mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
56 lines
1.6 KiB
GLSL
56 lines
1.6 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 vec2 u_mouse;
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uniform float u_time;
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float random (in float x) { return fract(sin(x)*1e4); }
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float random (in vec2 _st) { return fract(sin(dot(_st.xy, vec2(12.9898,78.233)))* 43758.5453123);}
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void main() {
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vec2 st = gl_FragCoord.xy/u_resolution.xy;
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st.x *= u_resolution.x/u_resolution.y;
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// Grid
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vec2 grid = vec2(100.0,50.);
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st *= grid;
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vec2 ipos = floor(st); // integer
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vec2 vel = floor(vec2(u_time*10.)); // time
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vel *= vec2(-1.,0.); // direction
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vel *= (step(1., mod(ipos.y,2.0))-0.5)*2.; // Oposite directions
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vel *= random(ipos.y); // random speed
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// 100%
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float totalCells = grid.x*grid.y;
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float t = mod(u_time*max(grid.x,grid.y)+floor(1.0+u_time*u_mouse.y),totalCells);
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vec2 head = vec2(mod(t,grid.x), floor(t/grid.x));
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vec2 offset = vec2(0.1,0.);
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vec3 color = vec3(1.0);
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color *= step(grid.y-head.y,ipos.y); // Y
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color += (1.0-step(head.x,ipos.x))*step(grid.y-head.y,ipos.y+1.); // X
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color = clamp(color,vec3(0.),vec3(1.));
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// Assign a random value base on the integer coord
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color.r *= random(floor(st+vel+offset));
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color.g *= random(floor(st+vel));
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color.b *= random(floor(st+vel-offset));
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color = smoothstep(0.,.5+u_mouse.x/u_resolution.x*.5,color*color); // smooth
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color = step(0.5+u_mouse.x/u_resolution.x*0.5,color); // threshold
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// Margin
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color *= step(.1,fract(st.x+vel.x))*step(.1,fract(st.y+vel.y));
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gl_FragColor = vec4(color,1.0);
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}
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