DRW / Render: Add support for render pipeline in drawmanager.

For simplicity we choose to execute the rendering of Opengl engines in the main thread and block the interface.
This might be addressed in the future at least for video rendering.

A drawmanager wrapper (DRW_render_to_image) is called by the render pipeline to set up the Opengl state and then call the specific draw_engine->render_to_image function.

23 files changed, 129 insertions, 12 deletions

diff --git a/source/blender/draw/DRW_engine.h b/source/blender/draw/DRW_engine.h
index 0cfa1fe7d6a..c4946e2a4b8 100644
--- a/source/blender/draw/DRW_engine.h
+++ b/source/blender/draw/DRW_engine.h
@@ -46,6 +46,7 @@ struct View3D;
 struct rcti;
 struct GPUOffScreen;
 struct GPUViewport;
+struct RenderEngine;
 struct RenderEngineType;
 struct WorkSpace;
 
@@ -67,6 +68,7 @@ typedef struct DefaultTextureList {
 void DRW_engines_register(void);
 void DRW_engines_free(void);
 
+bool DRW_engine_render_support(struct DrawEngineType *draw_engine_type);
 void DRW_engine_register(struct DrawEngineType *draw_engine_type);
 void DRW_engine_viewport_data_size_get(
         const void *engine_type,
diff --git a/source/blender/draw/engines/basic/basic_engine.c b/source/blender/draw/engines/basic/basic_engine.c
index 10dfe7b5996..31a431e3001 100644
--- a/source/blender/draw/engines/basic/basic_engine.c
+++ b/source/blender/draw/engines/basic/basic_engine.c
@@ -264,6 +264,7 @@ DrawEngineType draw_engine_basic_type = {
 	&basic_draw_scene,
 	NULL,
 	NULL,
+	NULL,
 };
 
 /* Note: currently unused, we may want to register so we can see this when debugging the view. */
diff --git a/source/blender/draw/engines/clay/clay_engine.c b/source/blender/draw/engines/clay/clay_engine.c
index a9a919f7ac2..d2bf164efdc 100644
--- a/source/blender/draw/engines/clay/clay_engine.c
+++ b/source/blender/draw/engines/clay/clay_engine.c
@@ -949,6 +949,7 @@ DrawEngineType draw_engine_clay_type = {
 	&clay_draw_scene,
 	NULL,
 	NULL,
+	NULL,
 };
 
 RenderEngineType DRW_engine_viewport_clay_type = {
diff --git a/source/blender/draw/engines/external/external_engine.c b/source/blender/draw/engines/external/external_engine.c
index 851d0ef9eb7..ec0141953fe 100644
--- a/source/blender/draw/engines/external/external_engine.c
+++ b/source/blender/draw/engines/external/external_engine.c
@@ -218,6 +218,7 @@ DrawEngineType draw_engine_external_type = {
 	&external_draw_scene,
 	NULL,
 	NULL,
+	NULL,
 };
 
 /* Note: currently unused, we should not register unless we want to see this when debugging the view. */
diff --git a/source/blender/draw/intern/DRW_render.h b/source/blender/draw/intern/DRW_render.h
index f5943f2130b..a9ab2d2cf0e 100644
--- a/source/blender/draw/intern/DRW_render.h
+++ b/source/blender/draw/intern/DRW_render.h
@@ -139,6 +139,8 @@ typedef struct DrawEngineType {
 
 	void (*view_update)(void *vedata);
 	void (*id_update)(void *vedata, struct ID *id);
+
+	void (*render_to_image)(void *vedata, struct RenderEngine *engine, struct Depsgraph *graph);
 } DrawEngineType;
 
 #ifndef __DRW_ENGINE_H__
@@ -386,6 +388,11 @@ struct DefaultTextureList     *DRW_viewport_texture_list_get(void);
 
 void DRW_viewport_request_redraw(void);
 
