2 // GLSL textureless classic 3D noise "cnoise",
3 // with an RSL-style periodic variant "pnoise".
4 // Author: Stefan Gustavson (stefan.gustavson@liu.se)
7 // Many thanks to Ian McEwan of Ashima Arts for the
8 // ideas for permutation and gradient selection.
10 // Copyright (c) 2011 Stefan Gustavson. All rights reserved.
11 // Distributed under the MIT license. See LICENSE file.
12 // https://github.com/ashima/webgl-noise
17 return x - floor(x * (1.0 / 289.0)) * 289.0;
22 return x - floor(x * (1.0 / 289.0)) * 289.0;
27 return mod289(((x*34.0)+1.0)*x);
30 vec4 taylorInvSqrt(vec4 r)
32 return 1.79284291400159 - 0.85373472095314 * r;
36 return t*t*t*(t*(t*6.0-15.0)+10.0);
39 // Classic Perlin noise, periodic variant
40 float pnoise(vec3 P, vec3 rep)
42 vec3 Pi0 = mod(floor(P), rep); // Integer part, modulo period
43 vec3 Pi1 = mod(Pi0 + vec3(1.0), rep); // Integer part + 1, mod period
46 vec3 Pf0 = fract(P); // Fractional part for interpolation
47 vec3 Pf1 = Pf0 - vec3(1.0); // Fractional part - 1.0
48 vec4 ix = vec4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
49 vec4 iy = vec4(Pi0.yy, Pi1.yy);
53 vec4 ixy = permute(permute(ix) + iy);
54 vec4 ixy0 = permute(ixy + iz0);
55 vec4 ixy1 = permute(ixy + iz1);
57 vec4 gx0 = ixy0 * (1.0 / 7.0);
58 vec4 gy0 = fract(floor(gx0) * (1.0 / 7.0)) - 0.5;
60 vec4 gz0 = vec4(0.5) - abs(gx0) - abs(gy0);
61 vec4 sz0 = step(gz0, vec4(0.0));
62 gx0 -= sz0 * (step(0.0, gx0) - 0.5);
63 gy0 -= sz0 * (step(0.0, gy0) - 0.5);
65 vec4 gx1 = ixy1 * (1.0 / 7.0);
66 vec4 gy1 = fract(floor(gx1) * (1.0 / 7.0)) - 0.5;
68 vec4 gz1 = vec4(0.5) - abs(gx1) - abs(gy1);
69 vec4 sz1 = step(gz1, vec4(0.0));
70 gx1 -= sz1 * (step(0.0, gx1) - 0.5);
71 gy1 -= sz1 * (step(0.0, gy1) - 0.5);
73 vec3 g000 = vec3(gx0.x,gy0.x,gz0.x);
74 vec3 g100 = vec3(gx0.y,gy0.y,gz0.y);
75 vec3 g010 = vec3(gx0.z,gy0.z,gz0.z);
76 vec3 g110 = vec3(gx0.w,gy0.w,gz0.w);
77 vec3 g001 = vec3(gx1.x,gy1.x,gz1.x);
78 vec3 g101 = vec3(gx1.y,gy1.y,gz1.y);
79 vec3 g011 = vec3(gx1.z,gy1.z,gz1.z);
80 vec3 g111 = vec3(gx1.w,gy1.w,gz1.w);
82 vec4 norm0 = taylorInvSqrt(vec4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
87 vec4 norm1 = taylorInvSqrt(vec4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
93 float n000 = dot(g000, Pf0);
94 float n100 = dot(g100, vec3(Pf1.x, Pf0.yz));
95 float n010 = dot(g010, vec3(Pf0.x, Pf1.y, Pf0.z));
96 float n110 = dot(g110, vec3(Pf1.xy, Pf0.z));
97 float n001 = dot(g001, vec3(Pf0.xy, Pf1.z));
98 float n101 = dot(g101, vec3(Pf1.x, Pf0.y, Pf1.z));
99 float n011 = dot(g011, vec3(Pf0.x, Pf1.yz));
100 float n111 = dot(g111, Pf1);
102 vec3 fade_xyz = fade(Pf0);
103 vec4 n_z = mix(vec4(n000, n100, n010, n110), vec4(n001, n101, n011, n111), fade_xyz.z);
104 vec2 n_yz = mix(n_z.xy, n_z.zw, fade_xyz.y);
105 float n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x);
109 #pragma glslify: export(pnoise)