mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-08 01:10:27 +00:00
72 lines
1.9 KiB
GLSL
72 lines
1.9 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 sampler2D u_tex;
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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 noise(in vec2 x) {
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vec2 i = floor(x);
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vec2 f = fract(x);
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float a = random(i);
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float b = random(i + vec2(1.0, 0.0));
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float c = random(i + vec2(0.0, 1.0));
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float d = random(i + vec2(1.0, 1.0));
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vec2 u = f * f * (3.0 - 2.0 * f);
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return mix(a, b, u.x) + (c - a) * u.y * (1.0 - u.x) + (d - b) * u.x * u.y;
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}
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float fbm( in vec2 p ){
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float s = 0.0;
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float m = 0.0;
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float a = 0.5;
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for(int i=0; i<2; i++ ){
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s += a * noise(p);
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m += a;
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a *= 0.5;
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p *= 2.0;
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}
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return s/m;
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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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float aspect = u_resolution.x/u_resolution.y;
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vec2 grain_st = st-.5;
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float grain = 0.0;
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grain = mix(1., 0.9, dot(grain_st,grain_st) + (fbm(gl_FragCoord.xy*0.6)*0.1) );
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// Random blocks
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vec2 blocks_st = floor(st*vec2(5.*random(floor(u_time*10.)),10.*(1.+random(floor(u_time*3.))) ));
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float t = u_time*2.+random(blocks_st);
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float time_i = floor(t);
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float time_f = fract(t);
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float block = step(0.9,random(blocks_st+time_i))*(1.0-time_f);
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vec2 offset = vec2(block*0.01,block*0.005)+(1.0-grain)*.08;
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vec4 color = vec4(1.);
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color.r = texture2D(u_tex,st+offset).r;
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color.g = texture2D(u_tex,st).r;
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color.b = texture2D(u_tex,st-offset).r;
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color.a = max(texture2D(u_tex,st+offset).a,max(texture2D(u_tex,st).a, texture2D(u_tex,st-offset).a));
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if (block > .5) {
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color.rgb = abs(block*grain-color.rgb);
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}
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color.rgb *= 0.4+sin((st.y*3.1415+u_time)*500.);
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gl_FragColor = color;
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}
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