diff --git a/kwin/incinerate/onAnimationBegin.js b/kwin/incinerate/onAnimationBegin.js
index b077f37..de6a541 100644
--- a/kwin/incinerate/onAnimationBegin.js
+++ b/kwin/incinerate/onAnimationBegin.js
@@ -7,10 +7,10 @@ let startPos = seed[0] > seed[1] ? [seed[0], Math.floor(seed[1] + 0.5)] :
 
 if (effect.readConfig('UsePointer', true)) {
   startPos = [
-    (effects.cursorPos.x - window.x) / window.width,
-    (effects.cursorPos.y - window.y) / window.height
+    Math.min(1.0, Math.max(0.0, (effects.cursorPos.x - window.x) / window.width)),
+    Math.min(1.0, Math.max(0.0, (effects.cursorPos.y - window.y) / window.height))
   ];
 }
 
 effect.setUniform(this.shader, 'uSeed', seed);
-effect.setUniform(this.shader, 'uStartPos', startPos);
\ No newline at end of file
+effect.setUniform(this.shader, 'uStartPos', startPos);
diff --git a/kwin/pixel-wipe/onAnimationBegin.js b/kwin/pixel-wipe/onAnimationBegin.js
index 51f3f81..980edc6 100644
--- a/kwin/pixel-wipe/onAnimationBegin.js
+++ b/kwin/pixel-wipe/onAnimationBegin.js
@@ -2,8 +2,8 @@
 // The code below is called whenever a window is closed or opened.
 
 let startPos = [
-  (effects.cursorPos.x - window.x) / window.width,
-  (effects.cursorPos.y - window.y) / window.height
+  Math.min(1.0, Math.max(0.0, (effects.cursorPos.x - window.x) / window.width)),
+  Math.min(1.0, Math.max(0.0, (effects.cursorPos.y - window.y) / window.height))
 ];
 
-effect.setUniform(this.shader, 'uStartPos', startPos);
\ No newline at end of file
+effect.setUniform(this.shader, 'uStartPos', startPos);