and only use sensor_x */
			float sizex = scene->r.xsch * scene->r.xasp;
			float sizey = scene->r.ysch * scene->r.yasp;
			int sensor_fit = BKE_camera_sensor_fit(ca->sensor_fit, sizex, sizey);
			float sensor_x = ca->sensor_x;
			float sensor_y = (ca->sensor_fit == CAMERA_SENSOR_FIT_AUTO) ? ca->sensor_x : ca->sensor_y;

			/* determine sensor plane */
			rctf rect;

			if (sensor_fit == CAMERA_SENSOR_FIT_HOR) {
				float sensor_scale = (x2i - x1i) / sensor_x;
				float sensor_height = sensor_scale * sensor_y;

				rect.xmin = x1i;
				rect.xmax = x2i;
				rect.ymin = (y1i + y2i) * 0.5f - sensor_height * 0.5f;
				rect.ymax = rect.ymin + sensor_height;
			}
			else {
				float sensor_scale = (y2i - y1i) / sensor_y;
				float sensor_width = sensor_scale * sensor_x;

				rect.xmin = (x1i + x2i) * 0.5f - sensor_width * 0.5f;
				rect.xmax = rect.xmin + sensor_width;
				rect.ymin = y1i;
				rect.ymax = y2i;
			}

			/* draw */
			immUniformThemeColorShade(TH_VIEW_OVERLAY, 100);

			/* TODO Was using UI_draw_roundbox_4fv(false, rect.xmin, rect.ymin, rect.xmax, rect.ymax, 2.0f, color).
			 * We'll probably need a new imm_draw_line_roundbox_dashed dor that - though in practice the
			 * 2.0f round corner effect was nearly not visible anyway... */
			imm_draw_box_wire_2d(shdr_pos, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
		}
	}

	immUnbindProgram();
	/* end dashed lines */

	/* camera name - draw in highlighted text color */
	if (ca && (ca->flag & CAM_SHOWNAME)) {
		UI_FontThemeColor(BLF_default(), TH_TEXT_HI);
		BLF_draw_default(
		        x1i, y1i - (0.7f * U.widget_unit), 0.0f,
		        v3d->camera->id.name + 2, sizeof(v3d->camera->id.name) - 2);
	}
}

static void drawrenderborder(ARegion *ar, View3D *v3d)
{
	/* use the same program for everything */
	uint shdr_pos = GWN_vertformat_attr_add(immVertexFormat(), "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);

	GPU_line_width(1.0f);

	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);

	float viewport_size[4];
	GPU_viewport_size_get_f(viewport_size);
	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);

	immUniform1i("colors_len", 0);  /* "simple" mode */
	immUniform4f("color", 1.0f, 0.25f, 0.25f, 1.0f);
	immUniform1f("dash_width", 6.0f);
	immUniform1f("dash_factor", 0.5f);

	imm_draw_box_wire_2d(shdr_pos,
	                  v3d->render_border.xmin * ar->winx, v3d->render_border.ymin * ar->winy,
	                  v3d->render_border.xmax * ar->winx, v3d->render_border.ymax * ar->winy);

	immUnbindProgram();
}

void ED_view3d_draw_depth(
        Depsgraph *depsgraph,
        ARegion *ar, View3D *v3d, bool alphaoverride)
{
	struct bThemeState theme_state;
	Scene *scene = DEG_get_evaluated_scene(depsgraph);
	RegionView3D *rv3d = ar->regiondata;

	short flag = v3d->flag;
	float glalphaclip = U.glalphaclip;
	int obcenter_dia = U.obcenter_dia;
	/* temp set drawtype to solid */
	/* Setting these temporarily is not nice */
	v3d->flag &= ~V3D_SELECT_OUTLINE;
	U.glalphaclip = alphaoverride ? 0.5f : glalphaclip; /* not that nice but means we wont zoom into billboards */
	U.obcenter_dia = 0;

	/* Tools may request depth outside of regular drawing code. */
	UI_Theme_Store(&theme_state);
	UI_SetTheme(SPACE_VIEW3D, RGN_TYPE_WINDOW);

	ED_view3d_draw_setup_view(NULL, depsgraph, scene, ar, v3d, NULL, NULL, NULL);

	GPU_clear(GPU_DEPTH_BIT);

	if (rv3d->rflag & RV3D_CLIPPING) {
		ED_view3d_clipping_set(rv3d);
	}
	/* get surface depth without bias */
	rv3d->rflag |= RV3D_ZOFFSET_DISABLED;

	GPU_depth_test(true);

	DRW_draw_depth_loop(depsgraph, ar, v3d);

	if (rv3d->rflag & RV3D_CLIPPING) {
		ED_view3d_clipping_disable();
	}
	rv3d->rflag &= ~RV3D_ZOFFSET_DISABLED;

	/* Reset default for UI */
	GPU_depth_test(false);

