rimworld-animation-studio/Library/PackageCache/com.unity.mathematics@1.1.0/Unity.Mathematics/Noise/classicnoise2D.cs
2022-09-13 00:36:34 -05:00

102 lines
3.6 KiB
C#

//
// GLSL textureless classic 2D noise "cnoise",
// with an RSL-style periodic variant "pnoise".
// Author: Stefan Gustavson (stefan.gustavson@liu.se)
// Version: 2011-08-22
//
// Many thanks to Ian McEwan of Ashima Arts for the
// ideas for permutation and gradient selection.
//
// Copyright (c) 2011 Stefan Gustavson. All rights reserved.
// Distributed under the MIT license. See LICENSE file.
// https://github.com/stegu/webgl-noise
//
using static Unity.Mathematics.math;
namespace Unity.Mathematics
{
public static partial class noise
{
// Classic Perlin noise
public static float cnoise(float2 P)
{
float4 Pi = floor(P.xyxy) + float4(0.0f, 0.0f, 1.0f, 1.0f);
float4 Pf = frac(P.xyxy) - float4(0.0f, 0.0f, 1.0f, 1.0f);
Pi = mod289(Pi); // To avoid truncation effects in permutation
float4 ix = Pi.xzxz;
float4 iy = Pi.yyww;
float4 fx = Pf.xzxz;
float4 fy = Pf.yyww;
float4 i = permute(permute(ix) + iy);
float4 gx = frac(i * (1.0f / 41.0f)) * 2.0f - 1.0f;
float4 gy = abs(gx) - 0.5f;
float4 tx = floor(gx + 0.5f);
gx = gx - tx;
float2 g00 = float2(gx.x, gy.x);
float2 g10 = float2(gx.y, gy.y);
float2 g01 = float2(gx.z, gy.z);
float2 g11 = float2(gx.w, gy.w);
float4 norm = taylorInvSqrt(float4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
g00 *= norm.x;
g01 *= norm.y;
g10 *= norm.z;
g11 *= norm.w;
float n00 = dot(g00, float2(fx.x, fy.x));
float n10 = dot(g10, float2(fx.y, fy.y));
float n01 = dot(g01, float2(fx.z, fy.z));
float n11 = dot(g11, float2(fx.w, fy.w));
float2 fade_xy = fade(Pf.xy);
float2 n_x = lerp(float2(n00, n01), float2(n10, n11), fade_xy.x);
float n_xy = lerp(n_x.x, n_x.y, fade_xy.y);
return 2.3f * n_xy;
}
// Classic Perlin noise, periodic variant
public static float pnoise(float2 P, float2 rep)
{
float4 Pi = floor(P.xyxy) + float4(0.0f, 0.0f, 1.0f, 1.0f);
float4 Pf = frac(P.xyxy) - float4(0.0f, 0.0f, 1.0f, 1.0f);
Pi = fmod(Pi, rep.xyxy); // To create noise with explicit period
Pi = mod289(Pi); // To avoid truncation effects in permutation
float4 ix = Pi.xzxz;
float4 iy = Pi.yyww;
float4 fx = Pf.xzxz;
float4 fy = Pf.yyww;
float4 i = permute(permute(ix) + iy);
float4 gx = frac(i * (1.0f / 41.0f)) * 2.0f - 1.0f;
float4 gy = abs(gx) - 0.5f;
float4 tx = floor(gx + 0.5f);
gx = gx - tx;
float2 g00 = float2(gx.x, gy.x);
float2 g10 = float2(gx.y, gy.y);
float2 g01 = float2(gx.z, gy.z);
float2 g11 = float2(gx.w, gy.w);
float4 norm = taylorInvSqrt(float4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
g00 *= norm.x;
g01 *= norm.y;
g10 *= norm.z;
g11 *= norm.w;
float n00 = dot(g00, float2(fx.x, fy.x));
float n10 = dot(g10, float2(fx.y, fy.y));
float n01 = dot(g01, float2(fx.z, fy.z));
float n11 = dot(g11, float2(fx.w, fy.w));
float2 fade_xy = fade(Pf.xy);
float2 n_x = lerp(float2(n00, n01), float2(n10, n11), fade_xy.x);
float n_xy = lerp(n_x.x, n_x.y, fade_xy.y);
return 2.3f * n_xy;
}
}
}