mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-08 01:10:27 +00:00
117 lines
3.3 KiB
GLSL
117 lines
3.3 KiB
GLSL
#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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//
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// GLSL textureless classic 2D noise "cnoise",
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// with an RSL-style periodic variant "pnoise".
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// Author: Stefan Gustavson (stefan.gustavson@liu.se)
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// Version: 2011-08-22
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//
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// Many thanks to Ian McEwan of Ashima Arts for the
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// ideas for permutation and gradient selection.
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//
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// Copyright (c) 2011 Stefan Gustavson. All rights reserved.
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// Distributed under the MIT license. See LICENSE file.
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// https://github.com/ashima/webgl-noise
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//
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vec4 mod289(vec4 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
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vec4 permute(vec4 x) { return mod289(((x*34.0)+1.0)*x); }
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vec4 taylorInvSqrt(vec4 r) { return 1.79284291400159 - 0.85373472095314 * r; }
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vec2 fade(vec2 t) { return t*t*t*(t*(t*6.0-15.0)+10.0); }
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// Classic Perlin noise
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float cnoise(vec2 P) {
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vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
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vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
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Pi = mod289(Pi); // To avoid truncation effects in permutation
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vec4 ix = Pi.xzxz;
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vec4 iy = Pi.yyww;
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vec4 fx = Pf.xzxz;
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vec4 fy = Pf.yyww;
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vec4 i = permute(permute(ix) + iy);
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vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
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vec4 gy = abs(gx) - 0.5 ;
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vec4 tx = floor(gx + 0.5);
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gx = gx - tx;
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vec2 g00 = vec2(gx.x,gy.x);
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vec2 g10 = vec2(gx.y,gy.y);
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vec2 g01 = vec2(gx.z,gy.z);
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vec2 g11 = vec2(gx.w,gy.w);
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vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
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g00 *= norm.x;
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g01 *= norm.y;
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g10 *= norm.z;
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g11 *= norm.w;
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float n00 = dot(g00, vec2(fx.x, fy.x));
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float n10 = dot(g10, vec2(fx.y, fy.y));
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float n01 = dot(g01, vec2(fx.z, fy.z));
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float n11 = dot(g11, vec2(fx.w, fy.w));
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vec2 fade_xy = fade(Pf.xy);
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vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
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float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
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return 2.3 * n_xy;
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}
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// Classic Perlin noise, periodic variant
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float pnoise(vec2 P, vec2 rep) {
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vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
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vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
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Pi = mod(Pi, rep.xyxy); // To create noise with explicit period
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Pi = mod289(Pi); // To avoid truncation effects in permutation
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vec4 ix = Pi.xzxz;
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vec4 iy = Pi.yyww;
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vec4 fx = Pf.xzxz;
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vec4 fy = Pf.yyww;
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vec4 i = permute(permute(ix) + iy);
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vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
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vec4 gy = abs(gx) - 0.5 ;
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vec4 tx = floor(gx + 0.5);
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gx = gx - tx;
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vec2 g00 = vec2(gx.x,gy.x);
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vec2 g10 = vec2(gx.y,gy.y);
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vec2 g01 = vec2(gx.z,gy.z);
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vec2 g11 = vec2(gx.w,gy.w);
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vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
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g00 *= norm.x;
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g01 *= norm.y;
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g10 *= norm.z;
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g11 *= norm.w;
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float n00 = dot(g00, vec2(fx.x, fy.x));
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float n10 = dot(g10, vec2(fx.y, fy.y));
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float n01 = dot(g01, vec2(fx.z, fy.z));
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float n11 = dot(g11, vec2(fx.w, fy.w));
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vec2 fade_xy = fade(Pf.xy);
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vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
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float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
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return 2.3 * n_xy;
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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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vec3 color = vec3(0.0);
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vec2 pos = vec2(st*10.);
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color = vec3( cnoise(pos) );
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gl_FragColor = vec4(color,1.0);
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}
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