Fix #20196: division by zero in edge slide with two overlapping loops.

2 files changed, 6 insertions, 5 deletions

diff --git a/source/blender/editors/transform/transform.c b/source/blender/editors/transform/transform.c
index beea3c9bee4..86fdb81e0d9 100644
--- a/source/blender/editors/transform/transform.c
+++ b/source/blender/editors/transform/transform.c
@@ -4780,10 +4780,11 @@ int doEdgeSlide(TransInfo *t, float perc)
 		//Non prop code
 		look = vertlist;
 		while(look) {
-			float newlen;
+			float newlen, edgelen;
 			ev = look->link;
 			tempsv = BLI_ghash_lookup(vertgh,ev);
-			newlen = (len / len_v3v3(editedge_getOtherVert(tempsv->up,ev)->co,editedge_getOtherVert(tempsv->down,ev)->co));
+			edgelen = len_v3v3(editedge_getOtherVert(tempsv->up,ev)->co,editedge_getOtherVert(tempsv->down,ev)->co);
+			newlen = (edgelen != 0.0f)? (len / edgelen): 0.0f;
 			if(newlen > 1.0) {newlen = 1.0;}
 			if(newlen < 0.0) {newlen = 0.0;}
 			if(flip == 0) {
diff --git a/source/blender/editors/transform/transform_input.c b/source/blender/editors/transform/transform_input.c
index d7ebd28f604..b7cb34802cc 100644
--- a/source/blender/editors/transform/transform_input.c
+++ b/source/blender/editors/transform/transform_input.c
@@ -197,17 +197,17 @@ void InputCustomRatio(TransInfo *t, MouseInput *mi, short mval[2], float output[
 			mdx = (mi->precision_mval[0] + (float)(mval[0] - mi->precision_mval[0]) / 10.0f) - data[2];
 			mdy = (mi->precision_mval[1] + (float)(mval[1] - mi->precision_mval[1]) / 10.0f) - data[3];
 
-			distance = (mdx*dx + mdy*dy) / length;
+			distance = (length != 0.0f)? (mdx*dx + mdy*dy) / length: 0.0f;
 		}
 		else {
 			short mdx, mdy;
 			mdx = mval[0] - data[2];
 			mdy = mval[1] - data[3];
 
-			distance = (mdx*dx + mdy*dy) / length;
+			distance = (length != 0.0f)? (mdx*dx + mdy*dy) / length: 0.0f;
 		}
 
-		output[0] = distance / length;
+		output[0] = (length != 0.0f)? distance / length: 0.0f;
 	}
 }