	U.glalphaclip = glalphaclip;
	v3d->flag = flag;
	U.obcenter_dia = obcenter_dia;

	UI_Theme_Restore(&theme_state);
}

/* ******************** other elements ***************** */

/** could move this elsewhere, but tied into #ED_view3d_grid_scale */
float ED_scene_grid_scale(Scene *scene, const char **grid_unit)
{
	/* apply units */
	if (scene->unit.system) {
		const void *usys;
		int len;

		bUnit_GetSystem(scene->unit.system, B_UNIT_LENGTH, &usys, &len);

		if (usys) {
			int i = bUnit_GetBaseUnit(usys);
			if (grid_unit)
				*grid_unit = bUnit_GetNameDisplay(usys, i);
			return (float)bUnit_GetScaler(usys, i) / scene->unit.scale_length;
		}
	}

	return 1.0f;
}

float ED_view3d_grid_scale(Scene *scene, View3D *v3d, const char **grid_unit)
{
	return v3d->grid * ED_scene_grid_scale(scene, grid_unit);
}

static void draw_view_axis(RegionView3D *rv3d, const rcti *rect)
{
	const float k = U.rvisize * U.pixelsize;  /* axis size */
	const int bright = - 20 * (10 - U.rvibright);  /* axis alpha offset (rvibright has range 0-10) */

	/* Axis center in screen coordinates.
	 *
	 * - Unit size offset so small text doesn't draw outside the screen
	 * - Extra X offset because of the panel expander.
	 */
	const float startx = rect->xmax - (k + UI_UNIT_X * 1.5);
	const float starty = rect->ymax - (k + UI_UNIT_Y);

	float axis_pos[3][2];
	unsigned char axis_col[3][4];

	int axis_order[3] = {0, 1, 2};
	axis_sort_v3(rv3d->viewinv[2], axis_order);

	for (int axis_i = 0; axis_i < 3; axis_i++) {
		int i = axis_order[axis_i];

		/* get position of each axis tip on screen */
		float vec[3] = { 0.0f };
		vec[i] = 1.0f;
		mul_qt_v3(rv3d->viewquat, vec);
		axis_pos[i][0] = startx + vec[0] * k;
		axis_pos[i][1] = starty + vec[1] * k;

		/* get color of each axis */
		UI_GetThemeColorShade3ubv(TH_AXIS_X + i, bright, axis_col[i]); /* rgb */
		axis_col[i][3] = 255 * hypotf(vec[0], vec[1]); /* alpha */
	}

	/* draw axis lines */
	GPU_line_width(2.0f);
	GPU_line_smooth(true);
	GPU_blend(true);
	GPU_blend_set_func_separate(GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);

	Gwn_VertFormat *format = immVertexFormat();
	uint pos = GWN_vertformat_attr_add(format, "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
	uint col = GWN_vertformat_attr_add(format, "color", GWN_COMP_U8, 4, GWN_FETCH_INT_TO_FLOAT_UNIT);

	immBindBuiltinProgram(GPU_SHADER_2D_FLAT_COLOR);
	immBegin(GWN_PRIM_LINES, 6);

	for (int axis_i = 0; axis_i < 3; axis_i++) {
		int i = axis_order[axis_i];

		immAttrib4ubv(col, axis_col[i]);
		immVertex2f(pos, startx, starty);
		immAttrib4ubv(col, axis_col[i]);
		immVertex2fv(pos, axis_pos[i]);
	}

	immEnd();
	immUnbindProgram();
	GPU_line_smooth(false);

	/* draw axis names */
	for (int axis_i = 0; axis_i < 3; axis_i++) {
		int i = axis_order[axis_i];

		const char axis_text[2] = {'x' + i, '\0'};
		BLF_color4ubv(BLF_default(), axis_col[i]);
		BLF_draw_default_ascii(axis_pos[i][0] + 2, axis_pos[i][1] + 2, 0.0f, axis_text, 1);
	}
}

#ifdef WITH_INPUT_NDOF
/* draw center and axis of rotation for ongoing 3D mouse navigation */
static void UNUSED_FUNCTION(draw_rotation_guide)(RegionView3D *rv3d)
{
	float o[3];    /* center of rotation */
	float end[3];  /* endpoints for drawing */

	GLubyte color[4] = {0, 108, 255, 255};  /* bright blue so it matches device LEDs */

	negate_v3_v3(o, rv3d->ofs);

	GPU_blend(true);
	GPU_blend_set_func_separate(GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);
	glDepthMask(GL_FALSE);  /* don't overwrite zbuf */

