Clay-Engine (merge clay-engine)

Initial work by Clément Foucault with contributions from Dalai Felinto
(mainly per-collection engine settings logic, and depsgraph iterator placeholder).

This makes Blender require OpenGL 3.3. Which means Intel graphic card
and OSX will break. Disable CLAY_ENGINE in CMake in those cases.

This is a prototype render engine intended to help the design of real
render engines. This is mainly an engine with enphasis in matcap and
ambient occlusion.

Implemented Features
--------------------

* Clay Render Engine, following the new API, to be used as reference for
future engines

* A more complete Matcap customization with more options

* Per-Collection render engine settings

* New Ground Truth AO - not enabled

Missing Features
----------------

* Finish object edit mode
  - Fix shaders to use new matrix
  - Fix artifacts when edge does off screen
  - Fix depth issue
  - Selection sillhouette
  - Mesh wires
  - Use mesh normals (for higher quality matcap)
  - Non-Mesh objects drawing
  - Widget drawing
  - Performance issues

* Finish mesh edit mode
  - Derived-Mesh-less edit mode API (mesh_rende.c)

* General edit mode
  - Per-collection edit mode settings

* General engines
  - Per-collection engine settings
    (they are their, but they still need to be flushed by depsgraph, and
    used by the drawing code)

3 files changed, 27 insertions, 4 deletions

diff --git a/source/blender/render/CMakeLists.txt b/source/blender/render/CMakeLists.txt
index 9e40ab02ee4..27fa119bc88 100644
--- a/source/blender/render/CMakeLists.txt
+++ b/source/blender/render/CMakeLists.txt
@@ -35,6 +35,7 @@ set(INC
 	../makesdna
 	../makesrna
 	../physics
+	../draw
 	../../../intern/guardedalloc
 	../../../intern/mikktspace
 	../../../intern/smoke/extern
diff --git a/source/blender/render/extern/include/RE_engine.h b/source/blender/render/extern/include/RE_engine.h
index f83a210275f..f1b3534b40a 100644
--- a/source/blender/render/extern/include/RE_engine.h
+++ b/source/blender/render/extern/include/RE_engine.h
@@ -39,6 +39,8 @@
 
 struct bNode;
 struct bNodeTree;
+struct CollectionEngineSettings;
+struct Main;
 struct Object;
 struct Render;
 struct RenderData;
@@ -63,6 +65,7 @@ struct BakePixel;
 #define RE_USE_TEXTURE_PREVIEW		128
 #define RE_USE_SHADING_NODES_CUSTOM 	256
 #define RE_USE_SPHERICAL_STEREO 512
+#define RE_USE_OGL_PIPELINE		1024
 
 /* RenderEngine.flag */
 #define RE_ENGINE_ANIMATION		1
@@ -97,6 +100,8 @@ typedef struct RenderEngineType {
 
 	void (*update_script_node)(struct RenderEngine *engine, struct bNodeTree *ntree, struct bNode *node);
 
+	void (*collection_settings_create)(struct RenderEngine *engine, struct CollectionEngineSettings *ces);
+
 	/* RNA integration */
 	ExtensionRNA ext;
 } RenderEngineType;
@@ -164,6 +169,7 @@ void RE_engine_frame_set(struct RenderEngine *engine, int frame, float subframe)
 
 void RE_engines_init(void);
 void RE_engines_exit(void);
+void RE_engines_register(struct Main *bmain, RenderEngineType *render_type);
 
 RenderEngineType *RE_engines_find(const char *idname);
 
diff --git a/source/blender/render/intern/source/external_engine.c b/source/blender/render/intern/source/external_engine.c
index fd9d95c63b6..1744d88a14f 100644
--- a/source/blender/render/intern/source/external_engine.c
+++ b/source/blender/render/intern/source/external_engine.c
@@ -45,6 +45,7 @@
 #include "BKE_camera.h"
 #include "BKE_global.h"
 #include "BKE_colortools.h"
+#include "BKE_layer.h"
 #include "BKE_report.h"
 #include "BKE_scene.h"
 
@@ -58,6 +59,8 @@
 #include "RE_pipeline.h"
 #include "RE_bake.h"
 
+#include "DRW_engine.h"
+
 #include "initrender.h"
 #include "renderpipeline.h"
 #include "render_types.h"
@@ -68,7 +71,7 @@
 static RenderEngineType internal_render_type = {
 	NULL, NULL,
 	"BLENDER_RENDER", N_("Blender Render"), RE_INTERNAL,
-	NULL, NULL, NULL, NULL, NULL, NULL,
+	NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 	{NULL, NULL, NULL}
 };
 
@@ -77,7 +80,7 @@ static RenderEngineType internal_render_type = {
 static RenderEngineType internal_game_type = {
 	NULL, NULL,
 	"BLENDER_GAME", N_("Blender Game"), RE_INTERNAL | RE_GAME,
-	NULL, NULL, NULL, NULL, NULL, NULL,
+	NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 	{NULL, NULL, NULL}
 };
 
@@ -87,16 +90,21 @@ ListBase R_engines = {NULL, NULL};
 
 void RE_engines_init(void)
 {
-	BLI_addtail(&R_engines, &internal_render_type);
+	RE_engines_register(NULL, &internal_render_type);
 #ifdef WITH_GAMEENGINE
-	BLI_addtail(&R_engines, &internal_game_type);
+	RE_engines_register(NULL, &internal_game_type);
 #endif
+	DRW_engines_init();
 }
 
 void RE_engines_exit(void)
 {
 	RenderEngineType *type, *next;
 
+	DRW_engines_free();
+
+	BKE_layer_collection_engine_settings_callback_free();
+
 	for (type = R_engines.first; type; type = next) {
 		next = type->next;
 
@@ -111,6 +119,14 @@ void RE_engines_exit(void)
 	}
 }
 
+void RE_engines_register(Main *bmain, RenderEngineType *render_type)
+{
+	if (render_type->collection_settings_create) {
+		BKE_layer_collection_engine_settings_callback_register(bmain, render_type->idname, render_type->collection_settings_create);
+	}
+	BLI_addtail(&R_engines, render_type);
+}
+
 RenderEngineType *RE_engines_find(const char *idname)
 {
 	RenderEngineType *type;