162 lines
6.7 KiB
C#
162 lines
6.7 KiB
C#
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//
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// GLSL textureless classic 3D 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: 2011-10-11
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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/stegu/webgl-noise
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//
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using static Unity.Mathematics.math;
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namespace Unity.Mathematics
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{
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public static partial class noise
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{
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// Classic Perlin noise
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public static float cnoise(float3 P)
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{
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float3 Pi0 = floor(P); // Integer part for indexing
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float3 Pi1 = Pi0 + float3(1.0f); // Integer part + 1
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Pi0 = mod289(Pi0);
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Pi1 = mod289(Pi1);
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float3 Pf0 = frac(P); // Fractional part for interpolation
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float3 Pf1 = Pf0 - float3(1.0f); // Fractional part - 1.0
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float4 ix = float4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
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float4 iy = float4(Pi0.yy, Pi1.yy);
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float4 iz0 = Pi0.zzzz;
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float4 iz1 = Pi1.zzzz;
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float4 ixy = permute(permute(ix) + iy);
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float4 ixy0 = permute(ixy + iz0);
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float4 ixy1 = permute(ixy + iz1);
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float4 gx0 = ixy0 * (1.0f / 7.0f);
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float4 gy0 = frac(floor(gx0) * (1.0f / 7.0f)) - 0.5f;
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gx0 = frac(gx0);
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float4 gz0 = float4(0.5f) - abs(gx0) - abs(gy0);
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float4 sz0 = step(gz0, float4(0.0f));
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gx0 -= sz0 * (step(0.0f, gx0) - 0.5f);
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gy0 -= sz0 * (step(0.0f, gy0) - 0.5f);
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float4 gx1 = ixy1 * (1.0f / 7.0f);
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float4 gy1 = frac(floor(gx1) * (1.0f / 7.0f)) - 0.5f;
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gx1 = frac(gx1);
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float4 gz1 = float4(0.5f) - abs(gx1) - abs(gy1);
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float4 sz1 = step(gz1, float4(0.0f));
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gx1 -= sz1 * (step(0.0f, gx1) - 0.5f);
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gy1 -= sz1 * (step(0.0f, gy1) - 0.5f);
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float3 g000 = float3(gx0.x, gy0.x, gz0.x);
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float3 g100 = float3(gx0.y, gy0.y, gz0.y);
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float3 g010 = float3(gx0.z, gy0.z, gz0.z);
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float3 g110 = float3(gx0.w, gy0.w, gz0.w);
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float3 g001 = float3(gx1.x, gy1.x, gz1.x);
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float3 g101 = float3(gx1.y, gy1.y, gz1.y);
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float3 g011 = float3(gx1.z, gy1.z, gz1.z);
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float3 g111 = float3(gx1.w, gy1.w, gz1.w);
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float4 norm0 = taylorInvSqrt(float4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
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g000 *= norm0.x;
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g010 *= norm0.y;
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g100 *= norm0.z;
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g110 *= norm0.w;
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float4 norm1 = taylorInvSqrt(float4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
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g001 *= norm1.x;
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g011 *= norm1.y;
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g101 *= norm1.z;
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g111 *= norm1.w;
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float n000 = dot(g000, Pf0);
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float n100 = dot(g100, float3(Pf1.x, Pf0.yz));
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float n010 = dot(g010, float3(Pf0.x, Pf1.y, Pf0.z));
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float n110 = dot(g110, float3(Pf1.xy, Pf0.z));
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float n001 = dot(g001, float3(Pf0.xy, Pf1.z));
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float n101 = dot(g101, float3(Pf1.x, Pf0.y, Pf1.z));
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float n011 = dot(g011, float3(Pf0.x, Pf1.yz));
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float n111 = dot(g111, Pf1);
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float3 fade_xyz = fade(Pf0);
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float4 n_z = lerp(float4(n000, n100, n010, n110), float4(n001, n101, n011, n111), fade_xyz.z);
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float2 n_yz = lerp(n_z.xy, n_z.zw, fade_xyz.y);
