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