knife sort_by_frac_along was re-calculating the reference factor for every test, change to only calculate once and use line_point_factor_v3().

also add zero division check for line_point_factor_v3() since the 2d version already checked for this.

2 files changed, 15 insertions, 23 deletions

diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index 56921797659..c8de9108fc3 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -1654,9 +1654,16 @@ float closest_to_line_v2(float cp[2], const float p[2], const float l1[2], const
 float line_point_factor_v3(const float p[3], const float l1[3], const float l2[3])
 {
 	float h[3], u[3];
+	float dot;
 	sub_v3_v3v3(u, l2, l1);
 	sub_v3_v3v3(h, p, l1);
+#if 0
 	return (dot_v3v3(u, h) / dot_v3v3(u, u));
+#else
+	/* better check for zero */
+	dot = dot_v3v3(u, u);
+	return (dot != 0.0f) ? (dot_v3v3(u, h) / dot) : 0.0f;
+#endif
 }
 
 float line_point_factor_v2(const float p[2], const float l1[2], const float l2[2])
diff --git a/source/blender/editors/mesh/editmesh_knife.c b/source/blender/editors/mesh/editmesh_knife.c
index afd151f3c77..5957e71c57c 100644
--- a/source/blender/editors/mesh/editmesh_knife.c
+++ b/source/blender/editors/mesh/editmesh_knife.c
@@ -2212,43 +2212,28 @@ static void knifenet_fill_faces(KnifeTool_OpData *kcd)
 
 #else  /* use direct (non-scanfill) method for cuts */
 
-/* assuming v is on line ab, what fraction of the way is v from a to b? */
-static float frac_along(const float a[3], const float b[3], const float v[3])
-{
-	float lab;
-
-	lab = len_v3v3(a, b);
-	if (lab == 0.0f) {
-		return 0.0f;
-	}
-	else {
-		return len_v3v3(a, v) / lab;
-	}
-}
-
 /* sort list of kverts by fraction along edge e */
 static void sort_by_frac_along(ListBase *lst, BMEdge *e)
 {
-	KnifeVert *vcur, *vprev;
-	float *v1co, *v2co;
+	const float *v1co = e->v1->co;
+	const float *v2co = e->v2->co;
 	Ref *cur = NULL, *prev = NULL, *next = NULL;
 
 	if (lst->first == lst->last)
 		return;
 
-	v1co = e->v1->co;
-	v2co = e->v2->co;
-
 	for (cur = ((Ref *)lst->first)->next; cur; cur = next) {
+		KnifeVert *vcur = cur->ref;
+		const float vcur_fac = line_point_factor_v3(vcur->co, v1co, v2co);
+
 		next = cur->next;
 		prev = cur->prev;
 
 		BLI_remlink(lst, cur);
 
-		vcur = cur->ref;
 		while (prev) {
-			vprev = prev->ref;
-			if (frac_along(v1co, v2co, vprev->co) <= frac_along(v1co, v2co, vcur->co))
+			KnifeVert *vprev = prev->ref;
+			if (line_point_factor_v3(vprev->co, v1co, v2co) <= vcur_fac)
 				break;
 			prev = prev->prev;
 		}
@@ -2860,7 +2845,7 @@ static void knife_make_cuts(KnifeTool_OpData *kcd)
 		sort_by_frac_along(lst, e);
 		for (ref = lst->first; ref; ref = ref->next) {
 			kfv = ref->ref;
-			pct = frac_along(e->v1->co, e->v2->co, kfv->co);
+			pct = line_point_factor_v3(kfv->co, e->v1->co, e->v2->co);
 			kfv->v = BM_edge_split(bm, e, e->v1, &enew, pct);
 		}
 	}