	Gwn_VertFormat *format = immVertexFormat();
	uint pos = GWN_vertformat_attr_add(format, "pos", GWN_COMP_F32, 3, GWN_FETCH_FLOAT);
	uint col = GWN_vertformat_attr_add(format, "color", GWN_COMP_U8, 4, GWN_FETCH_INT_TO_FLOAT_UNIT);

	immBindBuiltinProgram(GPU_SHADER_3D_SMOOTH_COLOR);

	if (rv3d->rot_angle != 0.0f) {
		/* -- draw rotation axis -- */
		float scaled_axis[3];
		const float scale = rv3d->dist;
		mul_v3_v3fl(scaled_axis, rv3d->rot_axis, scale);


		immBegin(GWN_PRIM_LINE_STRIP, 3);
		color[3] = 0; /* more transparent toward the ends */
		immAttrib4ubv(col, color);
		add_v3_v3v3(end, o, scaled_axis);
		immVertex3fv(pos, end);

#if 0
		color[3] = 0.2f + fabsf(rv3d->rot_angle);  /* modulate opacity with angle */
		/* ^^ neat idea, but angle is frame-rate dependent, so it's usually close to 0.2 */
#endif

		color[3] = 127; /* more opaque toward the center */
		immAttrib4ubv(col, color);
		immVertex3fv(pos, o);

		color[3] = 0;
		immAttrib4ubv(col, color);
		sub_v3_v3v3(end, o, scaled_axis);
		immVertex3fv(pos, end);
		immEnd();

		/* -- draw ring around rotation center -- */
		{
#define     ROT_AXIS_DETAIL 13

			const float s = 0.05f * scale;
			const float step = 2.0f * (float)(M_PI / ROT_AXIS_DETAIL);

			float q[4];  /* rotate ring so it's perpendicular to axis */
			const int upright = fabsf(rv3d->rot_axis[2]) >= 0.95f;
			if (!upright) {
				const float up[3] = {0.0f, 0.0f, 1.0f};
				float vis_angle, vis_axis[3];

				cross_v3_v3v3(vis_axis, up, rv3d->rot_axis);
				vis_angle = acosf(dot_v3v3(up, rv3d->rot_axis));
				axis_angle_to_quat(q, vis_axis, vis_angle);
			}

			immBegin(GWN_PRIM_LINE_LOOP, ROT_AXIS_DETAIL);
			color[3] = 63; /* somewhat faint */
			immAttrib4ubv(col, color);
			float angle = 0.0f;
			for (int i = 0; i < ROT_AXIS_DETAIL; ++i, angle += step) {
				float p[3] = {s * cosf(angle), s * sinf(angle), 0.0f};

				if (!upright) {
					mul_qt_v3(q, p);
				}

				add_v3_v3(p, o);
				immVertex3fv(pos, p);
			}
			immEnd();

#undef      ROT_AXIS_DETAIL
		}

		color[3] = 255;  /* solid dot */
	}
	else
		color[3] = 127;  /* see-through dot */

	immUnbindProgram();

	/* -- draw rotation center -- */
	immBindBuiltinProgram(GPU_SHADER_3D_POINT_FIXED_SIZE_VARYING_COLOR);
	GPU_point_size(5.0f);
	immBegin(GWN_PRIM_POINTS, 1);
	immAttrib4ubv(col, color);
	immVertex3fv(pos, o);
	immEnd();
	immUnbindProgram();

#if 0
	/* find screen coordinates for rotation center, then draw pretty icon */
	mul_m4_v3(rv3d->persinv, rot_center);
	UI_icon_draw(rot_center[0], rot_center[1], ICON_NDOF_TURN);
	/* ^^ just playing around, does not work */
#endif

	GPU_blend(false);
	glDepthMask(GL_TRUE);
}
#endif /* WITH_INPUT_NDOF */

/* ******************** info ***************** */

/**
* Render and camera border
*/
static void view3d_draw_border(const bContext *C, ARegion *ar)
{
	Scene *scene = CTX_data_scene(C);
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	RegionView3D *rv3d = ar->regiondata;
	View3D *v3d = CTX_wm_view3d(C);

	if (rv3d->persp == RV3D_CAMOB) {
		drawviewborder(scene, depsgraph, ar, v3d);
	}
	else if (v3d->flag2 & V3D_RENDER_BORDER) {
		drawrenderborder(ar, v3d);
	}
}

/**
* Grease Pencil
*/
static void view3d_draw_grease_pencil(const bContext *UNUSED(C))
{
	/* TODO viewport */
}

