Fix #4000

materialsLibrary/src/gradient/gradient.fragment.fx

@@ -12,6 +12,7 @@ uniform float smoothness;
 
 // Input
 varying vec3 vPositionW;
+varying vec3 vPosition;
 
 #ifdef NORMAL
 varying vec3 vNormalW;
@@ -51,7 +52,7 @@ void main(void) {
 
 	vec3 viewDirectionW = normalize(vEyePosition - vPositionW);
 
-    float h = normalize(vPositionW).y + offset;
+    float h = normalize(vPosition).y + offset;
     float mysmoothness = clamp(smoothness, 0.01, max(smoothness, 10.));
 
     vec4 baseColor = mix(bottomColor, topColor, max(pow(max(h, 0.0), mysmoothness), 0.0));

materialsLibrary/src/gradient/gradient.vertex.fx

@@ -35,6 +35,7 @@ uniform float pointSize;
 
 // Output
 varying vec3 vPositionW;
+varying vec3 vPosition;
 #ifdef NORMAL
 varying vec3 vNormalW;
 #endif
@@ -56,6 +57,7 @@ void main(void) {
 
 	vec4 worldPos = finalWorld * vec4(position, 1.0);
 	vPositionW = vec3(worldPos);
+	vPosition = position;
 
 #ifdef NORMAL
 	vNormalW = normalize(vec3(finalWorld * vec4(normal, 0.0)));