71 lines
No EOL
1.7 KiB
GLSL
71 lines
No EOL
1.7 KiB
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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// Tweaked from http://glsl.heroku.com/e#5893.0
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uniform mat3 outputToWorld;
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uniform vec4 color1;
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uniform vec4 color2;
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uniform float time;
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vec2 Distort(vec2 p)
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{
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float theta = atan(p.y, p.x);
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float radius = length(p);
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radius = pow(radius, 1.3);
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p.x = radius * cos(theta);
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p.y = radius * sin(theta);
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return 0.5 * (p + 1.0);
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}
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vec4 pattern(vec2 p)
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{
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vec2 m=mod(p.xy+p.x+p.y,2.)-1.;
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return vec4(length(m));
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}
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float hash(const float n)
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{
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return fract(sin(n)*43758.5453);
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}
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float noise(const vec3 x)
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{
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vec3 p=floor(x);
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vec3 f=fract(x);
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f=f*f*(3.0-2.0*f);
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float n=p.x+p.y*57.0+p.z*43.0;
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float r1=mix(mix(hash(n+0.0),hash(n+1.0),f.x),mix(hash(n+57.0),hash(n+57.0+1.0),f.x),f.y);
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float r2=mix(mix(hash(n+43.0),hash(n+43.0+1.0),f.x),mix(hash(n+43.0+57.0),hash(n+43.0+57.0+1.0),f.x),f.y);
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return mix(r1,r2,f.z);
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}
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void main( void )
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{
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vec2 position = .01 * (outputToWorld * vec3(gl_FragCoord.xy, 1.0)).xy;
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float off = noise(position.xyx + time);
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vec4 c = pattern(Distort(position+off));
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c.xy = Distort(c.xy);
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// ORIGINAL:
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// vec4(c.x - off, sin(c.y) - off, cos(c.z), 1.0);
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// The original green component did not show much. So, the original formula can be written
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// as a linear combination of those R and B channels - we generalize that to 2 arbitrary
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// colors. Plus, the resulting color is required to be in a premultiplied form.
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vec4 col1 = vec4(color1.rgb * color1.a, color1.a); // Premultiplication
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vec4 col2 = vec4(color2.rgb * color2.a, color2.a); //
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float coeff1 = c.x - off, coeff2 = cos(c.z);
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gl_FragColor = (coeff1 * col1 + coeff2 * col2) / (coeff1 + coeff2);
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} |