mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
66 lines
1.5 KiB
GLSL
66 lines
1.5 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 vec2 st) {
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return fract(sin(dot(st.xy,
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vec2(12.9898,78.233)))
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* 43758.5453123);
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}
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// Based on Morgan McGuire @morgan3d
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// https://www.shadertoy.com/view/4dS3Wd
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float noise (in vec2 st) {
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vec2 i = floor(st);
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vec2 f = fract(st);
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// Four corners in 2D of a tile
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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) +
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(c - a)* u.y * (1.0 - u.x) +
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(d - b) * u.x * u.y;
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}
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mat2 rotate2d(float angle){
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return mat2(cos(angle),-sin(angle),
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sin(angle),cos(angle));
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}
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float lines(in vec2 pos, float angle, float b){
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float scale = 10.0;
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pos *= scale;
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pos = rotate2d( angle ) * pos;
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return smoothstep(0.0,
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.5+b*.5,
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abs((sin(pos.x*3.1415)+b*2.0))*.5);
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}
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void main() {
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vec2 st = gl_FragCoord.xy/u_resolution.xy;
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st.y *= u_resolution.y/u_resolution.x;
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vec2 pos = st.yx*vec2(10.,3.);
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float pattern = pos.x;
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// Stripes
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pattern = lines(pos, 0.0, 0.5 );
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// Add noise
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pattern = lines(pos, noise(pos), .5 );
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gl_FragColor = vec4(vec3(pattern),1.0);
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} |