diff --git a/Assets/uDesktopDuplication/Shaders/uDD_Common.cginc b/Assets/uDesktopDuplication/Shaders/uDD_Common.cginc
index b198817..7bbb632 100644
--- a/Assets/uDesktopDuplication/Shaders/uDD_Common.cginc
+++ b/Assets/uDesktopDuplication/Shaders/uDD_Common.cginc
@@ -98,11 +98,11 @@ inline void uddBendVertex(inout float4 v, half radius, half width, half thicknes
     half angle = width * v.x / radius;
     #ifdef _FORWARD_Z
     v.z *= thickness;
-    radius -= v.z;
+    radius += v.z;
     v.z -= radius * (1 - cos(angle));
     #elif _FORWARD_Y
     v.y *= thickness;
-    radius -= v.y;
+    radius += v.y;
     v.y += radius * (1 - cos(angle));
     #endif
     v.x = radius * sin(angle) / width;