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, 5 insertions, 2 deletions

diff --git a/intern/cycles/blender/blender_util.h b/intern/cycles/blender/blender_util.h
index 188d23d0c59..34405c3ea1a 100644
--- a/intern/cycles/blender/blender_util.h
+++ b/intern/cycles/blender/blender_util.h
@@ -45,14 +45,17 @@ static inline BL::Mesh object_to_mesh(BL::BlendData& data,
                                       BL::Scene& scene,
                                       bool apply_modifiers,
                                       bool render,
-                                      bool calc_undeformed)
+                                      bool calc_undeformed,
+                                      bool subdivision)
 {
 	BL::Mesh me = data.meshes.new_from_object(scene, object, apply_modifiers, (render)? 2: 1, false, calc_undeformed);
 	if((bool)me) {
 		if(me.use_auto_smooth()) {
 			me.calc_normals_split();
 		}
-		me.calc_tessface(true);
+		if(!subdivision) {
+			me.calc_tessface(true);
+		}
 	}
 	return me;
 }