Fix T49467: Crash due to assert failure in bevel.

The mesh interpolation code had an edge case where one of two
adjacent edges to a vertex has 0 length. This caused an assert
failure indexing the vertex mesh for splash Blenderman.blend.

1 files changed, 6 insertions, 4 deletions

diff --git a/source/blender/bmesh/tools/bmesh_bevel.c b/source/blender/bmesh/tools/bmesh_bevel.c
index 05169a2a976..a05c12a2730 100644
--- a/source/blender/bmesh/tools/bmesh_bevel.c
+++ b/source/blender/bmesh/tools/bmesh_bevel.c
@@ -2295,7 +2295,7 @@ static int interp_range(const float *frac, int n, const float f, float *r_rest)
 /* Interpolate given vmesh to make one with target nseg border vertices on the profiles */
 static VMesh *interp_vmesh(BevelParams *bp, VMesh *vm0, int nseg)
 {
-	int n, ns0, nseg2, odd, i, j, k, j0, k0, k0prev;
+	int n, ns0, nseg2, odd, i, j, k, j0, k0, k0prev, j0inc, k0inc;
 	float *prev_frac, *frac, *new_frac, *prev_new_frac;
 	float f, restj, restk, restkprev;
 	float quad[4][3], co[3], center[3];
@@ -2339,10 +2339,12 @@ static VMesh *interp_vmesh(BevelParams *bp, VMesh *vm0, int nseg)
 					copy_v3_v3(co, mesh_vert_canon(vm0, i, j0, k0)->co);
 				}
 				else {
+					j0inc = (restj < BEVEL_EPSILON || j0 == ns0) ? 0 : 1;
+					k0inc = (restk < BEVEL_EPSILON || k0 == ns0) ? 0 : 1;
 					copy_v3_v3(quad[0], mesh_vert_canon(vm0, i, j0, k0)->co);
-					copy_v3_v3(quad[1], mesh_vert_canon(vm0, i, j0, k0 + 1)->co);
-					copy_v3_v3(quad[2], mesh_vert_canon(vm0, i, j0 + 1, k0 + 1)->co);
-					copy_v3_v3(quad[3], mesh_vert_canon(vm0, i, j0 + 1, k0)->co);
+					copy_v3_v3(quad[1], mesh_vert_canon(vm0, i, j0, k0 + k0inc)->co);
+					copy_v3_v3(quad[2], mesh_vert_canon(vm0, i, j0 + j0inc, k0 + k0inc)->co);
+					copy_v3_v3(quad[3], mesh_vert_canon(vm0, i, j0 + j0inc, k0)->co);
 					interp_bilinear_quad_v3(quad, restk, restj, co);
 				}
 				copy_v3_v3(mesh_vert(vm1, i, j, k)->co, co);