/**
* Viewport Name
*/
static const char *view3d_get_name(View3D *v3d, RegionView3D *rv3d)
{
	const char *name = NULL;

	switch (rv3d->view) {
		case RV3D_VIEW_FRONT:
			if (rv3d->persp == RV3D_ORTHO) name = IFACE_("Front Ortho");
			else name = IFACE_("Front Persp");
			break;
		case RV3D_VIEW_BACK:
			if (rv3d->persp == RV3D_ORTHO) name = IFACE_("Back Ortho");
			else name = IFACE_("Back Persp");
			break;
		case RV3D_VIEW_TOP:
			if (rv3d->persp == RV3D_ORTHO) name = IFACE_("Top Ortho");
			else name = IFACE_("Top Persp");
			break;
		case RV3D_VIEW_BOTTOM:
			if (rv3d->persp == RV3D_ORTHO) name = IFACE_("Bottom Ortho");
			else name = IFACE_("Bottom Persp");
			break;
		case RV3D_VIEW_RIGHT:
			if (rv3d->persp == RV3D_ORTHO) name = IFACE_("Right Ortho");
			else name = IFACE_("Right Persp");
			break;
		case RV3D_VIEW_LEFT:
			if (rv3d->persp == RV3D_ORTHO) name = IFACE_("Left Ortho");
			else name = IFACE_("Left Persp");
			break;

		default:
			if (rv3d->persp == RV3D_CAMOB) {
				if ((v3d->camera) && (v3d->camera->type == OB_CAMERA)) {
					Camera *cam;
					cam = v3d->camera->data;
					if (cam->type == CAM_PERSP) {
						name = IFACE_("Camera Persp");
					}
					else if (cam->type == CAM_ORTHO) {
						name = IFACE_("Camera Ortho");
					}
					else {
						BLI_assert(cam->type == CAM_PANO);
						name = IFACE_("Camera Pano");
					}
				}
				else {
					name = IFACE_("Object as Camera");
				}
			}
			else {
				name = (rv3d->persp == RV3D_ORTHO) ? IFACE_("User Ortho") : IFACE_("User Persp");
			}
	}

	return name;
}

static void draw_viewport_name(ARegion *ar, View3D *v3d, const rcti *rect)
{
	RegionView3D *rv3d = ar->regiondata;
	const char *name = view3d_get_name(v3d, rv3d);
	/* increase size for unicode languages (Chinese in utf-8...) */
#ifdef WITH_INTERNATIONAL
	char tmpstr[96];
#else
	char tmpstr[32];
#endif

	if (v3d->localvd) {
		BLI_snprintf(tmpstr, sizeof(tmpstr), IFACE_("%s (Local)"), name);
		name = tmpstr;
	}

	UI_FontThemeColor(BLF_default(), TH_TEXT_HI);
#ifdef WITH_INTERNATIONAL
	BLF_draw_default(U.widget_unit + rect->xmin,  rect->ymax - U.widget_unit, 0.0f, name, sizeof(tmpstr));
#else
	BLF_draw_default_ascii(U.widget_unit + rect->xmin,  rect->ymax - U.widget_unit, 0.0f, name, sizeof(tmpstr));
#endif
}

/**
 * draw info beside axes in bottom left-corner:
 * framenum, object name, bone name (if available), marker name (if available)
 */

static void draw_selected_name(Scene *scene, Object *ob, rcti *rect)
{
	const int cfra = CFRA;
	const char *msg_pin = " (Pinned)";
	const char *msg_sep = " : ";

	const int font_id = BLF_default();

	char info[300];
	char *s = info;

	s += sprintf(s, "(%d)", cfra);

	/*
	 * info can contain:
	 * - a frame (7 + 2)
	 * - 3 object names (MAX_NAME)
	 * - 2 BREAD_CRUMB_SEPARATORs (6)
	 * - a SHAPE_KEY_PINNED marker and a trailing '\0' (9+1) - translated, so give some room!
	 * - a marker name (MAX_NAME + 3)
	 */

	/* get name of marker on current frame (if available) */
	const char *markern = BKE_scene_find_marker_name(scene, cfra);

	/* check if there is an object */
	if (ob) {
		*s++ = ' ';
		s += BLI_strcpy_rlen(s, ob->id.name + 2);

		/* name(s) to display depends on type of object */
		if (ob->type == OB_ARMATURE) {
			bArmature *arm = ob->data;

			/* show name of active bone too (if possible) */
			if (arm->edbo) {
				if (arm->act_edbone) {
					s += BLI_strcpy_rlen(s, msg_sep);
					s += BLI_strcpy_rlen(s, arm->act_edbone->name);
				}
			}
			else if (ob->mode & OB_MODE_POSE) {
				if (arm->act_bone) {

					if (arm->act_bone->layer & arm->layer) {
						s += BLI_strcpy_rlen(s, msg_sep);
						s += BLI_strcpy_rlen(s, arm->act_bone->name);
					}
				}
			}
		}
		else if (ELEM(ob->type, OB_MESH, OB_LATTICE, OB_CURVE)) {
			/* try to display active bone and active shapekey too (if they exist) */

			if (ob->type == OB_MESH && ob->mode & OB_MODE_WEIGHT_PAINT) {
				Object *armobj = BKE_object_pose_armature_get(ob);
				if (armobj  && armobj->mode & OB_MODE_POSE) {
					bArmature *arm = armobj->data;
					if (arm->act_bone) {
						if (arm->act_bone->layer & arm->layer) {
							s += BLI_strcpy_rlen(s, msg_sep);
							s += BLI_strcpy_rlen(s, arm->act_bone->name);
						}
					}
				}
			}

