[Bf-blender-cvs] [30963eecfb3] master: Fix T73450, crash when adding segments on bevel.

[Howard Trickey]

Commit: 30963eecfb3be0dd50624d54f2111e7f1ed49d6b
Author: Howard Trickey
Date:   Thu Jan 30 07:56:00 2020 -0500
Branches: master
https://developer.blender.org/rB30963eecfb3be0dd50624d54f2111e7f1ed49d6b

Fix T73450, crash when adding segments on bevel.

Needed to protect against a case where clamp overlap limited
the offset to approximately zero, and the snap-to-pipe code
would therefore encounter an almost degenerate profile and
fail in matrix inversion.

===================================================================

M	source/blender/bmesh/tools/bmesh_bevel.c

===================================================================

diff --git a/source/blender/bmesh/tools/bmesh_bevel.c b/source/blender/bmesh/tools/bmesh_bevel.c
index bc84c6872c4..d3b3541a539 100644
--- a/source/blender/bmesh/tools/bmesh_bevel.c
+++ b/source/blender/bmesh/tools/bmesh_bevel.c
@@ -4272,6 +4272,10 @@ static void snap_to_pipe_profile(BoundVert *vpipe, bool midline, float co[3])
 
   copy_v3_v3(va, pro->start);
   copy_v3_v3(vb, pro->end);
+  if (compare_v3v3(va, vb, BEVEL_EPSILON_D)) {
+    copy_v3_v3(co, va);
+    return;
+  }
 
   /* Get a plane with the normal pointing along the beveled edge */
   sub_v3_v3v3(edir, e->e->v1->co, e->e->v2->co);
@@ -4280,13 +4284,8 @@ static void snap_to_pipe_profile(BoundVert *vpipe, bool midline, float co[3])
   closest_to_plane_v3(va0, plane, va);
   closest_to_plane_v3(vb0, plane, vb);
   closest_to_plane_v3(vmid0, plane, pro->middle);
-  if (make_unit_square_map(va0, vmid0, vb0, m)) {
+  if (make_unit_square_map(va0, vmid0, vb0, m) && invert_m4_m4(minv, m)) {
     /* Transform co and project it onto superellipse */
-    if (!invert_m4_m4(minv, m)) {
-      /* shouldn't happen */
-      BLI_assert(!"failed inverse during pipe profile snap");
-      return;
-    }
     mul_v3_m4v3(p, minv, co);
     snap_to_superellipsoid(p, pro->super_r, midline);