diff options
Diffstat (limited to 'source/blender/blenkernel/intern/subdiv_eval.c')
| -rw-r--r-- | source/blender/blenkernel/intern/subdiv_eval.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/source/blender/blenkernel/intern/subdiv_eval.c b/source/blender/blenkernel/intern/subdiv_eval.c index baee8a80f5a..201d308e096 100644 --- a/source/blender/blenkernel/intern/subdiv_eval.c +++ b/source/blender/blenkernel/intern/subdiv_eval.c @@ -184,8 +184,9 @@ void BKE_subdiv_eval_limit_point_and_derivatives(Subdiv *subdiv, { subdiv->evaluator->evaluateLimit(subdiv->evaluator, ptex_face_index, u, v, r_P, r_dPdu, r_dPdv); - /* NOTE: In a very rare occasions derivatives are evaluated to zeros. This happens, for example, - * in single vertex on Suzannne's nose (where two quads have 2 common edges). + /* NOTE: In a very rare occasions derivatives are evaluated to zeros or are exactly equal. + * This happens, for example, in single vertex on Suzannne's nose (where two quads have 2 common + * edges). * * This makes tangent space displacement (such as multires) impossible to be used in those * vertices, so those needs to be addressed in one way or another. @@ -195,7 +196,7 @@ void BKE_subdiv_eval_limit_point_and_derivatives(Subdiv *subdiv, * that giving totally unusable derivatives. */ if (r_dPdu != NULL && r_dPdv != NULL) { - if (is_zero_v3(r_dPdu) || is_zero_v3(r_dPdv)) { + if ((is_zero_v3(r_dPdu) || is_zero_v3(r_dPdv)) || equals_v3v3(r_dPdu, r_dPdv)) { subdiv->evaluator->evaluateLimit(subdiv->evaluator, ptex_face_index, u * 0.999f + 0.0005f, |