werid: add voronoi growth

weird/voronoi_growth.frag

@@ -0,0 +1,57 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2 u_resolution;
+uniform float u_time;
+
+const mat2 myt = mat2(.12121212, .13131313, -.13131313, .12121212);
+const vec2 mys = vec2(1e4, 1e6);
+
+vec2 rhash(vec2 uv) {
+  uv *= myt;
+  uv *= mys;
+  return fract(fract(uv / mys) * uv);
+}
+
+vec3 hash(vec3 p) {
+  return fract(sin(vec3(dot(p, vec3(1.0, 57.0, 113.0)),
+                        dot(p, vec3(57.0, 113.0, 1.0)),
+                        dot(p, vec3(1.0, 112.0, 57.0)))) *
+               43758.5453);
+}
+
+vec3 voronoi3d(const in vec3 x) {
+  vec3 p = floor(x);
+  vec3 f = fract(x);
+
+  float id = 0.0;
+  vec2 res = vec2(100.0);
+  for (int k = -1; k <= 1; k++) {
+    for (int j = -1; j <= 1; j++) {
+      for (int i = -1; i <= 1; i++) {
+        vec3 b = vec3(float(i), float(j), float(k));
+        vec3 r = vec3(b) - f + hash(p + b);
+        float d = dot(r, r);
+
+        if (d < res.x) {
+          id = dot(p + b, vec3(1.0, 57.0, 113.0));
+          res = vec2(d, res.x);
+        } else if (d < res.y) {
+          res.y = d;
+        }
+      }
+    }
+  }
+
+  return vec3(sqrt(res), id);
+}
+
+void main() {
+    vec2 st = gl_FragCoord.xy/u_resolution.xy;
+    st*=30.;    
+    st.x *= u_resolution.x/u_resolution.y;
+    gl_FragColor.rgb = voronoi3d(vec3(st, -14.2*(abs(cos(u_time*0.1))+0.01)));
+    gl_FragColor.r = (st.x)/66.+(st.y)/66.;
+    gl_FragColor.a   = 1.0;
+}