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, 4 insertions, 0 deletions

diff --git a/intern/cycles/render/scene.h b/intern/cycles/render/scene.h
index 05e807ff60c..9e72f197cce 100644
--- a/intern/cycles/render/scene.h
+++ b/intern/cycles/render/scene.h
@@ -74,10 +74,14 @@ public:
 	device_vector<uint> tri_shader;
 	device_vector<float4> tri_vnormal;
 	device_vector<uint4> tri_vindex;
+	device_vector<uint> tri_patch;
+	device_vector<float2> tri_patch_uv;
 
 	device_vector<float4> curves;
 	device_vector<float4> curve_keys;
 
+	device_vector<uint> patches;
+
 	/* objects */
 	device_vector<float4> objects;
 	device_vector<float4> objects_vector;