			Key *key = BKE_key_from_object(ob);
			if (key) {
				KeyBlock *kb = BLI_findlink(&key->block, ob->shapenr - 1);
				if (kb) {
					s += BLI_strcpy_rlen(s, msg_sep);
					s += BLI_strcpy_rlen(s, kb->name);
					if (ob->shapeflag & OB_SHAPE_LOCK) {
						s += BLI_strcpy_rlen(s, IFACE_(msg_pin));
					}
				}
			}
		}

		/* color depends on whether there is a keyframe */
		if (id_frame_has_keyframe((ID *)ob, /* BKE_scene_frame_get(scene) */ (float)cfra, ANIMFILTER_KEYS_LOCAL))
			UI_FontThemeColor(font_id, TH_TIME_KEYFRAME);
		else if (ED_gpencil_has_keyframe_v3d(scene, ob, cfra))
			UI_FontThemeColor(font_id, TH_TIME_GP_KEYFRAME);
		else
			UI_FontThemeColor(font_id, TH_TEXT_HI);
	}
	else {
		/* no object */
		if (ED_gpencil_has_keyframe_v3d(scene, NULL, cfra))
			UI_FontThemeColor(font_id, TH_TIME_GP_KEYFRAME);
		else
			UI_FontThemeColor(font_id, TH_TEXT_HI);
	}

	if (markern) {
		s += sprintf(s, " <%s>", markern);
	}

	BLF_draw_default(rect->xmin + UI_UNIT_X, rect->ymax - (2 * U.widget_unit), 0.0f, info, sizeof(info));
}

/* ******************** view loop ***************** */

/**
* Information drawn on top of the solid plates and composed data
*/
void view3d_draw_region_info(const bContext *C, ARegion *ar, const int UNUSED(offset))
{
	RegionView3D *rv3d = ar->regiondata;
	View3D *v3d = CTX_wm_view3d(C);
	Scene *scene = CTX_data_scene(C);
	wmWindowManager *wm = CTX_wm_manager(C);

	/* correct projection matrix */
	ED_region_pixelspace(ar);

	/* local coordinate visible rect inside region, to accomodate overlapping ui */
	rcti rect;
	ED_region_visible_rect(ar, &rect);


	view3d_draw_border(C, ar);
	view3d_draw_grease_pencil(C);

	BLF_batch_draw_begin();

	if ((U.uiflag & USER_SHOW_GIZMO_AXIS) ||
	    (v3d->flag2 & V3D_RENDER_OVERRIDE) ||
	    /* No need to display gizmo and this info. */
	    (v3d->mpr_flag & (V3D_GIZMO_HIDE | V3D_GIZMO_HIDE_NAVIGATE)))
	{
		/* pass */
	}
	else {
		draw_view_axis(rv3d, &rect);
	}

	if ((v3d->flag2 & V3D_RENDER_OVERRIDE) == 0 &&
	    (v3d->overlay.flag & V3D_OVERLAY_HIDE_TEXT) == 0)
	{
		if ((U.uiflag & USER_SHOW_FPS) && ED_screen_animation_no_scrub(wm)) {
			ED_scene_draw_fps(scene, &rect);
		}
		else if (U.uiflag & USER_SHOW_VIEWPORTNAME) {
			draw_viewport_name(ar, v3d, &rect);
		}

		if (U.uiflag & USER_DRAWVIEWINFO) {
			ViewLayer *view_layer = CTX_data_view_layer(C);
			Object *ob = OBACT(view_layer);
			draw_selected_name(scene, ob, &rect);
		}

#if 0 /* TODO */
		if (grid_unit) { /* draw below the viewport name */
			char numstr[32] = "";

			UI_FontThemeColor(BLF_default(), TH_TEXT_HI);
			if (v3d->grid != 1.0f) {
				BLI_snprintf(numstr, sizeof(numstr), "%s x %.4g", grid_unit, v3d->grid);
			}

			BLF_draw_default_ascii(
			        rect.xmin + U.widget_unit,
			        rect.ymax - (USER_SHOW_VIEWPORTNAME ? 2 * U.widget_unit : U.widget_unit), 0.0f,
			        numstr[0] ? numstr : grid_unit, sizeof(numstr));
		}
#endif
	}

	BLF_batch_draw_end();
}

static void view3d_draw_view(const bContext *C, ARegion *ar)
{
	ED_view3d_draw_setup_view(CTX_wm_window(C), CTX_data_depsgraph(C), CTX_data_scene(C), ar, CTX_wm_view3d(C), NULL, NULL, NULL);

