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16cad5d Jul 2, 2017
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//
// Noise Shader Library for Unity - https://github.com/keijiro/NoiseShader
//
// Original work (webgl-noise) Copyright (C) 2011 Ashima Arts.
// Translation and modification was made by Keijiro Takahashi.
//
// This shader is based on the webgl-noise GLSL shader. For further details
// of the original shader, please see the following description from the
// original source code.
//
//
// Description : Array and textureless GLSL 2D/3D/4D simplex
// noise functions.
// Author : Ian McEwan, Ashima Arts.
// Maintainer : ijm
// Lastmod : 20110822 (ijm)
// License : Copyright (C) 2011 Ashima Arts. All rights reserved.
// Distributed under the MIT License. See LICENSE file.
// https://github.com/ashima/webgl-noise
//
float3 mod289(float3 x)
{
return x - floor(x / 289.0) * 289.0;
}
float4 mod289(float4 x)
{
return x - floor(x / 289.0) * 289.0;
}
float4 permute(float4 x)
{
return mod289((x * 34.0 + 1.0) * x);
}
float4 taylorInvSqrt(float4 r)
{
return 1.79284291400159 - r * 0.85373472095314;
}
float snoise(float3 v)
{
const float2 C = float2(1.0 / 6.0, 1.0 / 3.0);
// First corner
float3 i = floor(v + dot(v, C.yyy));
float3 x0 = v - i + dot(i, C.xxx);
// Other corners
float3 g = step(x0.yzx, x0.xyz);
float3 l = 1.0 - g;
float3 i1 = min(g.xyz, l.zxy);
float3 i2 = max(g.xyz, l.zxy);
// x1 = x0 - i1 + 1.0 * C.xxx;
// x2 = x0 - i2 + 2.0 * C.xxx;
// x3 = x0 - 1.0 + 3.0 * C.xxx;
float3 x1 = x0 - i1 + C.xxx;
float3 x2 = x0 - i2 + C.yyy;
float3 x3 = x0 - 0.5;
// Permutations
i = mod289(i); // Avoid truncation effects in permutation
float4 p =
permute(permute(permute(i.z + float4(0.0, i1.z, i2.z, 1.0))
+ i.y + float4(0.0, i1.y, i2.y, 1.0))
+ i.x + float4(0.0, i1.x, i2.x, 1.0));
// Gradients: 7x7 points over a square, mapped onto an octahedron.
// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
float4 j = p - 49.0 * floor(p / 49.0); // mod(p,7*7)
float4 x_ = floor(j / 7.0);
float4 y_ = floor(j - 7.0 * x_); // mod(j,N)
float4 x = (x_ * 2.0 + 0.5) / 7.0 - 1.0;
float4 y = (y_ * 2.0 + 0.5) / 7.0 - 1.0;
float4 h = 1.0 - abs(x) - abs(y);
float4 b0 = float4(x.xy, y.xy);
float4 b1 = float4(x.zw, y.zw);
//float4 s0 = float4(lessThan(b0, 0.0)) * 2.0 - 1.0;
//float4 s1 = float4(lessThan(b1, 0.0)) * 2.0 - 1.0;
float4 s0 = floor(b0) * 2.0 + 1.0;
float4 s1 = floor(b1) * 2.0 + 1.0;
float4 sh = -step(h, 0.0);
float4 a0 = b0.xzyw + s0.xzyw * sh.xxyy;
float4 a1 = b1.xzyw + s1.xzyw * sh.zzww;
float3 g0 = float3(a0.xy, h.x);
float3 g1 = float3(a0.zw, h.y);
float3 g2 = float3(a1.xy, h.z);
