OpenSubdiv: Commit of OpenSubdiv integration into Blender

This commit contains all the remained parts needed for initial integration of
OpenSubdiv into Blender's subdivision surface code. Includes both GPU and CPU
backends which works in the following way:

- When SubSurf modifier is the last in the modifiers stack then GPU pipeline
  of OpenSubdiv is used, making viewport performance as fast as possible.

  This also requires graphscard with GLSL 1.5 support. If this requirement is
  not met, then no GPU pipeline is used at all.

- If SubSurf is not a last modifier or if DerivesMesh is being evaluated for
  rendering then CPU limit evaluation API from OpenSubdiv is used. This only
  replaces the legacy evaluation code from CCGSubSurf_legacy, but keeps CCG
  structures exactly the same as they used to be for ages now.

This integration is fully covered with ifdef and not enabled by default
because there are several TODOs to be solved first:

- Face varying data interpolation is not really cleanly implemented for GPU
  in OpenSubdiv 3.0. It is also not implemented for limit evaluation API.

  This basically means we'll have really hard time supporting UVs.

- Limit evaluation only works with adaptivly subdivided meshes so far, which
  basically means all the points of CCG are pushed to the limit. This gives
  different result from old code.

- There are some serious optimizations possible on the topology refiner
  creation, which would speed up initial OpenSubdiv mesh creation.

- There are some hardcoded asumptions in the GPU and DerivedMesh areas which
  could be generalized.

  That's something where Antony and Campbell can help, making it so the code
  is structured in a way which is reusable by all planned viewport projects.

- There are also some workarounds in the dependency graph to make sure OpenGL
  buffers are only freed from the main thread.

Those who'll be wanting to make experiments with this code should grab dev
branch (NOT master) from

  https://github.com/Nazg-Gul/OpenSubdiv/tree/dev

There are some patches applied in there which we're working on on getting
into upstream.

4 files changed, 90 insertions, 0 deletions

diff --git a/source/blender/makesrna/SConscript b/source/blender/makesrna/SConscript
index f8eb2e1807c..52c01f6d476 100644
--- a/source/blender/makesrna/SConscript
+++ b/source/blender/makesrna/SConscript
@@ -139,6 +139,10 @@ if env['WITH_BF_FREESTYLE']:
     defs.append('WITH_FREESTYLE')
     incs += ' ../freestyle'
 
+if env['WITH_BF_OPENSUBDIV']:
+    incs += ' #/intern/opensubdiv'
+    defs.append('WITH_OPENSUBDIV')
+
 if env['OURPLATFORM'] == 'linux':
     cflags='-pthread'
 
diff --git a/source/blender/makesrna/intern/CMakeLists.txt b/source/blender/makesrna/intern/CMakeLists.txt
index e878e0877d2..bef2fa3084e 100644
--- a/source/blender/makesrna/intern/CMakeLists.txt
+++ b/source/blender/makesrna/intern/CMakeLists.txt
@@ -300,6 +300,13 @@ if(WITH_FREESTYLE)
 	add_definitions(-DWITH_FREESTYLE)
 endif()
 
+if(WITH_OPENSUBDIV)
+	list(APPEND INC
+		../../../../intern/opensubdiv
+	)
+	add_definitions(-DWITH_OPENSUBDIV)
+endif()
+
 # Build makesrna executable
 blender_include_dirs(
 	.
diff --git a/source/blender/makesrna/intern/SConscript b/source/blender/makesrna/intern/SConscript
index afa4ab3a67d..0e36a4c9712 100644
--- a/source/blender/makesrna/intern/SConscript
+++ b/source/blender/makesrna/intern/SConscript
@@ -154,6 +154,10 @@ if env['WITH_BF_FREESTYLE']:
     defs.append('WITH_FREESTYLE')
     incs += ' ../../freestyle'
 
+if env['WITH_BF_OPENSUBDIV']:
+    defs.append('WITH_OPENSUBDIV')
+    incs += ' #intern/opensubdiv'
+
 if env['OURPLATFORM'] == 'linux':
     cflags='-pthread'
 
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index cf327583d47..b2af13aa106 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -61,6 +61,19 @@ static EnumPropertyItem compute_device_type_items[] = {
 };
 #endif
 
