diff --git a/examples/test/shaders/test.frag b/examples/test/shaders/test.frag
index e3736b4..997780d 100644
--- a/examples/test/shaders/test.frag
+++ b/examples/test/shaders/test.frag
@@ -40,9 +40,9 @@ vec3 estimate_scene_normal(vec3 p) {
 	vec3 dz = vec3(0, 0, GRAD_EPSILON);
 
 	return normalize(vec3(
-		scene_f(p + dx) - scene_f(p - dx),
-		scene_f(p + dy) - scene_f(p - dy),
-		scene_f(p + dz) - scene_f(p - dz)
+		scene_f(p + dx).d - scene_f(p - dx).d,
+		scene_f(p + dy).d - scene_f(p - dy).d,
+		scene_f(p + dz).d - scene_f(p - dz).d
 	));
 }