+void DRW_render_to_image(struct RenderEngine *re, struct Depsgraph *depsgraph);
+void DRW_render_object_iter(
+	void *vedata, struct RenderEngine *engine, struct Depsgraph *graph,
+	void (*callback)(void *vedata, struct Object *ob, struct RenderEngine *engine, struct Depsgraph *graph));
+
 /* ViewLayers */
 void *DRW_view_layer_engine_data_get(DrawEngineType *engine_type);
 void **DRW_view_layer_engine_data_ensure(DrawEngineType *engine_type, void (*callback)(void *storage));
diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 70b246047a9..a882c89ff88 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -2365,7 +2365,9 @@ void DRW_framebuffer_init(
 			}
 		}
 
-		GPU_framebuffer_bind(DST.default_framebuffer);
+		if (DST.default_framebuffer != NULL) {
+			GPU_framebuffer_bind(DST.default_framebuffer);
+		}
 	}
 }
 
@@ -2626,14 +2628,17 @@ static void drw_viewport_var_init(void)
 		DST.default_framebuffer = NULL;
 		DST.vmempool = NULL;
 	}
-	/* Refresh DST.screenvecs */
-	copy_v3_v3(DST.screenvecs[0], rv3d->viewinv[0]);
-	copy_v3_v3(DST.screenvecs[1], rv3d->viewinv[1]);
-	normalize_v3(DST.screenvecs[0]);
-	normalize_v3(DST.screenvecs[1]);
 
-	/* Refresh DST.pixelsize */
-	DST.pixsize = rv3d->pixsize;
+	if (rv3d != NULL) {
+		/* Refresh DST.screenvecs */
+		copy_v3_v3(DST.screenvecs[0], rv3d->viewinv[0]);
+		copy_v3_v3(DST.screenvecs[1], rv3d->viewinv[1]);
+		normalize_v3(DST.screenvecs[0]);
+		normalize_v3(DST.screenvecs[1]);
+
+		/* Refresh DST.pixelsize */
+		DST.pixsize = rv3d->pixsize;
+	}
 
 	/* Reset facing */
 	DST.frontface = GL_CCW;
@@ -2664,6 +2669,7 @@ void DRW_viewport_matrix_get(float mat[4][4], DRWViewportMatrixType type)
 		copy_m4_m4(mat, viewport_matrix_override.mat[type]);
 	}
 	else {
+		BLI_assert(rv3d != NULL); /* Can't use this in render mode. */
 		switch (type) {
 			case DRW_MAT_PERS:
 				copy_m4_m4(mat, rv3d->persmat);
@@ -2704,6 +2710,7 @@ void DRW_viewport_matrix_override_unset(DRWViewportMatrixType type)
 bool DRW_viewport_is_persp_get(void)
 {
 	RegionView3D *rv3d = DST.draw_ctx.rv3d;
+	BLI_assert(rv3d);
 	return rv3d->is_persp;
 }
 
@@ -3422,9 +3429,7 @@ void DRW_draw_render_loop_ex(
 	/* Init engines */
 	drw_engines_init();
 
-	/* TODO : tag to refresh by the dependency graph */
-	/* ideally only refresh when objects are added/removed */
-	/* or render properties / materials change */
+	/* Cache filling */
 	{
 		PROFILE_START(stime);
 		drw_engines_cache_init();
@@ -3569,6 +3574,70 @@ void DRW_draw_render_loop_offscreen(
 	GPU_offscreen_bind(ofs, false);
 }
 
