mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
36 lines
915 B
GLSL
36 lines
915 B
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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#define TWO_PI 6.28318530718
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uniform vec2 u_resolution;
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uniform float u_time;
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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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// Use polar coordinates instead of cartesian
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vec2 toCenter = vec2(0.5)-st;
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float angle = atan(toCenter.y,toCenter.x);
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float radius = length(toCenter)*2.0;
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// Map the angle (-PI to PI) to the Hue (from 0 to 1)
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// and the Saturation to the radius
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color = hsb2rgb(vec3((angle/TWO_PI)+0.5,radius,1.0));
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gl_FragColor = vec4(color,1.0);
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}
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