Refactor depsgraph/render logic to serve evaluated depsgraph to engines

User notes
----------
Compositing, rendering of multi-layers in Eevee should be fully working now.

Development notes
-----------------
Up until now we were still using the same depsgraph for rendering and viewport
evaluation. And we had to go out of our ways to be sure the depsgraphs were
updated.

Now we iterate over the (to be rendered) view layers and create a depsgraph to
each one, fully evaluated and call the render engines (Cycles, Eevee, ...) with
this viewlayer/depsgraph/evaluation context.

At this time we are not handling data persistency, Depsgraph is created from
scratch prior to rendering each frame.  So I got rid of most of the partial
update calls we had during the render pipeline.

Cycles: Brecht Van Lommel did a patch to tackle some of the required Cycles
changes but this commit mark these changes as TODOs. Basically Cycles needs to
render one layer at a time.

Reviewers: sergey, brecht

Differential Revision: https://developer.blender.org/D3073

1 files changed, 28 insertions, 13 deletions

diff --git a/source/blender/editors/object/object_bake_api.c b/source/blender/editors/object/object_bake_api.c
index c8bcc9224e9..acf3f73c9c6 100644
--- a/source/blender/editors/object/object_bake_api.c
+++ b/source/blender/editors/object/object_bake_api.c
@@ -56,9 +56,11 @@
 #include "BKE_report.h"
 #include "BKE_modifier.h"
 #include "BKE_mesh.h"
+#include "BKE_scene.h"
 #include "BKE_screen.h"
 
 #include "DEG_depsgraph.h"
+#include "DEG_depsgraph_build.h"
 
 #include "RE_engine.h"
 #include "RE_pipeline.h"
@@ -84,8 +86,8 @@ static void bake_set_props(wmOperator *op, Scene *scene);
 typedef struct BakeAPIRender {
 	Object *ob;
 	Main *main;
-	Depsgraph *depsgraph;
 	Scene *scene;
+	ViewLayer *view_layer;
 	ReportList *reports;
 	ListBase selected_objects;
 
@@ -634,7 +636,8 @@ static Mesh *bake_mesh_new_from_object(EvaluationContext *eval_ctx, Main *bmain,
 }
 
 static int bake(
-        Render *re, Main *bmain, Depsgraph *graph, Scene *scene, Object *ob_low, ListBase *selected_objects, ReportList *reports,
+        Render *re, Main *bmain, Scene *scene, ViewLayer *view_layer, Object *ob_low, ListBase *selected_objects,
+        ReportList *reports,
         const eScenePassType pass_type, const int pass_filter, const int margin,
         const eBakeSaveMode save_mode, const bool is_clear, const bool is_split_materials,
         const bool is_automatic_name, const bool is_selected_to_active, const bool is_cage,
@@ -642,6 +645,10 @@ static int bake(
         const char *custom_cage, const char *filepath, const int width, const int height,
         const char *identifier, ScrArea *sa, const char *uv_layer)
 {
+	EvaluationContext *eval_ctx = DEG_evaluation_context_new(DAG_EVAL_RENDER);
+	Depsgraph *depsgraph = DEG_graph_new();
+	DEG_evaluation_context_init_from_view_layer_for_render(eval_ctx, depsgraph, scene, view_layer);
+
 	int op_result = OPERATOR_CANCELLED;
 	bool ok = false;
 
@@ -673,7 +680,7 @@ static int bake(
 	size_t num_pixels;
 	int tot_materials;
 
-	RE_bake_engine_set_engine_parameters(re, bmain, graph, scene);
+	RE_bake_engine_set_engine_parameters(re, bmain, scene);
 
 	if (!RE_bake_has_engine(re)) {
 		BKE_report(reports, RPT_ERROR, "Current render engine does not support baking");
@@ -783,8 +790,16 @@ static int bake(
 		}
 	}
 
+	/* Make sure depsgraph is up to date. */
+	DEG_graph_build_from_view_layer(depsgraph, bmain, scene, view_layer);
+	BKE_scene_graph_update_tagged(eval_ctx,
+	                              depsgraph,
+	                              bmain,
+	                              scene,
+	                              view_layer);
+
 	/* get the mesh as it arrives in the renderer */
-	me_low = bake_mesh_new_from_object(RE_GetEvalCtx(re), bmain, scene, ob_low);
+	me_low = bake_mesh_new_from_object(eval_ctx, bmain, scene, ob_low);
 
 	/* populate the pixel array with the face data */
 	if ((is_selected_to_active && (ob_cage == NULL) && is_cage) == false)
@@ -799,7 +814,7 @@ static int bake(
 
 		/* prepare cage mesh */
 		if (ob_cage) {
-			me_cage = bake_mesh_new_from_object(RE_GetEvalCtx(re), bmain, scene, ob_cage);
+			me_cage = bake_mesh_new_from_object(eval_ctx, bmain, scene, ob_cage);
 			if ((me_low->totpoly != me_cage->totpoly) || (me_low->totloop != me_cage->totloop)) {
 				BKE_report(reports, RPT_ERROR,
 				           "Invalid cage object, the cage mesh must have the same number "
@@ -831,7 +846,7 @@ static int bake(
 			ob_low->modifiers = modifiers_tmp;
 
