2 uniform vec3 uHSVDelta;
3 varying mediump vec2 vTexCoord;
4 uniform sampler2D sTexture;
8 return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
13 vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
14 vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
15 vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
17 float d = q.x - min(q.w, q.y);
19 return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
24 vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
25 vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
26 return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
31 vec4 color = texture2D(sTexture, vTexCoord);
32 vec3 hsvColor = rgb2hsv( color.rgb );
33 // modify the hsv Value
34 hsvColor += uHSVDelta * rand(vTexCoord);
35 // if the new vale exceeds one, then decrease it
36 hsvColor -= max(hsvColor*2.0 - vec3(2.0), 0.0);
37 // if the new vale drops below zero, then increase it
38 hsvColor -= min(hsvColor*2.0, 0.0);
39 color = vec4( hsv2rgb( hsvColor ), 1.0 );