watercolor.glsl

  const int AMOUNT = 25;

  void main () {
    float TIME = uTime * 1.0;
    
    vec2 uv = scale * (gl_FragCoord.xy - .5 * uResolution.xy) / uResolution.y;
    // uv *= rotate(uv, angle1);
    uv.x *= 0.85;
    uv.y += 10.;

    // Distort uvs
    for(int n = 1; n < AMOUNT; n++){
      float i = float(n);

      uv += vec2(
        0.7 / i * sin(i * uv.y * freq1 + TIME + 0.6 * i) + 0.9,
        0.4 / i + sin((uv.x) + TIME + 0.3 * i) + 1.6
      );
    }

    // Colors
    vec3 c1 = vec3(0.111, 0.005, 0.115);
    vec3 c2 = vec3(0.770, 0.005, 0.742);
    vec3 c3 = vec3(0.185, 0.849, 1.000);
    vec3 c4 = vec3(0.813, 0.895, 0.981);
    vec3 c5 = vec3(0.019, 0.000, 0.026);

    vec3 color = vec3(
      0.5 * sin(uv.x * freq1 + uTime) * amp1,
      0.5 * sin(uv.y * 1.) + 0.5,
      0.5 * sin((uv.x + uv.y) * 4.)
    );

    float x0 = clamp(color.r * 0.8 + color.g * color.b, 0., 1.);

    float p1 = smoothstep(0., 0.5, x0);
    float p2 = smoothstep(0.0, 1.0, x0);
    float p3 = smoothstep(0.5, 0.75, x0);
    float p4 = smoothstep(0.75, 1., x0);

    vec3 mix1 = mix(c1, c2, p1);
    vec3 mix2 = mix(mix1, c3, p2);
    vec3 mix3 = mix(mix2, c4, p3);
    vec3 mix4 = mix(mix3, c5, p4);

    float shadow = clamp(color.b, 0., 1.);
    vec3 final = mix2;
    final += shadow;
    final += random(vUv * 4.) * 0.1;

    gl_FragColor = vec4(final, 1.0);
  }