	/* Only 100% compliant on new spec goes bellow */
	DRW_draw_view(C);
}

RenderEngineType *ED_view3d_engine_type(Scene *scene, int drawtype)
{
	/*
	 * Tempory viewport draw modes until we have a proper system.
	 * all modes are done in the draw manager, except
	 * cycles material as it is an external render engine.
	 */
	if (strcmp(scene->r.engine, RE_engine_id_CYCLES) == 0 && drawtype == OB_MATERIAL) {
		return RE_engines_find(RE_engine_id_BLENDER_EEVEE);
	}
	return RE_engines_find(scene->r.engine);
}

void view3d_main_region_draw(const bContext *C, ARegion *ar)
{
	Main *bmain = CTX_data_main(C);
	View3D *v3d = CTX_wm_view3d(C);

	view3d_draw_view(C, ar);

	GPU_free_images_old(bmain);
	GPU_pass_cache_garbage_collect();

	/* XXX This is in order to draw UI batches with the DRW
	 * olg context since we now use it for drawing the entire area */
	gpu_batch_presets_reset();

	/* No depth test for drawing action zones afterwards. */
	GPU_depth_test(false);

	v3d->flag |= V3D_INVALID_BACKBUF;
}

/* -------------------------------------------------------------------- */

/** \name Offscreen Drawing
 * \{ */

static void view3d_stereo3d_setup_offscreen(
        Depsgraph *depsgraph, Scene *scene, View3D *v3d, ARegion *ar,
        float winmat[4][4], const char *viewname)
{
	/* update the viewport matrices with the new camera */
	if (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D) {
		float viewmat[4][4];
		const bool is_left = STREQ(viewname, STEREO_LEFT_NAME);

		BKE_camera_multiview_view_matrix(&scene->r, v3d->camera, is_left, viewmat);
		view3d_main_region_setup_view(depsgraph, scene, v3d, ar, viewmat, winmat, NULL);
	}
	else { /* SCE_VIEWS_FORMAT_MULTIVIEW */
		float viewmat[4][4];
		Object *camera = BKE_camera_multiview_render(scene, v3d->camera, viewname);

		BKE_camera_multiview_view_matrix(&scene->r, camera, false, viewmat);
		view3d_main_region_setup_view(depsgraph, scene, v3d, ar, viewmat, winmat, NULL);
	}
}

void ED_view3d_draw_offscreen(
        Depsgraph *depsgraph, Scene *scene,
        int drawtype,
        View3D *v3d, ARegion *ar, int winx, int winy,
        float viewmat[4][4], float winmat[4][4],
        bool do_sky, bool UNUSED(is_persp), const char *viewname,
        GPUFXSettings *UNUSED(fx_settings),
        GPUOffScreen *ofs, GPUViewport *viewport)
{
	RegionView3D *rv3d = ar->regiondata;
	RenderEngineType *engine_type = ED_view3d_engine_type(scene, drawtype);

	/* set temporary new size */
	int bwinx = ar->winx;
	int bwiny = ar->winy;
	rcti brect = ar->winrct;

	ar->winx = winx;
	ar->winy = winy;
	ar->winrct.xmin = 0;
	ar->winrct.ymin = 0;
	ar->winrct.xmax = winx;
	ar->winrct.ymax = winy;

	struct bThemeState theme_state;
	UI_Theme_Store(&theme_state);
	UI_SetTheme(SPACE_VIEW3D, RGN_TYPE_WINDOW);

	/* set flags */
	G.f |= G_RENDER_OGL;

	if ((v3d->flag2 & V3D_RENDER_SHADOW) == 0) {
		/* free images which can have changed on frame-change
		 * warning! can be slow so only free animated images - campbell */
		GPU_free_images_anim(G.main);  /* XXX :((( */
	}

	gpuPushProjectionMatrix();
	gpuLoadIdentity();
	gpuPushMatrix();
	gpuLoadIdentity();

	if ((viewname != NULL && viewname[0] != '\0') && (viewmat == NULL) && rv3d->persp == RV3D_CAMOB && v3d->camera)
		view3d_stereo3d_setup_offscreen(depsgraph, scene, v3d, ar, winmat, viewname);
	else
		view3d_main_region_setup_view(depsgraph, scene, v3d, ar, viewmat, winmat, NULL);

	/* main drawing call */
	DRW_draw_render_loop_offscreen(
	        depsgraph, engine_type, ar, v3d,
	        do_sky, ofs, viewport);

	/* restore size */
	ar->winx = bwinx;
	ar->winy = bwiny;
	ar->winrct = brect;

	gpuPopProjectionMatrix();
	gpuPopMatrix();

	UI_Theme_Restore(&theme_state);

