diff --git a/sample/stencilMask/main.ts b/sample/stencilMask/main.ts
index fb9f18b8..61f40a59 100644
--- a/sample/stencilMask/main.ts
+++ b/sample/stencilMask/main.ts
@@ -64,11 +64,11 @@ canvas.addEventListener('wheel', (e) => {
 canvas.addEventListener('mousemove', (e) => {
   const halfCanvasWidth = canvas.clientWidth / 2;
   const quarterCanvasWidth = canvas.clientWidth / 4;
-  const halfCanvasHeight = canvas.clientHeight / 2
+  const halfCanvasHeight = canvas.clientHeight / 2;
   const quarterCanvasHeight = canvas.clientHeight / 4;
 
   const halfCanvasHeight = canvas.clientHeight / 2;
-  settings.offsetX = (e.clientX - 3 * quarterCanvasWidth) / halfCanvasWidth
+  settings.offsetX = (e.clientX - 3 * quarterCanvasWidth) / halfCanvasWidth;
   settings.offsetY = (e.clientY - 3 * quarterCanvasHeight) / halfCanvasHeight;
 });