float3 g3 = float3(a1.zw, h.w);
// Normalise gradients
float4 norm = taylorInvSqrt(float4(dot(g0, g0), dot(g1, g1), dot(g2, g2), dot(g3, g3)));
g0 *= norm.x;
g1 *= norm.y;
g2 *= norm.z;
g3 *= norm.w;
// Mix final noise value
float4 m = max(0.6 - float4(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), 0.0);
m = m * m;
m = m * m;
float4 px = float4(dot(x0, g0), dot(x1, g1), dot(x2, g2), dot(x3, g3));
return 42.0 * dot(m, px);
}
float4 snoise_grad(float3 v)
{
const float2 C = float2(1.0 / 6.0, 1.0 / 3.0);
// First corner
float3 i = floor(v + dot(v, C.yyy));
float3 x0 = v - i + dot(i, C.xxx);
// Other corners
float3 g = step(x0.yzx, x0.xyz);
float3 l = 1.0 - g;
float3 i1 = min(g.xyz, l.zxy);
float3 i2 = max(g.xyz, l.zxy);
// x1 = x0 - i1 + 1.0 * C.xxx;
// x2 = x0 - i2 + 2.0 * C.xxx;
// x3 = x0 - 1.0 + 3.0 * C.xxx;
float3 x1 = x0 - i1 + C.xxx;
float3 x2 = x0 - i2 + C.yyy;
float3 x3 = x0 - 0.5;
// Permutations
i = mod289(i); // Avoid truncation effects in permutation
float4 p =
permute(permute(permute(i.z + float4(0.0, i1.z, i2.z, 1.0))
+ i.y + float4(0.0, i1.y, i2.y, 1.0))
+ i.x + float4(0.0, i1.x, i2.x, 1.0));
// Gradients: 7x7 points over a square, mapped onto an octahedron.
// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
float4 j = p - 49.0 * floor(p / 49.0); // mod(p,7*7)
float4 x_ = floor(j / 7.0);
float4 y_ = floor(j - 7.0 * x_); // mod(j,N)
float4 x = (x_ * 2.0 + 0.5) / 7.0 - 1.0;
float4 y = (y_ * 2.0 + 0.5) / 7.0 - 1.0;
float4 h = 1.0 - abs(x) - abs(y);
float4 b0 = float4(x.xy, y.xy);
float4 b1 = float4(x.zw, y.zw);
//float4 s0 = float4(lessThan(b0, 0.0)) * 2.0 - 1.0;
//float4 s1 = float4(lessThan(b1, 0.0)) * 2.0 - 1.0;
float4 s0 = floor(b0) * 2.0 + 1.0;
float4 s1 = floor(b1) * 2.0 + 1.0;
float4 sh = -step(h, 0.0);
float4 a0 = b0.xzyw + s0.xzyw * sh.xxyy;
float4 a1 = b1.xzyw + s1.xzyw * sh.zzww;
float3 g0 = float3(a0.xy, h.x);
float3 g1 = float3(a0.zw, h.y);
float3 g2 = float3(a1.xy, h.z);
float3 g3 = float3(a1.zw, h.w);
// Normalise gradients
float4 norm = taylorInvSqrt(float4(dot(g0, g0), dot(g1, g1), dot(g2, g2), dot(g3, g3)));
g0 *= norm.x;
g1 *= norm.y;
g2 *= norm.z;
g3 *= norm.w;
// Compute noise and gradient at P
float4 m = max(0.6 - float4(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), 0.0);
float4 m2 = m * m;
float4 m3 = m2 * m;
float4 m4 = m2 * m2;
float3 grad =
-6.0 * m3.x * x0 * dot(x0, g0) + m4.x * g0 +
-6.0 * m3.y * x1 * dot(x1, g1) + m4.y * g1 +
-6.0 * m3.z * x2 * dot(x2, g2) + m4.z * g2 +
-6.0 * m3.w * x3 * dot(x3, g3) + m4.w * g3;
float4 px = float4(dot(x0, g0), dot(x1, g1), dot(x2, g2), dot(x3, g3));
return 42.0 * float4(grad, dot(m4, px));
}