Made BLI_delaunay_2d_cdt_calc better at tiny feature elimination.

The 'random' unit tests and some examples from the new boolean code
triggered asserts and crashes. This fixes those.
There is a new flag in the input that optionally disables a pass
over input to snap segment edges to other segments.

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_delaunay_2d.h b/source/blender/blenlib/BLI_delaunay_2d.h
index fe81de5fc5e..9d853dd9509 100644
--- a/source/blender/blenlib/BLI_delaunay_2d.h
+++ b/source/blender/blenlib/BLI_delaunay_2d.h
@@ -104,6 +104,11 @@
  * If zero is supplied for epsilon, an internal value of 1e-8 used
  * instead, since this code will not work correctly if it is not allowed
  * to merge "too near" vertices.
+ *
+ * Normally, if epsilon is non-zero, there is an "input modify" pass which
+ * checks to see if some vertices are within epsilon of other edges, and
+ * snapping them to those edges if so. You can skip this pass by setting
+ * skip_input_modify to true. (This is also useful in some unit tests.)
  */
 typedef struct CDT_input {
   int verts_len;
@@ -115,6 +120,7 @@ typedef struct CDT_input {
   int *faces_start_table;
   int *faces_len_table;
   float epsilon;
+  bool skip_input_modify;
 } CDT_input;
 
 /**