Correct fix for r54164, the testcase I was using worked but different edge slide examples didn't.

Edge slide needed to check for concave ngons too.

add BM_loop_is_convex() and expose to python too.

2 files changed, 19 insertions, 1 deletions

diff --git a/source/blender/bmesh/intern/bmesh_queries.c b/source/blender/bmesh/intern/bmesh_queries.c
index 7ed23aaf1f8..bf30db78a61 100644
--- a/source/blender/bmesh/intern/bmesh_queries.c
+++ b/source/blender/bmesh/intern/bmesh_queries.c
@@ -1007,6 +1007,22 @@ void BM_edge_ordered_verts(BMEdge *edge, BMVert **r_v1, BMVert **r_v2)
 }
 
 /**
+ * Check if the loop is convex or concave
+ * (depends on face normal)
+ */
+bool BM_loop_is_convex(BMLoop *l)
+{
+	float e_dir_prev[3];
+	float e_dir_next[3];
+	float l_no[3];
+
+	sub_v3_v3v3(e_dir_prev, l->prev->v->co, l->v->co);
+	sub_v3_v3v3(e_dir_next, l->next->v->co, l->v->co);
+	cross_v3_v3v3(l_no, e_dir_next, e_dir_prev);
+	return dot_v3v3(l_no, l->f->no) > 0.0f;
+}
+
+/**
  * Calculates the angle between the previous and next loops
  * (angle at this loops face corner).
  *
@@ -1034,7 +1050,7 @@ void BM_loop_calc_face_normal(BMLoop *l, float r_normal[3])
 	                  l->v->co,
 	                  l->next->v->co) != 0.0f)
 	{
-		return;
+		/* pass */
 	}
 	else {
 		copy_v3_v3(r_normal, l->f->no);
diff --git a/source/blender/bmesh/intern/bmesh_queries.h b/source/blender/bmesh/intern/bmesh_queries.h
index 9892700162e..4172b3905cd 100644
--- a/source/blender/bmesh/intern/bmesh_queries.h
+++ b/source/blender/bmesh/intern/bmesh_queries.h
@@ -62,6 +62,8 @@ bool    BM_vert_is_manifold(BMVert *v);
 bool    BM_edge_is_manifold(BMEdge *e);
 bool    BM_edge_is_boundary(BMEdge *e);
 
+bool    BM_loop_is_convex(BMLoop *l);
+
 float   BM_loop_calc_face_angle(BMLoop *l);
 void    BM_loop_calc_face_normal(BMLoop *l, float r_normal[3]);
 void    BM_loop_calc_face_tangent(BMLoop *l, float r_tangent[3]);