fix: perlin

default/inc_functions.glsl

@@ -180,13 +180,19 @@ float noise_f(vec2 n, int f)
 
 vec2 perlin_gradient(vec2 p, int seed)
 {
-    return normalize(
+    vec2 v = normalize(
 
         vec2(
             rand(p.x * 12.34 + p.y * 56.78 + seed) * 2.0 - 1.0,
             rand(p.x * 56.78 + p.y * 12.34 + seed) * 2.0 - 1.0
         )
     );
+
+    if (length(v) == 0.) {
+        return vec2(1, 0);
+    }
+
+    return v;
 }
 
 float perlin(vec2 p, int seed)