core: add some noise to the gradient effect.

src/gradient.lolfx

@@ -37,13 +37,17 @@ mat4 cluster = mat4(12.0,  5.0,  6.0, 13.0,
                     11.0,  3.0,  2.0,  8.0,
                     15.0, 10.0,  9.0, 14.0);
 
+float rand(vec2 p)
+{
+    return fract(sin(dot(p, vec2(12.9898, 78.2333))) * 123.4567);
+}
+
 void main()
 {
     vec4 col = pass_Color;
 #if defined GL_ES
     int dx = int(mod(gl_FragCoord.x, 4.0));
     int dy = int(mod(gl_FragCoord.y, 4.0));
-    /* Cluster */
     float t;
     if (dx == 0)
     {
@@ -65,6 +69,7 @@ void main()
     float t = cluster[int(mod(gl_FragCoord.x, 4.0))]
                      [int(mod(gl_FragCoord.y, 4.0))];
 #endif
+    t += rand(gl_FragCoord.xy) - 0.5;
     t = (t + 0.5) / 17.0;
     col.x += fract(t - col.x) - t;
     col.y += fract(t - col.y) - t;