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, 3 insertions, 4 deletions

diff --git a/intern/cycles/kernel/osl/osl_services.cpp b/intern/cycles/kernel/osl/osl_services.cpp
index 2bb2be5e6b3..caae24405f1 100644
--- a/intern/cycles/kernel/osl/osl_services.cpp
+++ b/intern/cycles/kernel/osl/osl_services.cpp
@@ -787,7 +787,7 @@ bool OSLRenderServices::get_attribute(ShaderData *sd, bool derivatives, ustring
                                       TypeDesc type, ustring name, void *val)
 {
 	KernelGlobals *kg = sd->osl_globals;
-	bool is_curve;
+	int prim_type = 0;
 	int object;
 
 	/* lookup of attribute on another object */
@@ -798,18 +798,17 @@ bool OSLRenderServices::get_attribute(ShaderData *sd, bool derivatives, ustring
 			return false;
 
 		object = it->second;
-		is_curve = false;
 	}
 	else {
 		object = sd->object;
-		is_curve = (sd->type & PRIMITIVE_ALL_CURVE) != 0;
+		prim_type = attribute_primitive_type(kg, sd);
 
 		if(object == OBJECT_NONE)
 			return get_background_attribute(kg, sd, name, type, derivatives, val);
 	}
 
 	/* find attribute on object */
-	object = object*ATTR_PRIM_TYPES + (is_curve == true);
+	object = object*ATTR_PRIM_TYPES + prim_type;
 	OSLGlobals::AttributeMap& attribute_map = kg->osl->attribute_map[object];
 	OSLGlobals::AttributeMap::iterator it = attribute_map.find(name);