+#ifdef WITH_OPENSUBDIV
+static EnumPropertyItem opensubdiv_compute_type_items[] = {
+	{USER_OPENSUBDIV_COMPUTE_NONE, "NONE", 0, "None", ""},
+	{USER_OPENSUBDIV_COMPUTE_CPU, "CPU", 0, "CPU", ""},
+	{USER_OPENSUBDIV_COMPUTE_OPENMP, "OPENMP", 0, "OpenMP", ""},
+	{USER_OPENSUBDIV_COMPUTE_OPENCL, "OPENCL", 0, "OpenCL", ""},
+	{USER_OPENSUBDIV_COMPUTE_CUDA, "CUDA", 0, "CUDA", ""},
+	{USER_OPENSUBDIV_COMPUTE_GLSL_TRANSFORM_FEEDBACK, "GLSL_TRANSFORM_FEEDBACL", 0, "GLSL Transform Feedback", ""},
+	{USER_OPENSUBDIV_COMPUTE_GLSL_COMPUTE, "GLSL_COMPUTE", 0, "GLSL Compute", ""},
+	{ 0, NULL, 0, NULL, NULL}
+};
+#endif
+
 static EnumPropertyItem audio_device_items[] = {
 	{0, "NONE", 0, "None", "Null device - there will be no audio output"},
 #ifdef WITH_SDL
@@ -106,6 +119,10 @@ EnumPropertyItem navigation_mode_items[] = {
 
 #include "CCL_api.h"
 
+#ifdef WITH_OPENSUBDIV
+#  include "opensubdiv_capi.h"
+#endif
+
 #ifdef WITH_SDL_DYNLOAD
 #  include "sdlew.h"
 #endif
@@ -538,6 +555,54 @@ static EnumPropertyItem *rna_userdef_compute_device_itemf(bContext *UNUSED(C), P
 }
 #endif
 
+#ifdef WITH_OPENSUBDIV
+static EnumPropertyItem *rna_userdef_opensubdiv_compute_type_itemf(bContext *UNUSED(C), PointerRNA *UNUSED(ptr),
+                                                                   PropertyRNA *UNUSED(prop), bool *r_free)
+{
+	EnumPropertyItem *item = NULL;
+	int totitem = 0;
+	int evaluators = openSubdiv_getAvailableEvaluators();
+
+	RNA_enum_items_add_value(&item, &totitem, opensubdiv_compute_type_items, USER_OPENSUBDIV_COMPUTE_NONE);
+
+#define APPEND_COMPUTE(compute) \
+	if (evaluators & OPENSUBDIV_EVALUATOR_## compute) { \
+		RNA_enum_items_add_value(&item, &totitem, opensubdiv_compute_type_items, USER_OPENSUBDIV_COMPUTE_ ## compute); \
+	} ((void)0)
+
+	APPEND_COMPUTE(CPU);
+	APPEND_COMPUTE(OPENMP);
+	APPEND_COMPUTE(OPENCL);
+	APPEND_COMPUTE(CUDA);
+	APPEND_COMPUTE(GLSL_TRANSFORM_FEEDBACK);
+	APPEND_COMPUTE(GLSL_COMPUTE);
+
+#undef APPEND_COMPUTE
+
+	RNA_enum_item_end(&item, &totitem);
+	*r_free = true;
+
+	return item;
+}
+
+static void rna_userdef_opensubdiv_update(Main *bmain, Scene *UNUSED(scene), PointerRNA *UNUSED(ptr))
+{
+	Object *object;
+
+	for (object = bmain->object.first;
+	     object;
+	     object = object->id.next)
+	{
+		if (object->derivedFinal != NULL &&
+		    object->derivedFinal->type == DM_TYPE_CCGDM)
+		{
+			DAG_id_tag_update(&object->id, OB_RECALC_OB);
+		}
+	}
+}
+
+#endif
+
 static EnumPropertyItem *rna_userdef_audio_device_itemf(bContext *UNUSED(C), PointerRNA *UNUSED(ptr),
                                                         PropertyRNA *UNUSED(prop), bool *r_free)
 {
@@ -4204,6 +4269,16 @@ static void rna_def_userdef_system(BlenderRNA *brna)
 	RNA_def_property_enum_funcs(prop, "rna_userdef_compute_device_get", NULL, "rna_userdef_compute_device_itemf");
 	RNA_def_property_ui_text(prop, "Compute Device", "Device to use for computation");
 #endif
+
+#ifdef WITH_OPENSUBDIV
+	prop = RNA_def_property(srna, "opensubdiv_compute_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_flag(prop, PROP_ENUM_NO_CONTEXT);
+	RNA_def_property_enum_sdna(prop, NULL, "opensubdiv_compute_type");
+	RNA_def_property_enum_items(prop, opensubdiv_compute_type_items);
+	RNA_def_property_enum_funcs(prop, NULL, NULL, "rna_userdef_opensubdiv_compute_type_itemf");
+	RNA_def_property_ui_text(prop, "OpenSubdiv Compute Type", "Type of computer backend used with OpenSubdiv");
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_PROPERTIES, "rna_userdef_opensubdiv_update");
+#endif
 }
 
 static void rna_def_userdef_input(BlenderRNA *brna)