mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-08 01:10:27 +00:00
49 lines
1.2 KiB
GLSL
49 lines
1.2 KiB
GLSL
// Author @patriciogv - 2015
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// http://patriciogonzalezvivo.com
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#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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float random(in float x){ return fract(sin(x)*43758.5453); }
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float random(in vec2 st){ return fract(sin(dot(st.xy ,vec2(12.9898,78.233))) * 43758.5453); }
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float randomChar(vec2 outer,vec2 inner){
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float grid = 5.;
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vec2 margin = vec2(.2,.05);
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vec2 borders = step(margin,inner)*step(margin,1.-inner);
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vec2 ipos = floor(inner*grid);
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vec2 fpos = fract(inner*grid);
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return step(.5,random(outer*64.+ipos)) * borders.x * borders.y * step(0.01,fpos.x) * step(0.01,fpos.y);
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}
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void main(){
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vec2 st = gl_FragCoord.st/u_resolution.xy;
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if (u_resolution.x > u_resolution.y) {
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st.x *= u_resolution.x/u_resolution.y;
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} else {
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st.y *= u_resolution.y/u_resolution.y;
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}
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vec3 color = vec3(0.0);
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float rows = 1.0;
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// rows = 3.0;
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rows = 12.0;
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//rows = 24.0;
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vec2 ipos = floor(st*rows);
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vec2 fpos = fract(st*rows);
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ipos += vec2(0.,floor(u_time*20.*random(ipos.x+1.)));
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float pct = 1.0;
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pct *= randomChar(ipos,fpos);
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// pct *= random(ipos);
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color = vec3(pct);
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gl_FragColor = vec4( color , 1.0);
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}
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