+void DRW_render_to_image(RenderEngine *re, struct Depsgraph *depsgraph)
+{
+	Scene *scene = DEG_get_evaluated_scene(depsgraph);
+	ViewLayer *view_layer = DEG_get_evaluated_view_layer(depsgraph);
+	RenderEngineType *engine_type = re->type;
+	DrawEngineType *draw_engine_type = engine_type->draw_engine;
+	RenderData *r = &scene->r;
+
+	/* Reset before using it. */
+	memset(&DST, 0x0, sizeof(DST));
+	DST.options.is_image_render = true;
+
+	DST.draw_ctx = (DRWContextState){
+	    NULL, NULL, NULL, scene, view_layer, OBACT(view_layer), engine_type, depsgraph, NULL
+	};
+
+	DST.viewport = GPU_viewport_create();
+	const int size[2] = {(r->size * r->xsch) / 100, (r->size * r->ysch) / 100};
+	GPU_viewport_size_set(DST.viewport, size);
+
+	drw_viewport_var_init();
+
+	ViewportEngineData *data = DRW_viewport_engine_data_ensure(draw_engine_type);
+
+	/* set default viewport */
+	gpuPushAttrib(GPU_ENABLE_BIT | GPU_VIEWPORT_BIT);
+	glDisable(GL_SCISSOR_TEST);
+	glViewport(0, 0, size[0], size[1]);
+
+	engine_type->draw_engine->render_to_image(data, re, depsgraph);
+
+	/* TODO grease pencil */
+
+	GPU_viewport_free(DST.viewport);
+	MEM_freeN(DST.viewport);
+
+	DRW_state_reset();
+	/* FIXME GL_DEPTH_TEST is enabled by default but it seems
+	 * to trigger some bad behaviour / artifacts if it's turned
+	 * on at this point. */
+	glDisable(GL_DEPTH_TEST);
+
+	/* Restore Drawing area. */
+	gpuPopAttrib();
+	glEnable(GL_SCISSOR_TEST);
+	GPU_framebuffer_restore();
+
+#ifdef DEBUG
+	/* Avoid accidental reuse. */
+	memset(&DST, 0xFF, sizeof(DST));
+#endif
+}
+
+void DRW_render_object_iter(
+	void *vedata, RenderEngine *engine, struct Depsgraph *depsgraph,
+	void (*callback)(void *vedata, Object *ob, RenderEngine *engine, struct Depsgraph *depsgraph))
+{
+	DEG_OBJECT_ITER_FOR_RENDER_ENGINE(depsgraph, ob, DRW_iterator_mode_get())
+	{
+		callback(vedata, ob, engine, depsgraph);
+	}
+	DEG_OBJECT_ITER_FOR_RENDER_ENGINE_END
+}
+
 /**
  * object mode select-loop, see: ED_view3d_draw_select_loop (legacy drawing).
  */
@@ -3796,7 +3865,7 @@ void DRW_state_dfdy_factors_get(float dfdyfac[2])
  */
 bool DRW_state_is_fbo(void)
 {
-	return (DST.default_framebuffer != NULL);
+	return ((DST.default_framebuffer != NULL) || DST.options.is_image_render);
 }
 
 /**
@@ -3894,6 +3963,11 @@ const DRWContextState *DRW_context_state_get(void)
 /** \name Init/Exit (DRW_engines)
  * \{ */
 
