mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
158 lines
4.5 KiB
GLSL
158 lines
4.5 KiB
GLSL
// Author @patriciogv - 2015 - patriciogonzalezvivo.com
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#ifdef GL_OES_standard_derivatives
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#extension GL_OES_standard_derivatives: enable
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#endif
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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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vec2 skew (vec2 st) {
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vec2 r = vec2(0.0);
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r.x = 1.1547*st.x;
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r.y = st.y+0.5*r.x;
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return r;
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}
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vec3 simplexGrid (vec2 st) {
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vec3 xyz = vec3(0.0);
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vec2 p = fract(skew(st));
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if (p.x > p.y) {
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xyz.xy = 1.0-vec2(p.x,p.y-p.x);
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xyz.z = p.y;
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} else {
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xyz.yz = 1.0-vec2(p.x-p.y,p.y);
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xyz.x = p.x;
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// xyz.zx = 1.-vec2(p.x-p.y,p.y);
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// xyz.y = p.x;
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}
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return fract(xyz);
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}
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// Antialiazed Step function
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// from http://webstaff.itn.liu.se/~stegu/webglshadertutorial/shadertutorial.html
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float aastep(float threshold, float value) {
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#ifdef GL_OES_standard_derivatives
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float afwidth = 0.7 * length(vec2(dFdx(value), dFdy(value)));
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return smoothstep(threshold-afwidth, threshold+afwidth, value);
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#else
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return step(threshold, value);
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#endif
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}
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vec2 aastep(float threshold, vec2 value) {
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return vec2(aastep(threshold, value.x),
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aastep(threshold, value.y));
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}
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vec3 aastep(float threshold, vec3 value) {
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return vec3(aastep(threshold, value.x),
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aastep(threshold, value.y),
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aastep(threshold, value.z));
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}
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//
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// Description : Array and textureless GLSL 2D/3D/4D simplex
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// noise functions.
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// Author : Ian McEwan, Ashima Arts.
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// Maintainer : ijm
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// Lastmod : 20110822 (ijm)
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// License : Copyright (C) 2011 Ashima Arts. 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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vec3 mod289(vec3 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
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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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float snoise(vec3 v) {
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const vec2 C = vec2(1.0/6.0, 1.0/3.0) ;
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const vec4 D = vec4(0.0, 0.5, 1.0, 2.0);
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// First corner
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vec3 i = floor(v + dot(v, C.yyy) );
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vec3 x0 = v - i + dot(i, C.xxx) ;
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// Other corners
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vec3 g = step(x0.yzx, x0.xyz);
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vec3 l = 1.0 - g;
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vec3 i1 = min( g.xyz, l.zxy );
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vec3 i2 = max( g.xyz, l.zxy );
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vec3 x1 = x0 - i1 + C.xxx;
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vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
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vec3 x3 = x0 - D.yyy; // -1.0+3.0*C.x = -0.5 = -D.y
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// Permutations
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i = mod289(i);
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vec4 p = permute( permute( permute(
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i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
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+ i.y + vec4(0.0, i1.y, i2.y, 1.0 ))
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+ i.x + vec4(0.0, i1.x, i2.x, 1.0 ));
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// Gradients: 7x7 points over a square, mapped onto an octahedron.
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// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
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float n_ = 0.142857142857; // 1.0/7.0
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vec3 ns = n_ * D.wyz - D.xzx;
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vec4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7)
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vec4 x_ = floor(j * ns.z);
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vec4 y_ = floor(j - 7.0 * x_ ); // mod(j,N)
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vec4 x = x_ *ns.x + ns.yyyy;
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vec4 y = y_ *ns.x + ns.yyyy;
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vec4 h = 1.0 - abs(x) - abs(y);
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vec4 b0 = vec4( x.xy, y.xy );
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vec4 b1 = vec4( x.zw, y.zw );
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vec4 s0 = floor(b0)*2.0 + 1.0;
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vec4 s1 = floor(b1)*2.0 + 1.0;
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vec4 sh = -step(h, vec4(0.0));
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vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
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vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;
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vec3 p0 = vec3(a0.xy,h.x);
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vec3 p1 = vec3(a0.zw,h.y);
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vec3 p2 = vec3(a1.xy,h.z);
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vec3 p3 = vec3(a1.zw,h.w);
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//Normalise gradients
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vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
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p0 *= norm.x;
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p1 *= norm.y;
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p2 *= norm.z;
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p3 *= norm.w;
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// Mix final noise value
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vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
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m = m * m;
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return 42.0 * dot( m*m, vec4(dot(p0,x0), dot(p1,x1),
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dot(p2,x2), dot(p3,x3) ) );
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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.x *= u_resolution.x/u_resolution.y;
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vec3 color = vec3(0.0);
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float t = u_time*.5;
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float pct = clamp((snoise(vec3(st*2.,t))*.5+.5)*.2 + abs(sin(dot(st-.5,st-.5)*3.14-t))*.5,0.,1.);
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st *= 1.733*10.+5.*clamp(abs(sin(dot(st-.5,st-.5)*3.14+t*0.5))*.5,0.2,1.);
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vec3 S = simplexGrid(st);
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S = aastep(abs(sin(pct*3.1415+u_time)),S);
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pct = S.r * S.g * S.b;
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color = vec3(pct);
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gl_FragColor = vec4(color,1.0);
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} |