265 lines
8.2 KiB
C#
265 lines
8.2 KiB
C#
/*
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* Copyright (c) Contributors, http://opensimulator.org/
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* See CONTRIBUTORS.TXT for a full list of copyright holders.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the OpenSimulator Project nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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using System;
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using OpenMetaverse;
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namespace OpenSim.Region.CoreModules.World.Warp3DMap
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{
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public static class Perlin
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{
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// We use a hardcoded seed to keep the noise generation consistent between runs
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private const int SEED = 42;
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private const int SAMPLE_SIZE = 1024;
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private const int B = SAMPLE_SIZE;
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private const int BM = SAMPLE_SIZE - 1;
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private const int N = 0x1000;
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private static readonly int[] p = new int[SAMPLE_SIZE + SAMPLE_SIZE + 2];
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private static readonly float[,] g3 = new float[SAMPLE_SIZE + SAMPLE_SIZE + 2, 3];
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private static readonly float[,] g2 = new float[SAMPLE_SIZE + SAMPLE_SIZE + 2, 2];
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private static readonly float[] g1 = new float[SAMPLE_SIZE + SAMPLE_SIZE + 2];
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static Perlin()
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{
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Random rng = new Random(SEED);
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int i, j, k;
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for (i = 0; i < B; i++)
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{
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p[i] = i;
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g1[i] = (float)((rng.Next() % (B + B)) - B) / B;
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for (j = 0; j < 2; j++)
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g2[i, j] = (float)((rng.Next() % (B + B)) - B) / B;
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normalize2(g2, i);
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for (j = 0; j < 3; j++)
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g3[i, j] = (float)((rng.Next() % (B + B)) - B) / B;
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normalize3(g3, i);
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}
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while (--i > 0)
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{
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k = p[i];
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p[i] = p[j = rng.Next() % B];
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p[j] = k;
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}
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for (i = 0; i < B + 2; i++)
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{
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p[B + i] = p[i];
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g1[B + i] = g1[i];
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for (j = 0; j < 2; j++)
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g2[B + i, j] = g2[i, j];
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for (j = 0; j < 3; j++)
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g3[B + i, j] = g3[i, j];
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}
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}
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public static float noise1(float arg)
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{
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int bx0, bx1;
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float rx0, rx1, sx, t, u, v;
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t = arg + N;
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bx0 = ((int)t) & BM;
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bx1 = (bx0 + 1) & BM;
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rx0 = t - (int)t;
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rx1 = rx0 - 1f;
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sx = s_curve(rx0);
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u = rx0 * g1[p[bx0]];
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v = rx1 * g1[p[bx1]];
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return Utils.Lerp(u, v, sx);
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}
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public static float noise2(float x, float y)
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{
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int bx, by, b00, b10, b01, b11;
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float rx0, rx1, ry0, ry1, sx, sy, a, b, t, u, v;
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int i, j;
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t = x + N;
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rx0 = t - (int)t;
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bx = ((int)t) & BM;
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i = p[bx];
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bx = (bx + 1) & BM;
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j = p[bx];
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t = y + N;
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ry0 = t - (int)t;
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by = ((int)t) & BM;
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b00 = p[i + by];
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b10 = p[j + by];
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by = (by + 1) & BM;
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b01 = p[i + by];
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b11 = p[j + by];
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sx = s_curve(rx0);
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u = rx0 * g2[b00, 0] + ry0 * g2[b00, 1];
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rx1 = rx0 - 1f;
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v = rx1 * g2[b10, 0] + ry0 * g2[b10, 1];
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a = Utils.Lerp(u, v, sx);
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ry1 = ry0 - 1f;
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u = rx0 * g2[b01, 0] + ry1 * g2[b01, 1];
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v = rx1 * g2[b11, 0] + ry1 * g2[b11, 1];
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b = Utils.Lerp(u, v, sx);
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sy = s_curve(ry0);
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return Utils.Lerp(a, b, sy);
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}
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public static float noise3(float x, float y, float z)