	G.f &= ~G_RENDER_OGL;
}

/**
 * Utility func for ED_view3d_draw_offscreen
 *
 * \param ofs: Optional off-screen buffer, can be NULL.
 * (avoids re-creating when doing multiple GL renders).
 */
ImBuf *ED_view3d_draw_offscreen_imbuf(
        Depsgraph *depsgraph, Scene *scene,
        int drawtype,
        View3D *v3d, ARegion *ar, int sizex, int sizey,
        unsigned int flag, unsigned int draw_flags,
        int alpha_mode, int samples, const char *viewname,
        /* output vars */
        GPUOffScreen *ofs, char err_out[256])
{
	RegionView3D *rv3d = ar->regiondata;
	const bool draw_sky = (alpha_mode == R_ADDSKY);
	const bool use_full_sample = (draw_flags & V3D_OFSDRAW_USE_FULL_SAMPLE);

	/* view state */
	GPUFXSettings fx_settings = v3d->fx_settings;
	bool is_ortho = false;
	float winmat[4][4];

	if (ofs && ((GPU_offscreen_width(ofs) != sizex) || (GPU_offscreen_height(ofs) != sizey))) {
		/* sizes differ, can't reuse */
		ofs = NULL;
	}

	const bool own_ofs = (ofs == NULL);
	DRW_opengl_context_enable();

	if (own_ofs) {
		/* bind */
		ofs = GPU_offscreen_create(sizex, sizey, use_full_sample ? 0 : samples, true, false, err_out);
		if (ofs == NULL) {
			DRW_opengl_context_disable();
			return NULL;
		}
	}

	GPU_offscreen_bind(ofs, true);

	/* read in pixels & stamp */
	ImBuf *ibuf = IMB_allocImBuf(sizex, sizey, 32, flag);

	/* render 3d view */
	if (rv3d->persp == RV3D_CAMOB && v3d->camera) {
		CameraParams params;
		Object *camera = BKE_camera_multiview_render(scene, v3d->camera, viewname);
		const Object *camera_eval = DEG_get_evaluated_object(
		                                depsgraph,
		                                camera);

		BKE_camera_params_init(&params);
		/* fallback for non camera objects */
		params.clipsta = v3d->near;
		params.clipend = v3d->far;
		BKE_camera_params_from_object(&params, camera_eval);
		BKE_camera_multiview_params(&scene->r, &params, camera_eval, viewname);
		BKE_camera_params_compute_viewplane(&params, sizex, sizey, scene->r.xasp, scene->r.yasp);
		BKE_camera_params_compute_matrix(&params);

		BKE_camera_to_gpu_dof(camera, &fx_settings);

		is_ortho = params.is_ortho;
		copy_m4_m4(winmat, params.winmat);
	}
	else {
		rctf viewplane;
		float clipsta, clipend;

		is_ortho = ED_view3d_viewplane_get(depsgraph, v3d, rv3d, sizex, sizey, &viewplane, &clipsta, &clipend, NULL);
		if (is_ortho) {
			orthographic_m4(winmat, viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, -clipend, clipend);
		}
		else {
			perspective_m4(winmat, viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, clipsta, clipend);
		}
	}

	if ((samples && use_full_sample) == 0) {
		/* Single-pass render, common case */
		ED_view3d_draw_offscreen(
		        depsgraph, scene, drawtype,
		        v3d, ar, sizex, sizey, NULL, winmat,
		        draw_sky, !is_ortho, viewname,
		        &fx_settings, ofs, NULL);

		if (ibuf->rect_float) {
			GPU_offscreen_read_pixels(ofs, GL_FLOAT, ibuf->rect_float);
		}
		else if (ibuf->rect) {
			GPU_offscreen_read_pixels(ofs, GL_UNSIGNED_BYTE, ibuf->rect);
		}
	}
	else {
		/* Multi-pass render, use accumulation buffer & jitter for 'full' oversampling.
		 * Use because OpenGL may use a lower quality MSAA, and only over-sample edges. */
		static float jit_ofs[32][2];
		float winmat_jitter[4][4];
		float *rect_temp = (ibuf->rect_float) ? ibuf->rect_float : MEM_mallocN(sizex * sizey * sizeof(float[4]), "rect_temp");
		float *accum_buffer = MEM_mallocN(sizex * sizey * sizeof(float[4]), "accum_buffer");
		GPUViewport *viewport = GPU_viewport_create_from_offscreen(ofs);

		BLI_jitter_init(jit_ofs, samples);

		/* first sample buffer, also initializes 'rv3d->persmat' */
		ED_view3d_draw_offscreen(
		        depsgraph, scene, drawtype,
		        v3d, ar, sizex, sizey, NULL, winmat,
		        draw_sky, !is_ortho, viewname,
		        &fx_settings, ofs, viewport);
		GPU_offscreen_read_pixels(ofs, GL_FLOAT, accum_buffer);

		/* skip the first sample */
		for (int j = 1; j < samples; j++) {
			copy_m4_m4(winmat_jitter, winmat);
			window_translate_m4(
			        winmat_jitter, rv3d->persmat,
			        (jit_ofs[j][0] * 2.0f) / sizex,
			        (jit_ofs[j][1] * 2.0f) / sizey);

