Fix T37177, sculpting can act on opposite side of mesh in orthographic camera.

Summary:
Issue here most probably is that the start point in ray-casting is too
far away from the mesh. As a result the triangle intersection code can
sometimes miss the ray intersection. To solve this, we project the ray
segment to the boundary of the root node.

Reviewers: brecht, sergey, campbellbarton

Reviewed By: brecht

Maniphest Tasks: T37177

Differential Revision: http://developer.blender.org/D115

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_pbvh.h b/source/blender/blenkernel/BKE_pbvh.h
index f8c21a1fa16..7ef120e26af 100644
--- a/source/blender/blenkernel/BKE_pbvh.h
+++ b/source/blender/blenkernel/BKE_pbvh.h
@@ -97,6 +97,12 @@ int BKE_pbvh_node_raycast(PBVH *bvh, PBVHNode *node, float (*origco)[3], int use
                           const float ray_start[3], const float ray_normal[3],
                           float *dist);
 
+/* for orthographic cameras, project the far away ray segment points to the root node so
+ * we can have better precision. Warning, this function assumes that ray begins and ends outside
+ * bounding box! */
+void BKE_pbvh_raycast_project_ray_root(PBVH *bvh, bool original, float ray_start[3],
+                                       float ray_end[3], float ray_normal[3]);
+
 /* Drawing */
 
 void BKE_pbvh_node_draw(PBVHNode *node, void *data);