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{
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int bx0, bx1, by0, by1, bz0, bz1, b00, b10, b01, b11;
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float rx0, rx1, ry0, ry1, rz0, rz1, sy, sz, a, b, c, d, t, u, v;
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int i, j;
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t = x + N;
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bx0 = ((int)t) & BM;
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bx1 = (bx0 + 1) & BM;
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rx0 = t - (int)t;
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rx1 = rx0 - 1f;
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t = y + N;
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by0 = ((int)t) & BM;
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by1 = (by0 + 1) & BM;
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ry0 = t - (int)t;
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ry1 = ry0 - 1f;
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t = z + N;
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bz0 = ((int)t) & BM;
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bz1 = (bz0 + 1) & BM;
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rz0 = t - (int)t;
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rz1 = rz0 - 1f;
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i = p[bx0];
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j = p[bx1];
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b00 = p[i + by0];
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b10 = p[j + by0];
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b01 = p[i + by1];
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b11 = p[j + by1];
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t = s_curve(rx0);
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sy = s_curve(ry0);
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sz = s_curve(rz0);
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u = rx0 * g3[b00 + bz0, 0] + ry0 * g3[b00 + bz0, 1] + rz0 * g3[b00 + bz0, 2];
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v = rx1 * g3[b10 + bz0, 0] + ry0 * g3[b10 + bz0, 1] + rz0 * g3[b10 + bz0, 2];
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a = Utils.Lerp(u, v, t);
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u = rx0 * g3[b01 + bz0, 0] + ry1 * g3[b01 + bz0, 1] + rz0 * g3[b01 + bz0, 2];
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v = rx1 * g3[b11 + bz0, 0] + ry1 * g3[b11 + bz0, 1] + rz0 * g3[b11 + bz0, 2];
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b = Utils.Lerp(u, v, t);
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c = Utils.Lerp(a, b, sy);
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u = rx0 * g3[b00 + bz1, 0] + ry0 * g3[b00 + bz1, 1] + rz1 * g3[b00 + bz1, 2];
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v = rx1 * g3[b10 + bz1, 0] + ry0 * g3[b10 + bz1, 1] + rz1 * g3[b10 + bz1, 2];
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a = Utils.Lerp(u, v, t);
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u = rx0 * g3[b01 + bz1, 0] + ry1 * g3[b01 + bz1, 1] + rz1 * g3[b01 + bz1, 2];
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v = rx1 * g3[b11 + bz1, 0] + ry1 * g3[b11 + bz1, 1] + rz1 * g3[b11 + bz1, 2];
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b = Utils.Lerp(u, v, t);
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d = Utils.Lerp(a, b, sy);
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return Utils.Lerp(c, d, sz);
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}
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public static float turbulence1(float x, float freq)
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{
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float t;
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for (t = 0f; freq >= 1f; freq *= 0.5f)
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{
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t += noise1(freq * x) / freq;
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}
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return t;
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}
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public static float turbulence2(float x, float y, float freq)
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{
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float t;
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for (t = 0f; freq >= 1f; freq *= 0.5f)
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t += noise2(freq * x, freq * y) / freq;
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return t;
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}
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public static float turbulence3(float x, float y, float z, float freq)
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{
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float t;
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for (t = 0f; freq >= 1f; freq *= 0.5f)
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{
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t += noise3(freq * x, freq * y, freq * z) / freq;
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}
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return t;
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}
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private static void normalize2(float[,] v, int i)
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{
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float s;
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float a = v[i, 0];
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float b = v[i, 1];
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s = (float)Math.Sqrt(a * a + b * b);
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s = 1.0f / s;
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v[i, 0] = a * s;
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v[i, 1] = b * s;
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}
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private static void normalize3(float[,] v, int i)
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{
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float s;
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float a = v[i, 0];
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float b = v[i, 1];
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float c = v[i, 2];
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s = (float)Math.Sqrt(a * a + b * b + c * c);
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s = 1.0f / s;
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v[i, 0] = a * s;
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v[i, 1] = b * s;
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v[i, 2] = c * s;
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}
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private static float s_curve(float t)
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{
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return t * t * (3f - 2f * t);
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}
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}
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}
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