+#version 100
+precision highp float;
+varying vec2 c;
+varying vec2 z;
+
+void main() {
+ float zx = z.x;
+ float zy = z.y;
+ const int maxiter = 64;
+ for (int iter = maxiter; iter > 0; iter--) {
+ float zx2 = zx * zx;
+ float zy2 = zy * zy;
+ if (zx2 * zy2 > 4.0) {
+ float index = float(iter) / float(maxiter);
+ gl_FragColor = vec4(index, 0.1, 1.0 - index / 2.0, 0.8 - index * index);
+ return;
+ }
+ zy = zx * zy * 2.0 + c.y;
+ zx = zx2 - zy2 + c.x;
+ }
+ gl_FragColor = vec4((sin(z.y) + 1.0) / 4.0,
+ (sin(z.x) + 1.0) / 4.0,
+ (sin(c.x) + 1.0) / 4.0,
+ 1.0);
+}