Cycles microdisplacement: ngons and attributes for subdivision meshes

This adds support for ngons and attributes on subdivision meshes. Ngons are
needed for proper attribute interpolation as well as correct Catmull-Clark
subdivision. Several changes are made to achieve this:

- new primitive `SubdFace` added to `Mesh`
- 3 more textures are used to store info on patches from subd meshes
- Blender export uses loop interface instead of tessface for subd meshes
- `Attribute` class is updated with a simplified way to pass primitive counts
  around and to support ngons.
- extra points for ngons are generated for O(1) attribute interpolation
- curves are temporally disabled on subd meshes to avoid various bugs with
  implementation
- old unneeded code is removed from `subd/`
- various fixes and improvements

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2108

1 files changed, 8 insertions, 2 deletions

diff --git a/intern/cycles/kernel/geom/geom_primitive.h b/intern/cycles/kernel/geom/geom_primitive.h
index b1b1e919e00..44734d1b70d 100644
--- a/intern/cycles/kernel/geom/geom_primitive.h
+++ b/intern/cycles/kernel/geom/geom_primitive.h
@@ -26,7 +26,10 @@ CCL_NAMESPACE_BEGIN
 ccl_device float primitive_attribute_float(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float *dx, float *dy)
 {
 	if(ccl_fetch(sd, type) & PRIMITIVE_ALL_TRIANGLE) {
-		return triangle_attribute_float(kg, sd, elem, offset, dx, dy);
+		if(subd_triangle_patch(kg, sd) == ~0)
+			return triangle_attribute_float(kg, sd, elem, offset, dx, dy);
+		else
+			return subd_triangle_attribute_float(kg, sd, elem, offset, dx, dy);
 	}
 #ifdef __HAIR__
 	else if(ccl_fetch(sd, type) & PRIMITIVE_ALL_CURVE) {
@@ -48,7 +51,10 @@ ccl_device float primitive_attribute_float(KernelGlobals *kg, const ShaderData *
 ccl_device float3 primitive_attribute_float3(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float3 *dx, float3 *dy)
 {
 	if(ccl_fetch(sd, type) & PRIMITIVE_ALL_TRIANGLE) {
-		return triangle_attribute_float3(kg, sd, elem, offset, dx, dy);
+		if(subd_triangle_patch(kg, sd) == ~0)
+			return triangle_attribute_float3(kg, sd, elem, offset, dx, dy);
+		else
+			return subd_triangle_attribute_float3(kg, sd, elem, offset, dx, dy);
 	}
 #ifdef __HAIR__
 	else if(ccl_fetch(sd, type) & PRIMITIVE_ALL_CURVE) {