			ED_view3d_draw_offscreen(
			        depsgraph, scene, drawtype,
			        v3d, ar, sizex, sizey, NULL, winmat_jitter,
			        draw_sky, !is_ortho, viewname,
			        &fx_settings, ofs, viewport);
			GPU_offscreen_read_pixels(ofs, GL_FLOAT, rect_temp);

			unsigned int i = sizex * sizey * 4;
			while (i--) {
				accum_buffer[i] += rect_temp[i];
			}
		}

		{
			/* don't free data owned by 'ofs' */
			GPU_viewport_clear_from_offscreen(viewport);
			GPU_viewport_free(viewport);
		}

		if (ibuf->rect_float == NULL) {
			MEM_freeN(rect_temp);
		}

		if (ibuf->rect_float) {
			float *rect_float = ibuf->rect_float;
			unsigned int i = sizex * sizey * 4;
			while (i--) {
				rect_float[i] = accum_buffer[i] / samples;
			}
		}
		else {
			unsigned char *rect_ub = (unsigned char *)ibuf->rect;
			unsigned int i = sizex * sizey * 4;
			while (i--) {
				rect_ub[i] = (unsigned char)(255.0f * accum_buffer[i] / samples);
			}
		}

		MEM_freeN(accum_buffer);
	}

	/* unbind */
	GPU_offscreen_unbind(ofs, true);

	if (own_ofs) {
		GPU_offscreen_free(ofs);
	}

	DRW_opengl_context_disable();

	if (ibuf->rect_float && ibuf->rect)
		IMB_rect_from_float(ibuf);

	return ibuf;
}

/**
 * Creates own fake 3d views (wrapping #ED_view3d_draw_offscreen_imbuf)
 *
 * \param ofs: Optional off-screen buffer can be NULL.
 * (avoids re-creating when doing multiple GL renders).
 *
 * \note used by the sequencer
 */
ImBuf *ED_view3d_draw_offscreen_imbuf_simple(
        Depsgraph *depsgraph, Scene *scene,
        int drawtype,
        Object *camera, int width, int height,
        unsigned int flag, unsigned int draw_flags,
        int alpha_mode, int samples, const char *viewname,
        GPUOffScreen *ofs, char err_out[256])
{
	View3D v3d = {NULL};
	ARegion ar = {NULL};
	RegionView3D rv3d = {{{0}}};

	/* connect data */
	v3d.regionbase.first = v3d.regionbase.last = &ar;
	ar.regiondata = &rv3d;
	ar.regiontype = RGN_TYPE_WINDOW;

	v3d.camera = camera;
	v3d.lay = scene->lay;
	v3d.drawtype = drawtype;
	v3d.flag2 = V3D_RENDER_OVERRIDE;

	if (draw_flags & V3D_OFSDRAW_USE_GPENCIL) {
		v3d.flag2 |= V3D_SHOW_GPENCIL;
	}
	if (draw_flags & V3D_OFSDRAW_USE_SOLID_TEX) {
		v3d.flag2 |= V3D_SOLID_TEX;
	}

	v3d.flag3 |= V3D_SHOW_WORLD;

	if (draw_flags & V3D_OFSDRAW_USE_CAMERA_DOF) {
		if (camera->type == OB_CAMERA) {
			v3d.fx_settings.dof = &((Camera *)camera->data)->gpu_dof;
			v3d.fx_settings.fx_flag |= GPU_FX_FLAG_DOF;
		}
	}

	rv3d.persp = RV3D_CAMOB;

	copy_m4_m4(rv3d.viewinv, v3d.camera->obmat);
	normalize_m4(rv3d.viewinv);
	invert_m4_m4(rv3d.viewmat, rv3d.viewinv);

	{
		CameraParams params;
		const Object *view_camera_eval = DEG_get_evaluated_object(
		                                     depsgraph,
		                                     BKE_camera_multiview_render(scene, v3d.camera, viewname));

		BKE_camera_params_init(&params);
		BKE_camera_params_from_object(&params, view_camera_eval);
		BKE_camera_multiview_params(&scene->r, &params, view_camera_eval, viewname);
		BKE_camera_params_compute_viewplane(&params, width, height, scene->r.xasp, scene->r.yasp);
		BKE_camera_params_compute_matrix(&params);

		copy_m4_m4(rv3d.winmat, params.winmat);
		v3d.near = params.clipsta;
		v3d.far = params.clipend;
		v3d.lens = params.lens;
	}

	mul_m4_m4m4(rv3d.persmat, rv3d.winmat, rv3d.viewmat);
	invert_m4_m4(rv3d.persinv, rv3d.viewinv);

	return ED_view3d_draw_offscreen_imbuf(
	        depsgraph, scene, drawtype,
	        &v3d, &ar, width, height, flag,
	        draw_flags, alpha_mode, samples, viewname, ofs, err_out);
}

/** \} */