Cycles: merge of cycles-x branch, a major update to the renderer

This includes much improved GPU rendering performance, viewport interactivity,
new shadow catcher, revamped sampling settings, subsurface scattering anisotropy,
new GPU volume sampling, improved PMJ sampling pattern, and more.

Some features have also been removed or changed, breaking backwards compatibility.
Including the removal of the OpenCL backend, for which alternatives are under
development.

Release notes and code docs:
https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycles
https://wiki.blender.org/wiki/Source/Render/Cycles

Credits:
* Sergey Sharybin
* Brecht Van Lommel
* Patrick Mours (OptiX backend)
* Christophe Hery (subsurface scattering anisotropy)
* William Leeson (PMJ sampling pattern)
* Alaska (various fixes and tweaks)
* Thomas Dinges (various fixes)

For the full commit history, see the cycles-x branch. This squashes together
all the changes since intermediate changes would often fail building or tests.

Ref T87839, T87837, T87836
Fixes T90734, T89353, T80267, T80267, T77185, T69800

1 files changed, 42 insertions, 4 deletions

diff --git a/source/blender/render/RE_engine.h b/source/blender/render/RE_engine.h
index dfc0d5d0e9f..2a3a5964262 100644
--- a/source/blender/render/RE_engine.h
+++ b/source/blender/render/RE_engine.h
@@ -40,6 +40,7 @@ struct RenderData;
 struct RenderEngine;
 struct RenderEngineType;
 struct RenderLayer;
+struct RenderPass;
 struct RenderResult;
 struct ReportList;
 struct Scene;
@@ -59,7 +60,7 @@ extern "C" {
 #define RE_USE_PREVIEW 4
 #define RE_USE_POSTPROCESS 8
 #define RE_USE_EEVEE_VIEWPORT 16
-#define RE_USE_SAVE_BUFFERS 32
+/* #define RE_USE_SAVE_BUFFERS_DEPRECATED 32 */
 #define RE_USE_SHADING_NODES_CUSTOM 64
 #define RE_USE_SPHERICAL_STEREO 128
 #define RE_USE_STEREO_VIEWPORT 256
@@ -75,6 +76,7 @@ extern "C" {
 #define RE_ENGINE_DO_UPDATE 8
 #define RE_ENGINE_RENDERING 16
 #define RE_ENGINE_HIGHLIGHT_TILES 32
+#define RE_ENGINE_CAN_DRAW 64
 
 extern ListBase R_engines;
 
@@ -87,7 +89,20 @@ typedef struct RenderEngineType {
   int flag;
 
   void (*update)(struct RenderEngine *engine, struct Main *bmain, struct Depsgraph *depsgraph);
+
   void (*render)(struct RenderEngine *engine, struct Depsgraph *depsgraph);
+
+  /* Offline rendering is finished - no more view layers will be rendered.
+   *
+   * All the pending data is to be communicated from the engine back to Blender. In a possibly
+   * most memory-efficient manner (engine might free its database before making Blender to allocate
+   * full-frame render result). */
+  void (*render_frame_finish)(struct RenderEngine *engine);
+
+  void (*draw)(struct RenderEngine *engine,
+               const struct bContext *context,
+               struct Depsgraph *depsgraph);
+
   void (*bake)(struct RenderEngine *engine,
                struct Depsgraph *depsgraph,
                struct Object *object,
@@ -132,9 +147,6 @@ typedef struct RenderEngine {
   struct Object *camera_override;
   unsigned int layer_override;
 
-  int tile_x;
-  int tile_y;
-
   struct Render *re;
   ListBase fullresult;
   char text[512]; /* IMA_MAX_RENDER_TEXT */
@@ -189,6 +201,10 @@ void RE_engine_end_result(RenderEngine *engine,
                           bool merge_results);
 struct RenderResult *RE_engine_get_result(struct RenderEngine *engine);
 
+struct RenderPass *RE_engine_pass_by_index_get(struct RenderEngine *engine,
+                                               const char *layer_name,
+                                               int index);
+
 const char *RE_engine_active_view_get(RenderEngine *engine);
 void RE_engine_active_view_set(RenderEngine *engine, const char *viewname);
 float RE_engine_get_camera_shift_x(RenderEngine *engine,
@@ -228,6 +244,24 @@ void RE_engine_register_pass(struct RenderEngine *engine,
 
 bool RE_engine_use_persistent_data(struct RenderEngine *engine);
 
+struct RenderEngine *RE_engine_get(const struct Render *re);
+
+/* Acquire render engine for drawing via its `draw()` callback.
+ *
+ * If drawing is not possible false is returned. If drawing is possible then the engine is
+ * "acquired" so that it can not be freed by the render pipeline.
+ *
+ * Drawing is possible if the engine has the `draw()` callback and it is in its `render()`
+ * callback. */
+bool RE_engine_draw_acquire(struct Render *re);
+void RE_engine_draw_release(struct Render *re);
+
+/* NOTE: Only used for Cycles's BLenderGPUDisplay integration with the draw manager. A subject
+ * for re-consideration. Do not use this functionality. */
+bool RE_engine_has_render_context(struct RenderEngine *engine);
+void RE_engine_render_context_enable(struct RenderEngine *engine);
+void RE_engine_render_context_disable(struct RenderEngine *engine);
+
 /* Engine Types */
 
 void RE_engines_init(void);
@@ -252,6 +286,10 @@ void RE_bake_engine_set_engine_parameters(struct Render *re,
 
 void RE_engine_free_blender_memory(struct RenderEngine *engine);
 
+void RE_engine_tile_highlight_set(
+    struct RenderEngine *engine, int x, int y, int width, int height, bool highlight);
+void RE_engine_tile_highlight_clear_all(struct RenderEngine *engine);
+
 #ifdef __cplusplus
 }
 #endif