 			/* get the cage mesh as it arrives in the renderer */
-			me_cage = bake_mesh_new_from_object(RE_GetEvalCtx(re), bmain, scene, ob_low);
+			me_cage = bake_mesh_new_from_object(eval_ctx, bmain, scene, ob_low);
 			RE_bake_pixels_populate(me_cage, pixel_array_low, num_pixels, &bake_images, uv_layer);
 		}
 
@@ -857,7 +872,7 @@ static int bake(
 			tmd->quad_method = MOD_TRIANGULATE_QUAD_FIXED;
 			tmd->ngon_method = MOD_TRIANGULATE_NGON_EARCLIP;
 
-			highpoly[i].me = bake_mesh_new_from_object(RE_GetEvalCtx(re), bmain, scene, highpoly[i].ob);
+			highpoly[i].me = bake_mesh_new_from_object(eval_ctx, bmain, scene, highpoly[i].ob);
 			highpoly[i].ob->restrictflag &= ~OB_RESTRICT_RENDER;
 
 			/* lowpoly to highpoly transformation matrix */
@@ -960,7 +975,7 @@ cage_cleanup:
 						md->mode &= ~eModifierMode_Render;
 					}
 
-					me_nores = bake_mesh_new_from_object(RE_GetEvalCtx(re), bmain, scene, ob_low);
+					me_nores = bake_mesh_new_from_object(eval_ctx, bmain, scene, ob_low);
 					RE_bake_pixels_populate(me_nores, pixel_array_low, num_pixels, &bake_images, uv_layer);
 
 					RE_bake_normal_world_to_tangent(pixel_array_low, num_pixels, depth, result, me_nores, normal_swizzle, ob_low->obmat);
@@ -1121,7 +1136,7 @@ static void bake_init_api_data(wmOperator *op, bContext *C, BakeAPIRender *bkr)
 
 	bkr->ob = CTX_data_active_object(C);
 	bkr->main = CTX_data_main(C);
-	bkr->depsgraph = CTX_data_depsgraph(C);
+	bkr->view_layer = CTX_data_view_layer(C);
 	bkr->scene = CTX_data_scene(C);
 	bkr->sa = sc ? BKE_screen_find_big_area(sc, SPACE_IMAGE, 10) : NULL;
 
@@ -1205,7 +1220,7 @@ static int bake_exec(bContext *C, wmOperator *op)
 
 	if (bkr.is_selected_to_active) {
 		result = bake(
-		        bkr.render, bkr.main, bkr.depsgraph, bkr.scene, bkr.ob, &bkr.selected_objects, bkr.reports,
+		        bkr.render, bkr.main, bkr.scene, bkr.view_layer, bkr.ob, &bkr.selected_objects, bkr.reports,
 		        bkr.pass_type, bkr.pass_filter, bkr.margin, bkr.save_mode,
 		        bkr.is_clear, bkr.is_split_materials, bkr.is_automatic_name, true, bkr.is_cage,
 		        bkr.cage_extrusion, bkr.normal_space, bkr.normal_swizzle,
@@ -1218,7 +1233,7 @@ static int bake_exec(bContext *C, wmOperator *op)
 		for (link = bkr.selected_objects.first; link; link = link->next) {
 			Object *ob_iter = link->ptr.data;
 			result = bake(
-			        bkr.render, bkr.main, bkr.depsgraph, bkr.scene, ob_iter, NULL, bkr.reports,
+			        bkr.render, bkr.main, bkr.scene, bkr.view_layer, ob_iter, NULL, bkr.reports,
 			        bkr.pass_type, bkr.pass_filter, bkr.margin, bkr.save_mode,
 			        is_clear, bkr.is_split_materials, bkr.is_automatic_name, false, bkr.is_cage,
 			        bkr.cage_extrusion, bkr.normal_space, bkr.normal_swizzle,
@@ -1263,7 +1278,7 @@ static void bake_startjob(void *bkv, short *UNUSED(stop), short *do_update, floa
 
 	if (bkr->is_selected_to_active) {
 		bkr->result = bake(
-		        bkr->render, bkr->main, bkr->depsgraph, bkr->scene, bkr->ob, &bkr->selected_objects, bkr->reports,
+		        bkr->render, bkr->main, bkr->scene, bkr->view_layer, bkr->ob, &bkr->selected_objects, bkr->reports,
 		        bkr->pass_type, bkr->pass_filter, bkr->margin, bkr->save_mode,
 		        bkr->is_clear, bkr->is_split_materials, bkr->is_automatic_name, true, bkr->is_cage,
 		        bkr->cage_extrusion, bkr->normal_space, bkr->normal_swizzle,
@@ -1276,7 +1291,7 @@ static void bake_startjob(void *bkv, short *UNUSED(stop), short *do_update, floa
 		for (link = bkr->selected_objects.first; link; link = link->next) {
 			Object *ob_iter = link->ptr.data;
 			bkr->result = bake(
-			        bkr->render, bkr->main, bkr->depsgraph, bkr->scene, ob_iter, NULL, bkr->reports,
+			        bkr->render, bkr->main, bkr->scene, bkr->view_layer, ob_iter, NULL, bkr->reports,
 			        bkr->pass_type, bkr->pass_filter, bkr->margin, bkr->save_mode,
 			        is_clear, bkr->is_split_materials, bkr->is_automatic_name, false, bkr->is_cage,
 			        bkr->cage_extrusion, bkr->normal_space, bkr->normal_swizzle,