+bool DRW_engine_render_support(DrawEngineType *draw_engine_type)
+{
+	return draw_engine_type->render_to_image;
+}
+
 void DRW_engine_register(DrawEngineType *draw_engine_type)
 {
 	BLI_addtail(&DRW_engines, draw_engine_type);
diff --git a/source/blender/draw/modes/edit_armature_mode.c b/source/blender/draw/modes/edit_armature_mode.c
index 4deb4f86692..3c0c33b1daa 100644
--- a/source/blender/draw/modes/edit_armature_mode.c
+++ b/source/blender/draw/modes/edit_armature_mode.c
@@ -154,4 +154,5 @@ DrawEngineType draw_engine_edit_armature_type = {
 	NULL,
 	&EDIT_ARMATURE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/edit_curve_mode.c b/source/blender/draw/modes/edit_curve_mode.c
index ec12f7570c2..54a1bd79572 100644
--- a/source/blender/draw/modes/edit_curve_mode.c
+++ b/source/blender/draw/modes/edit_curve_mode.c
@@ -347,4 +347,5 @@ DrawEngineType draw_engine_edit_curve_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&EDIT_CURVE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/edit_lattice_mode.c b/source/blender/draw/modes/edit_lattice_mode.c
index ff4c557326e..e676677ff97 100644
--- a/source/blender/draw/modes/edit_lattice_mode.c
+++ b/source/blender/draw/modes/edit_lattice_mode.c
@@ -294,4 +294,5 @@ DrawEngineType draw_engine_edit_lattice_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&EDIT_LATTICE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/edit_mesh_mode.c b/source/blender/draw/modes/edit_mesh_mode.c
index 1a8c03e3933..29ba658f79d 100644
--- a/source/blender/draw/modes/edit_mesh_mode.c
+++ b/source/blender/draw/modes/edit_mesh_mode.c
@@ -610,4 +610,5 @@ DrawEngineType draw_engine_edit_mesh_type = {
 	NULL,
 	&EDIT_MESH_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/edit_metaball_mode.c b/source/blender/draw/modes/edit_metaball_mode.c
index a83f5ae33bc..78ceaf8b6f1 100644
--- a/source/blender/draw/modes/edit_metaball_mode.c
+++ b/source/blender/draw/modes/edit_metaball_mode.c
@@ -248,4 +248,5 @@ DrawEngineType draw_engine_edit_metaball_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&EDIT_METABALL_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/edit_surface_mode.c b/source/blender/draw/modes/edit_surface_mode.c
index 4e60c4abff5..8f0371925db 100644
--- a/source/blender/draw/modes/edit_surface_mode.c
+++ b/source/blender/draw/modes/edit_surface_mode.c
@@ -266,4 +266,5 @@ DrawEngineType draw_engine_edit_surface_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&EDIT_SURFACE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/edit_text_mode.c b/source/blender/draw/modes/edit_text_mode.c
index b375bad84b5..60f28d89f4b 100644
--- a/source/blender/draw/modes/edit_text_mode.c
+++ b/source/blender/draw/modes/edit_text_mode.c
@@ -309,4 +309,5 @@ DrawEngineType draw_engine_edit_text_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&EDIT_TEXT_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/object_mode.c b/source/blender/draw/modes/object_mode.c
index 4aa0d4141e4..f27f41c3d2a 100644
--- a/source/blender/draw/modes/object_mode.c
+++ b/source/blender/draw/modes/object_mode.c
@@ -2044,4 +2044,5 @@ DrawEngineType draw_engine_object_type = {
 	NULL,
 	&OBJECT_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/paint_texture_mode.c b/source/blender/draw/modes/paint_texture_mode.c
index b49da0cba2f..2a5eabd08fa 100644
--- a/source/blender/draw/modes/paint_texture_mode.c
+++ b/source/blender/draw/modes/paint_texture_mode.c
@@ -414,4 +414,5 @@ DrawEngineType draw_engine_paint_texture_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&PAINT_TEXTURE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/paint_vertex_mode.c b/source/blender/draw/modes/paint_vertex_mode.c
index e430fca5742..835fefdee26 100644
--- a/source/blender/draw/modes/paint_vertex_mode.c
+++ b/source/blender/draw/modes/paint_vertex_mode.c
@@ -213,4 +213,5 @@ DrawEngineType draw_engine_paint_vertex_type = {
 	NULL,
 	&PAINT_VERTEX_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/paint_weight_mode.c b/source/blender/draw/modes/paint_weight_mode.c
index e139b4af97f..3cc2ad63ed4 100644
--- a/source/blender/draw/modes/paint_weight_mode.c
+++ b/source/blender/draw/modes/paint_weight_mode.c
@@ -251,4 +251,5 @@ DrawEngineType draw_engine_paint_weight_type = {
 	NULL,
 	&PAINT_WEIGHT_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/particle_mode.c b/source/blender/draw/modes/particle_mode.c
index 6a3e53a72c2..0d0758971d5 100644
--- a/source/blender/draw/modes/particle_mode.c
+++ b/source/blender/draw/modes/particle_mode.c
@@ -261,4 +261,5 @@ DrawEngineType draw_engine_particle_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&PARTICLE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/pose_mode.c b/source/blender/draw/modes/pose_mode.c
index 1c2acd56085..560773f2d05 100644
--- a/source/blender/draw/modes/pose_mode.c
+++ b/source/blender/draw/modes/pose_mode.c
@@ -195,4 +195,5 @@ DrawEngineType draw_engine_pose_type = {
 	NULL,
 	&POSE_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/draw/modes/sculpt_mode.c b/source/blender/draw/modes/sculpt_mode.c
index d9f1f5ebe91..d8c5bae522b 100644
--- a/source/blender/draw/modes/sculpt_mode.c
+++ b/source/blender/draw/modes/sculpt_mode.c
@@ -302,4 +302,5 @@ DrawEngineType draw_engine_sculpt_type = {
 	NULL, /* draw_background but not needed by mode engines */
 	&SCULPT_draw_scene,
 	NULL,
+	NULL,
 };
diff --git a/source/blender/editors/render/render_internal.c b/source/blender/editors/render/render_internal.c
index 80bdeaa8069..233365ec926 100644
--- a/source/blender/editors/render/render_internal.c
+++ b/source/blender/editors/render/render_internal.c
@@ -844,6 +844,7 @@ static int screen_render_invoke(bContext *C, wmOperator *op, const wmEvent *even
 	Main *mainp;
 	ViewLayer *view_layer = NULL;
 	Scene *scene = CTX_data_scene(C);
+	RenderEngineType *re_type = RE_engines_find(scene->view_render.engine_id);
 	Render *re;
 	wmJob *wm_job;
 	RenderJob *rj;
@@ -856,6 +857,13 @@ static int screen_render_invoke(bContext *C, wmOperator *op, const wmEvent *even
 	struct Object *camera_override = v3d ? V3D_CAMERA_LOCAL(v3d) : NULL;
 	const char *name;
 	ScrArea *sa;
+
+	/* XXX FIXME If engine is an OpenGL engine do not run modal.
+	 * This is a problem for animation rendering since you cannot abort them.
+	 * This also does not open an image editor space. */
+	if (RE_engine_is_opengl(re_type)) {
+		return screen_render_exec(C, op);
+	}
 	
