diff --git a/js/retro.js b/js/retro.js
index 3d0872b..96858c6 100644
--- a/js/retro.js
+++ b/js/retro.js
@@ -26,7 +26,7 @@ export class RetroEffect {
           varying vec2 vUv;
           void main() {
             vUv = uv;
-            gl_Position = vec4(position, 0.0, 1.0);
+            gl_Position = vec4(position.xy, 0.0, 1.0);
           }
         `,
         fragmentShader: `