Add tessellation data to DerivedMesh (LoopTri)

This stores loop indices into the loop array giving easier acess
to data such as vertex-colors and UV's,
removing the need to store an MFace duplicate of custom-data.

This doesn't yet move all internal code from MFace to LoopTri just yet.

Only applies to:
- opengl drawing
- sculpting (pbvh)
- vertex/weight paint

Thanks to @psy-fi for review, fixes and improvements to drawing!

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index 359e2a97d9f..5734d0125c7 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -300,6 +300,11 @@ void map_to_sphere(float *r_u, float *r_v, const float x, const float y, const f
 
 /********************************** Normals **********************************/
 
+void accumulate_vertex_normals_tri(
+        float n1[3], float n2[3], float n3[3],
+        const float f_no[3],
+        const float co1[3], const float co2[3], const float co3[3]);
+
 void accumulate_vertex_normals(
         float n1[3], float n2[3], float n3[3], float n4[3],
         const float f_no[3],