tacstudios.tngl.sh
A game about forced loneliness, made by TACStudios
1// Cellular noise ("Worley noise") in 2D in GLSL.
2// Copyright (c) Stefan Gustavson 2011-04-19. All rights reserved.
3// This code is released under the conditions of the MIT license.
4// See LICENSE file for details.
5// https://github.com/stegu/webgl-noise
6
7using static Unity.Mathematics.math;
8
9namespace Unity.Mathematics
10{
11 public static partial class noise
12 {
13 /// <summary>
14 /// 2D Cellular noise ("Worley noise") with a 2x2 search window.
15 /// </summary>
16 /// <remarks>
17 /// Faster than using 3x3, at the expense of some strong pattern artifacts. F2 is often wrong and has sharp discontinuities. If you need a smooth F2, use the slower 3x3 version. F1 is sometimes wrong, too, but OK for most purposes.
18 /// </remarks>
19 /// <param name="P">A point in 2D space.</param>
20 /// <returns>Feature points. F1 is in the x component, F2 in the y component.</returns>
21 public static float2 cellular2x2(float2 P)
22 {
23 const float K = 0.142857142857f; // 1/7
24 const float K2 = 0.0714285714285f; // K/2
25 const float jitter = 0.8f; // jitter 1.0 makes F1 wrong more often
26
27 float2 Pi = mod289(floor(P));
28 float2 Pf = frac(P);
29 float4 Pfx = Pf.x + float4(-0.5f, -1.5f, -0.5f, -1.5f);
30 float4 Pfy = Pf.y + float4(-0.5f, -0.5f, -1.5f, -1.5f);
31 float4 p = permute(Pi.x + float4(0.0f, 1.0f, 0.0f, 1.0f));
32 p = permute(p + Pi.y + float4(0.0f, 0.0f, 1.0f, 1.0f));
33 float4 ox = mod7(p) * K + K2;
34 float4 oy = mod7(floor(p * K)) * K + K2;
35 float4 dx = Pfx + jitter * ox;
36 float4 dy = Pfy + jitter * oy;
37 float4 d = dx * dx + dy * dy; // d11, d12, d21 and d22, squared
38 // Sort out the two smallest distances
39 // Do it right and find both F1 and F2
40 d.xy = (d.x < d.y) ? d.xy : d.yx; // Swap if smaller
41 d.xz = (d.x < d.z) ? d.xz : d.zx;
42 d.xw = (d.x < d.w) ? d.xw : d.wx;
43 d.y = min(d.y, d.z);
44 d.y = min(d.y, d.w);
45 return sqrt(d.xy);
46 }
47 }
48}