opensim – Blame information for rev 1
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1 | eva | 1 | /* |
2 | * Copyright (c) Contributors, http://opensimulator.org/ |
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3 | * See CONTRIBUTORS.TXT for a full list of copyright holders. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions are met: |
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7 | * * Redistributions of source code must retain the above copyright |
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8 | * notice, this list of conditions and the following disclaimer. |
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9 | * * Redistributions in binary form must reproduce the above copyright |
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10 | * notice, this list of conditions and the following disclaimer in the |
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11 | * documentation and/or other materials provided with the distribution. |
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12 | * * Neither the name of the OpenSimulator Project nor the |
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13 | * names of its contributors may be used to endorse or promote products |
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14 | * derived from this software without specific prior written permission. |
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15 | * |
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16 | * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY |
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17 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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18 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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19 | * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY |
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20 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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21 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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22 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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23 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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25 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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26 | */ |
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27 | |||
28 | using System; |
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29 | using OpenSim.Region.Framework.Interfaces; |
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30 | |||
31 | namespace OpenSim.Region.Framework.Scenes |
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32 | { |
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33 | public static class TerrainUtil |
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34 | { |
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35 | public static double MetersToSphericalStrength(double size) |
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36 | { |
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37 | //return Math.Pow(2, size); |
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38 | return (size + 1) * 1.35; // MCP: a more useful brush size range |
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39 | } |
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40 | |||
41 | public static double SphericalFactor(double x, double y, double rx, double ry, double size) |
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42 | { |
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43 | return size * size - ((x - rx) * (x - rx) + (y - ry) * (y - ry)); |
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44 | } |
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45 | |||
46 | public static double GetBilinearInterpolate(double x, double y, ITerrainChannel map) |
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47 | { |
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48 | int w = map.Width; |
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49 | int h = map.Height; |
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50 | |||
51 | if (x > w - 2.0) |
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52 | x = w - 2.0; |
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53 | if (y > h - 2.0) |
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54 | y = h - 2.0; |
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55 | if (x < 0.0) |
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56 | x = 0.0; |
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57 | if (y < 0.0) |
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58 | y = 0.0; |
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59 | |||
60 | const int stepSize = 1; |
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61 | double h00 = map[(int) x, (int) y]; |
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62 | double h10 = map[(int) x + stepSize, (int) y]; |
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63 | double h01 = map[(int) x, (int) y + stepSize]; |
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64 | double h11 = map[(int) x + stepSize, (int) y + stepSize]; |
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65 | double h1 = h00; |
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66 | double h2 = h10; |
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67 | double h3 = h01; |
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68 | double h4 = h11; |
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69 | double a00 = h1; |
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70 | double a10 = h2 - h1; |
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71 | double a01 = h3 - h1; |
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72 | double a11 = h1 - h2 - h3 + h4; |
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73 | double partialx = x - (int) x; |
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74 | double partialz = y - (int) y; |
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75 | double hi = a00 + (a10 * partialx) + (a01 * partialz) + (a11 * partialx * partialz); |
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76 | return hi; |
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77 | } |
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78 | |||
79 | private static double Noise(double x, double y) |
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80 | { |
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81 | int n = (int) x + (int) (y * 749); |
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82 | n = (n << 13) ^ n; |
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83 | return (1.0 - ((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0); |
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84 | } |
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85 | |||
86 | private static double SmoothedNoise1(double x, double y) |
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87 | { |
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88 | double corners = (Noise(x - 1, y - 1) + Noise(x + 1, y - 1) + Noise(x - 1, y + 1) + Noise(x + 1, y + 1)) / 16; |
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89 | double sides = (Noise(x - 1, y) + Noise(x + 1, y) + Noise(x, y - 1) + Noise(x, y + 1)) / 8; |
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90 | double center = Noise(x, y) / 4; |
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91 | return corners + sides + center; |
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92 | } |
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93 | |||
94 | private static double Interpolate(double x, double y, double z) |
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95 | { |
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96 | return (x * (1.0 - z)) + (y * z); |
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97 | } |
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98 | |||
99 | public static double InterpolatedNoise(double x, double y) |
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100 | { |
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101 | int integer_X = (int) (x); |
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102 | double fractional_X = x - integer_X; |
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103 | |||
104 | int integer_Y = (int) y; |
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105 | double fractional_Y = y - integer_Y; |
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106 | |||
107 | double v1 = SmoothedNoise1(integer_X, integer_Y); |
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108 | double v2 = SmoothedNoise1(integer_X + 1, integer_Y); |
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109 | double v3 = SmoothedNoise1(integer_X, integer_Y + 1); |
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110 | double v4 = SmoothedNoise1(integer_X + 1, integer_Y + 1); |
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111 | |||
112 | double i1 = Interpolate(v1, v2, fractional_X); |
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113 | double i2 = Interpolate(v3, v4, fractional_X); |
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114 | |||
115 | return Interpolate(i1, i2, fractional_Y); |
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116 | } |
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117 | |||
118 | public static double PerlinNoise2D(double x, double y, int octaves, double persistence) |
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119 | { |
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120 | double total = 0.0; |
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121 | |||
122 | for (int i = 0; i < octaves; i++) |
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123 | { |
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124 | double frequency = Math.Pow(2, i); |
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125 | double amplitude = Math.Pow(persistence, i); |
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126 | |||
127 | total += InterpolatedNoise(x * frequency, y * frequency) * amplitude; |
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128 | } |
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129 | return total; |
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130 | } |
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131 | } |
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132 | } |