diff --git a/examples/shader/default.go b/examples/shader/default.go
index f23f5df55..6150431fc 100644
--- a/examples/shader/default.go
+++ b/examples/shader/default.go
@@ -21,8 +21,12 @@ var Cursor vec2
 var ScreenSize vec2
 
 func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
-	// Note that the value of position.xy is indeterministic as the destination image is somewhere on a texture atlas.
-	pos := position.xy/imageDstTextureSize() + Cursor/ScreenSize/4
+	// Normalize the position to [0, 1].
+	pos := position.xy / imageDstTextureSize()
+	origin, size := imageDstRegionOnTexture()
+	pos -= origin
+	pos /= size
+	pos += Cursor / ScreenSize / 4
 	clr := 0.0
 	clr += sin(pos.x*cos(Time/15)*80) + cos(pos.y*cos(Time/15)*10)
 	clr += sin(pos.y*sin(Time/10)*40) + cos(pos.x*sin(Time/25)*40)