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67 lines
2.5 KiB
67 lines
2.5 KiB
#ifndef __CELLULAE_2X2X2__
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#define __CELLULAE_2X2X2__
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#include "noiseMath.cginc"
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// Cellular noise ("Worley noise") in 3D in GLSL.
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// Copyright (c) Stefan Gustavson 2011-04-19. All rights reserved.
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// This code is released under the conditions of the MIT license.
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// See LICENSE file for details.
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// https://github.com/stegu/webgl-noise
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// Cellular noise, returning F1 and F2 in a vec2.
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// Speeded up by using 2x2x2 search window instead of 3x3x3,
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// at the expense of some pattern artifacts.
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// F2 is often wrong and has sharp discontinuities.
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// If you need a good F2, use the slower 3x3x3 version.
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float2 cellular2x2x2(float3 P) {
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const float K = 0.142857142857; // 1/7
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const float Ko = 0.428571428571; // 1/2-K/2
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const float K2 = 0.020408163265306; // 1/(7*7)
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const float Kz = 0.166666666667; // 1/6
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const float Kzo = 0.416666666667; // 1/2-1/6*2
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const float jitter = 0.8; // smaller jitter gives less errors in F2
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float3 Pi = mod289(floor(P));
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float3 Pf = fract(P);
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float4 Pfx = Pf.x + vec4(0.0, -1.0, 0.0, -1.0);
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float4 Pfy = Pf.y + vec4(0.0, 0.0, -1.0, -1.0);
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float4 p = permute(Pi.x + vec4(0.0, 1.0, 0.0, 1.0));
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p = permute(p + Pi.y + vec4(0.0, 0.0, 1.0, 1.0));
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float4 p1 = permute(p + Pi.z); // z+0
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float4 p2 = permute(p + Pi.z + vec4(1.0)); // z+1
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float4 ox1 = frac(p1*K) - Ko;
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float4 oy1 = mod7(floor(p1*K))*K - Ko;
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float4 oz1 = floor(p1*K2)*Kz - Kzo; // p1 < 289 guaranteed
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float4 ox2 = fract(p2*K) - Ko;
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float4 oy2 = mod7(floor(p2*K))*K - Ko;
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float4 oz2 = floor(p2*K2)*Kz - Kzo;
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float4 dx1 = Pfx + jitter*ox1;
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float4 dy1 = Pfy + jitter*oy1;
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float4 dz1 = Pf.z + jitter*oz1;
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float4 dx2 = Pfx + jitter*ox2;
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float4 dy2 = Pfy + jitter*oy2;
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float4 dz2 = Pf.z - 1.0 + jitter*oz2;
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float4 d1 = dx1 * dx1 + dy1 * dy1 + dz1 * dz1; // z+0
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float4 d2 = dx2 * dx2 + dy2 * dy2 + dz2 * dz2; // z+1
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// Sort out the two smallest distances (F1, F2)
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#if false
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// Cheat and sort out only F1
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d1 = min(d1, d2);
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d1.xy = min(d1.xy, d1.wz);
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d1.x = min(d1.x, d1.y);
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return vec2(sqrt(d1.x));
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#else
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// Do it right and sort out both F1 and F2
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vec4 d = min(d1,d2); // F1 is now in d
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d2 = max(d1,d2); // Make sure we keep all candidates for F2
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d.xy = (d.x < d.y) ? d.xy : d.yx; // Swap smallest to d.x
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d.xz = (d.x < d.z) ? d.xz : d.zx;
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d.xw = (d.x < d.w) ? d.xw : d.wx; // F1 is now in d.x
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d.yzw = min(d.yzw, d2.yzw); // F2 now not in d2.yzw
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d.y = min(d.y, d.z); // nor in d.z
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d.y = min(d.y, d.w); // nor in d.w
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d.y = min(d.y, d2.x); // F2 is now in d.y
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return sqrt(d.xy); // F1 and F2
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#endif
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}
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