mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
43 lines
1.1 KiB
GLSL
43 lines
1.1 KiB
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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uniform vec2 u_resolution;
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uniform float u_time;
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vec3 rgb2hsb( in vec3 c ){
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vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
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vec4 p = mix(vec4(c.bg, K.wz),
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vec4(c.gb, K.xy),
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step(c.b, c.g));
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vec4 q = mix(vec4(p.xyw, c.r),
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vec4(c.r, p.yzx),
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step(p.x, c.r));
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float d = q.x - min(q.w, q.y);
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float e = 1.0e-10;
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return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)),
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d / (q.x + e),
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q.x);
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}
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// Function from Iñigo Quiles
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// https://www.shadertoy.com/view/MsS3Wc
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vec3 hsb2rgb( in vec3 c ){
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vec3 rgb = clamp(abs(mod(c.x*6.0+vec3(0.0,4.0,2.0),
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6.0)-3.0)-1.0,
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0.0,
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1.0 );
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rgb = rgb*rgb*(3.0-2.0*rgb);
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return c.z * mix(vec3(1.0), rgb, c.y);
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}
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void main(){
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vec2 st = gl_FragCoord.xy/u_resolution;
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vec3 color = vec3(0.0);
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// We map x (0.0 - 1.0) to the hue (0.0 - 1.0)
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// And the y (0.0 - 1.0) to the brightness
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color = hsb2rgb(vec3(st.x,1.0,st.y));
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gl_FragColor = vec4(color,1.0);
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} |