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93 lines
2.7 KiB
93 lines
2.7 KiB
#ifndef __NOISE_3D__
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#define __NOISE_3D__
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#include "noiseMath.cginc"
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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 : stegu
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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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// https://github.com/stegu/webgl-noise
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//
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float snoise(float3 v)
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{
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const float2 C = float2(1.0/6.0, 1.0/3.0) ;
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const float4 D = float4(0.0, 0.5, 1.0, 2.0);
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// First corner
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float3 i = floor(v + dot(v, C.yyy) );
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float3 x0 = v - i + dot(i, C.xxx) ;
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// Other corners
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float3 g = step(x0.yzx, x0.xyz);
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float3 l = 1.0 - g;
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float3 i1 = min( g.xyz, l.zxy );
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float3 i2 = max( g.xyz, l.zxy );
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// x0 = x0 - 0.0 + 0.0 * C.xxx;
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// x1 = x0 - i1 + 1.0 * C.xxx;
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// x2 = x0 - i2 + 2.0 * C.xxx;
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// x3 = x0 - 1.0 + 3.0 * C.xxx;
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float3 x1 = x0 - i1 + C.xxx;
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float3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
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float3 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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float4 p = permute( permute( permute(
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i.z + float4(0.0, i1.z, i2.z, 1.0 ))
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+ i.y + float4(0.0, i1.y, i2.y, 1.0 ))
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+ i.x + float4(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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float3 ns = n_ * D.wyz - D.xzx;
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float4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7)
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float4 x_ = floor(j * ns.z);
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float4 y_ = floor(j - 7.0 * x_ ); // mod(j,N)
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float4 x = x_ *ns.x + ns.yyyy;
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float4 y = y_ *ns.x + ns.yyyy;
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float4 h = 1.0 - abs(x) - abs(y);
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float4 b0 = float4( x.xy, y.xy );
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float4 b1 = float4( x.zw, y.zw );
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//float4 s0 = float4(lessThan(b0,0.0))*2.0 - 1.0;
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//float4 s1 = float4(lessThan(b1,0.0))*2.0 - 1.0;
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float4 s0 = floor(b0)*2.0 + 1.0;
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float4 s1 = floor(b1)*2.0 + 1.0;
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float4 sh = -step(h, float4(0.0));
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float4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
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float4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;
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float3 p0 = float3(a0.xy,h.x);
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float3 p1 = float3(a0.zw,h.y);
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float3 p2 = float3(a1.xy,h.z);
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float3 p3 = float3(a1.zw,h.w);
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//Normalise gradients
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float4 norm = taylorInvSqrt(float4(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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float4 m = max(0.6 - float4(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, float4( dot(p0,x0), dot(p1,x1),
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dot(p2,x2), dot(p3,x3) ) );
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}
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#endif |