 	/* only one render job at a time */
 	if (WM_jobs_test(CTX_wm_manager(C), scene, WM_JOB_TYPE_RENDER))
diff --git a/source/blender/render/extern/include/RE_engine.h b/source/blender/render/extern/include/RE_engine.h
index 60ffd8f42e4..f789ab702fe 100644
--- a/source/blender/render/extern/include/RE_engine.h
+++ b/source/blender/render/extern/include/RE_engine.h
@@ -183,6 +183,8 @@ void RE_engines_init(void);
 void RE_engines_exit(void);
 void RE_engines_register(struct Main *bmain, RenderEngineType *render_type);
 
+bool RE_engine_is_opengl(RenderEngineType *render_type);
+
 RenderEngineType *RE_engines_find(const char *idname);
 
 rcti* RE_engine_get_current_tiles(struct Render *re, int *r_total_tiles, bool *r_needs_free);
diff --git a/source/blender/render/intern/source/external_engine.c b/source/blender/render/intern/source/external_engine.c
index 68077d4d93b..2714e8b7685 100644
--- a/source/blender/render/intern/source/external_engine.c
+++ b/source/blender/render/intern/source/external_engine.c
@@ -155,6 +155,13 @@ bool RE_engine_is_external(Render *re)
 	return (re->engine && re->engine->type && re->engine->type->render_to_image);
 }
 
+bool RE_engine_is_opengl(RenderEngineType *render_type)
+{
+	/* TODO refine? Can we have ogl render engine without ogl render pipeline? */
+	return (render_type->draw_engine != NULL) &&
+	       DRW_engine_render_support(render_type->draw_engine);
+}
+
 /* Create, Free */
 
 RenderEngine *RE_engine_create(RenderEngineType *type)