Cycles Standalone: Fix support for subdivision meshes

Changes from microdisplacement work broke previous support for subdivision
meshes, sometimes leading to crashes; this makes things work again. Files
that contain "patch" nodes will need to be updated to use meshes instead, as
specifying patches was both inefficient and completely unsupported by the new
subdivision code.

1 files changed, 28 insertions, 2 deletions

diff --git a/intern/cycles/render/mesh.cpp b/intern/cycles/render/mesh.cpp
index 257e83171e9..b02b9b792b7 100644
--- a/intern/cycles/render/mesh.cpp
+++ b/intern/cycles/render/mesh.cpp
@@ -500,7 +500,7 @@ void Mesh::add_vertex_normals()
 	size_t triangles_size = num_triangles();
 
 	/* static vertex normals */
-	if(!attributes.find(ATTR_STD_VERTEX_NORMAL)) {
+	if(!attributes.find(ATTR_STD_VERTEX_NORMAL) && triangles_size) {
 		/* get attributes */
 		Attribute *attr_fN = attributes.find(ATTR_STD_FACE_NORMAL);
 		Attribute *attr_vN = attributes.add(ATTR_STD_VERTEX_NORMAL);
@@ -529,7 +529,7 @@ void Mesh::add_vertex_normals()
 	Attribute *attr_mP = attributes.find(ATTR_STD_MOTION_VERTEX_POSITION);
 	Attribute *attr_mN = attributes.find(ATTR_STD_MOTION_VERTEX_NORMAL);
 
-	if(has_motion_blur() && attr_mP && !attr_mN) {
+	if(has_motion_blur() && attr_mP && !attr_mN && triangles_size) {
 		/* create attribute */
 		attr_mN = attributes.add(ATTR_STD_MOTION_VERTEX_NORMAL);
 
@@ -556,6 +556,32 @@ void Mesh::add_vertex_normals()
 			}
 		}
 	}
+
+	/* subd vertex normals */
+	if(!subd_attributes.find(ATTR_STD_VERTEX_NORMAL) && subd_faces.size()) {
+		/* get attributes */
+		Attribute *attr_vN = subd_attributes.add(ATTR_STD_VERTEX_NORMAL);
+		float3 *vN = attr_vN->data_float3();
+
+		/* compute vertex normals */
+		memset(vN, 0, verts.size()*sizeof(float3));
+
+		for(size_t i = 0; i < subd_faces.size(); i++) {
+			SubdFace& face = subd_faces[i];
+
+			for(size_t j = 0; j < face.num_corners; j++) {
+				size_t corner = subd_face_corners[face.start_corner+j];
+				vN[corner] += verts[corner];
+			}
+		}
+
+		for(size_t i = 0; i < verts_size; i++) {
+			vN[i] = normalize(vN[i]);
+			if(flip) {
+				vN[i] = -vN[i];
+			}
+		}
+	}
 }
 
 void Mesh::pack_normals(Scene *scene, uint *tri_shader, float4 *vnormal)