Cycles microdisplacement: Support for Catmull-Clark subdivision via OpenSubdiv

Enables Catmull-Clark subdivision meshes with support for creases and attribute
subdivision. Still waiting on OpenSubdiv to fully support face varying
interpolation for subdividing uv coordinates tho. Also there may be some
inconsistencies with Blender's subdivision which will be resolved at a
later time.

Code for reading patch tables and creating patch maps is borrowed
from OpenSubdiv.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2111

1 files changed, 38 insertions, 4 deletions

diff --git a/intern/cycles/blender/blender_mesh.cpp b/intern/cycles/blender/blender_mesh.cpp
index 74fd4cb44a0..b4c490c0d33 100644
--- a/intern/cycles/blender/blender_mesh.cpp
+++ b/intern/cycles/blender/blender_mesh.cpp
@@ -409,7 +409,8 @@ static void attr_create_uv_map(Scene *scene,
                                BL::Mesh& b_mesh,
                                const vector<int>& nverts,
                                const vector<int>& face_flags,
-                               bool subdivision)
+                               bool subdivision,
+                               bool subdivide_uvs)
 {
 	if(subdivision) {
 		BL::Mesh::uv_layers_iterator l;
@@ -429,6 +430,10 @@ static void attr_create_uv_map(Scene *scene,
 				else
 					attr = mesh->subd_attributes.add(name, TypeDesc::TypePoint, ATTR_ELEMENT_CORNER);
 
+				if(subdivide_uvs) {
+					attr->flags |= ATTR_SUBDIVIDED;
+				}
+
 				BL::Mesh::polygons_iterator p;
 				float3 *fdata = attr->data_float3();
 
@@ -592,7 +597,8 @@ static void create_mesh(Scene *scene,
                         Mesh *mesh,
                         BL::Mesh& b_mesh,
                         const vector<Shader*>& used_shaders,
-                        bool subdivision=false)
+                        bool subdivision=false,
+                        bool subdivide_uvs=true)
 {
 	/* count vertices and faces */
 	int numverts = b_mesh.vertices.length();
@@ -638,6 +644,7 @@ static void create_mesh(Scene *scene,
 	/* create generated coordinates from undeformed coordinates */
 	if(mesh->need_attribute(scene, ATTR_STD_GENERATED)) {
 		Attribute *attr = attributes.add(ATTR_STD_GENERATED);
+		attr->flags |= ATTR_SUBDIVIDED;
 
 		float3 loc, size;
 		mesh_texture_space(b_mesh, loc, size);
@@ -746,7 +753,7 @@ static void create_mesh(Scene *scene,
 	 * The calculate functions will check whether they're needed or not.
 	 */
 	attr_create_vertex_color(scene, mesh, b_mesh, nverts, face_flags, subdivision);
-	attr_create_uv_map(scene, mesh, b_mesh, nverts, face_flags, subdivision);
+	attr_create_uv_map(scene, mesh, b_mesh, nverts, face_flags, subdivision, subdivide_uvs);
 
 	/* for volume objects, create a matrix to transform from object space to
 	 * mesh texture space. this does not work with deformations but that can
@@ -770,8 +777,35 @@ static void create_subd_mesh(Scene *scene,
                              float dicing_rate,
                              int max_subdivisions)
 {
-	create_mesh(scene, mesh, b_mesh, used_shaders, true);
+	BL::SubsurfModifier subsurf_mod(b_ob.modifiers[b_ob.modifiers.length()-1]);
+	bool subdivide_uvs = subsurf_mod.use_subsurf_uv();
+
+	create_mesh(scene, mesh, b_mesh, used_shaders, true, subdivide_uvs);
+
+	/* export creases */
+	size_t num_creases = 0;
+	BL::Mesh::edges_iterator e;
+
+	for(b_mesh.edges.begin(e); e != b_mesh.edges.end(); ++e) {
+		if(e->crease() != 0.0f) {
+			num_creases++;
+		}
+	}
+
+	mesh->subd_creases.resize(num_creases);
+
+	Mesh::SubdEdgeCrease* crease = mesh->subd_creases.data();
+	for(b_mesh.edges.begin(e); e != b_mesh.edges.end(); ++e) {
+		if(e->crease() != 0.0f) {
+			crease->v[0] = e->vertices()[0];
+			crease->v[1] = e->vertices()[1];
+			crease->crease = e->crease();
+
+			crease++;
+		}
+	}
 
+	/* set subd params */
 	SubdParams sdparams(mesh);
 
 	PointerRNA cobj = RNA_pointer_get(&b_ob.ptr, "cycles");