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float n_xyz = lerp(n_yz.x, n_yz.y, fade_xyz.x);
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return 2.2f * n_xyz;
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}
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// Classic Perlin noise, periodic variant
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public static float pnoise(float3 P, float3 rep)
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{
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float3 Pi0 = fmod(floor(P), rep); // Integer part, math.modulo period
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float3 Pi1 = fmod(Pi0 + float3(1.0f), rep); // Integer part + 1, math.mod period
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Pi0 = mod289(Pi0);
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Pi1 = mod289(Pi1);
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float3 Pf0 = frac(P); // Fractional part for interpolation
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float3 Pf1 = Pf0 - float3(1.0f); // Fractional part - 1.0
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float4 ix = float4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
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float4 iy = float4(Pi0.yy, Pi1.yy);
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float4 iz0 = Pi0.zzzz;
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float4 iz1 = Pi1.zzzz;
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float4 ixy = permute(permute(ix) + iy);
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float4 ixy0 = permute(ixy + iz0);
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float4 ixy1 = permute(ixy + iz1);
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float4 gx0 = ixy0 * (1.0f / 7.0f);
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float4 gy0 = frac(floor(gx0) * (1.0f / 7.0f)) - 0.5f;
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gx0 = frac(gx0);
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float4 gz0 = float4(0.5f) - abs(gx0) - abs(gy0);
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float4 sz0 = step(gz0, float4(0.0f));
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gx0 -= sz0 * (step(0.0f, gx0) - 0.5f);
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gy0 -= sz0 * (step(0.0f, gy0) - 0.5f);
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float4 gx1 = ixy1 * (1.0f / 7.0f);
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float4 gy1 = frac(floor(gx1) * (1.0f / 7.0f)) - 0.5f;
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gx1 = frac(gx1);
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float4 gz1 = float4(0.5f) - abs(gx1) - abs(gy1);
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float4 sz1 = step(gz1, float4(0.0f));
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gx1 -= sz1 * (step(0.0f, gx1) - 0.5f);
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gy1 -= sz1 * (step(0.0f, gy1) - 0.5f);
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float3 g000 = float3(gx0.x, gy0.x, gz0.x);
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float3 g100 = float3(gx0.y, gy0.y, gz0.y);
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float3 g010 = float3(gx0.z, gy0.z, gz0.z);
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float3 g110 = float3(gx0.w, gy0.w, gz0.w);
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float3 g001 = float3(gx1.x, gy1.x, gz1.x);
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float3 g101 = float3(gx1.y, gy1.y, gz1.y);
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float3 g011 = float3(gx1.z, gy1.z, gz1.z);
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float3 g111 = float3(gx1.w, gy1.w, gz1.w);
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float4 norm0 = taylorInvSqrt(float4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
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g000 *= norm0.x;
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g010 *= norm0.y;
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g100 *= norm0.z;
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g110 *= norm0.w;
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float4 norm1 = taylorInvSqrt(float4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
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g001 *= norm1.x;
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g011 *= norm1.y;
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g101 *= norm1.z;
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g111 *= norm1.w;
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float n000 = dot(g000, Pf0);
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float n100 = dot(g100, float3(Pf1.x, Pf0.yz));
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float n010 = dot(g010, float3(Pf0.x, Pf1.y, Pf0.z));
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float n110 = dot(g110, float3(Pf1.xy, Pf0.z));
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float n001 = dot(g001, float3(Pf0.xy, Pf1.z));
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float n101 = dot(g101, float3(Pf1.x, Pf0.y, Pf1.z));
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float n011 = dot(g011, float3(Pf0.x, Pf1.yz));
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float n111 = dot(g111, Pf1);
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float3 fade_xyz = fade(Pf0);
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float4 n_z = lerp(float4(n000, n100, n010, n110), float4(n001, n101, n011, n111), fade_xyz.z);
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float2 n_yz = lerp(n_z.xy, n_z.zw, fade_xyz.y);
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float n_xyz = lerp(n_yz.x, n_yz.y, fade_xyz.x);
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return 2.2f * n_xyz;
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}
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}
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}
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