You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
48 lines
2.1 KiB
48 lines
2.1 KiB
// Cellular noise ("Worley noise") in 2D in GLSL. |
|
// Copyright (c) Stefan Gustavson 2011-04-19. All rights reserved. |
|
// This code is released under the conditions of the MIT license. |
|
// See LICENSE file for details. |
|
// https://github.com/stegu/webgl-noise |
|
|
|
using static Unity.Mathematics.math; |
|
|
|
namespace Unity.Mathematics |
|
{ |
|
public static partial class noise |
|
{ |
|
/// <summary> |
|
/// 2D Cellular noise ("Worley noise") with a 2x2 search window. |
|
/// </summary> |
|
/// <remarks> |
|
/// 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. |
|
/// </remarks> |
|
/// <param name="P">A point in 2D space.</param> |
|
/// <returns>Feature points. F1 is in the x component, F2 in the y component.</returns> |
|
public static float2 cellular2x2(float2 P) |
|
{ |
|
const float K = 0.142857142857f; // 1/7 |
|
const float K2 = 0.0714285714285f; // K/2 |
|
const float jitter = 0.8f; // jitter 1.0 makes F1 wrong more often |
|
|
|
float2 Pi = mod289(floor(P)); |
|
float2 Pf = frac(P); |
|
float4 Pfx = Pf.x + float4(-0.5f, -1.5f, -0.5f, -1.5f); |
|
float4 Pfy = Pf.y + float4(-0.5f, -0.5f, -1.5f, -1.5f); |
|
float4 p = permute(Pi.x + float4(0.0f, 1.0f, 0.0f, 1.0f)); |
|
p = permute(p + Pi.y + float4(0.0f, 0.0f, 1.0f, 1.0f)); |
|
float4 ox = mod7(p) * K + K2; |
|
float4 oy = mod7(floor(p * K)) * K + K2; |
|
float4 dx = Pfx + jitter * ox; |
|
float4 dy = Pfy + jitter * oy; |
|
float4 d = dx * dx + dy * dy; // d11, d12, d21 and d22, squared |
|
// Sort out the two smallest distances |
|
// Do it right and find both F1 and F2 |
|
d.xy = (d.x < d.y) ? d.xy : d.yx; // Swap if smaller |
|
d.xz = (d.x < d.z) ? d.xz : d.zx; |
|
d.xw = (d.x < d.w) ? d.xw : d.wx; |
|
d.y = min(d.y, d.z); |
|
d.y = min(d.y, d.w); |
|
return sqrt(d.xy); |
|
} |
|
} |
|
}
|
|
|