aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/OpenSim/Region/Environment/Modules/Terrain/PaintBrushes/ErodeSphere.cs
blob: cfb1f607467b7fd6f21a2c1ea7e15b39883815da (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
/*
 * 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 OpenSim 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 OpenSim.Region.Environment.Interfaces;

namespace OpenSim.Region.Environment.Modules.Terrain.PaintBrushes
{
    /// <summary>
    /// Hydraulic Erosion Brush
    /// </summary>
    public class ErodeSphere : ITerrainPaintableEffect
    {
        private double rainHeight = 0.2;
        private int rounds = 10;
        private NeighbourSystem type = NeighbourSystem.Moore; // Parameter
        private double waterSaturation = 0.30; // Can carry 1% of water in height

        #region Supporting Functions

        private int[] Neighbours(NeighbourSystem type, int index)
        {
            int[] coord = new int[2];

            index++;

            switch (type)
            {
                case NeighbourSystem.Moore:
                    switch (index)
                    {
                        case 1:
                            coord[0] = -1;
                            coord[1] = -1;
                            break;

                        case 2:
                            coord[0] = -0;
                            coord[1] = -1;
                            break;

                        case 3:
                            coord[0] = +1;
                            coord[1] = -1;
                            break;

                        case 4:
                            coord[0] = -1;
                            coord[1] = -0;
                            break;

                        case 5:
                            coord[0] = -0;
                            coord[1] = -0;
                            break;

                        case 6:
                            coord[0] = +1;
                            coord[1] = -0;
                            break;

                        case 7:
                            coord[0] = -1;
                            coord[1] = +1;
                            break;

                        case 8:
                            coord[0] = -0;
                            coord[1] = +1;
                            break;

                        case 9:
                            coord[0] = +1;
                            coord[1] = +1;
                            break;

                        default:
                            break;
                    }
                    break;

                case NeighbourSystem.VonNeumann:
                    switch (index)
                    {
                        case 1:
                            coord[0] = 0;
                            coord[1] = -1;
                            break;

                        case 2:
                            coord[0] = -1;
                            coord[1] = 0;
                            break;

                        case 3:
                            coord[0] = +1;
                            coord[1] = 0;
                            break;

                        case 4:
                            coord[0] = 0;
                            coord[1] = +1;
                            break;

                        case 5:
                            coord[0] = -0;
                            coord[1] = -0;
                            break;

                        default:
                            break;
                    }
                    break;
            }

            return coord;
        }

        private enum NeighbourSystem
        {
            Moore,
            VonNeumann
        } ;

        #endregion

        #region ITerrainPaintableEffect Members

        public void PaintEffect(ITerrainChannel map, double rx, double ry, double strength, double duration)
        {
            strength = TerrainUtil.MetersToSphericalStrength(strength);

            int x, y;
            // Using one 'rain' round for this, so skipping a useless loop
            // Will need to adapt back in for the Flood brush

            ITerrainChannel water = new TerrainChannel(map.Width, map.Height);
            ITerrainChannel sediment = new TerrainChannel(map.Width, map.Height);

            // Fill with rain
            for (x = 0; x < water.Width; x++)
                for (y = 0; y < water.Height; y++)
                    water[x, y] = Math.Max(0.0, TerrainUtil.SphericalFactor(x, y, rx, ry, strength) * rainHeight * duration);

            for (int i = 0; i < rounds; i++)
            {
                // Erode underlying terrain
                for (x = 0; x < water.Width; x++)
                {
                    for (y = 0; y < water.Height; y++)
                    {
                        double solConst = (1.0 / rounds);
                        double sedDelta = water[x, y] * solConst;
                        map[x, y] -= sedDelta;
                        sediment[x, y] += sedDelta;
                    }
                }

                // Move water
                for (x = 0; x < water.Width; x++)
                {
                    for (y = 0; y < water.Height; y++)
                    {
                        if (water[x, y] <= 0)
                            continue;

                        // Step 1. Calculate average of neighbours

                        int neighbours = 0;
                        double altitudeTotal = 0.0;
                        double altitudeMe = map[x, y] + water[x, y];

                        int NEIGHBOUR_ME = 4;

                        int NEIGHBOUR_MAX = type == NeighbourSystem.Moore ? 9 : 5;

                        for (int j = 0; j < NEIGHBOUR_MAX; j++)
                        {
                            if (j != NEIGHBOUR_ME)
                            {
                                int[] coords = Neighbours(type, j);

                                coords[0] += x;
                                coords[1] += y;

                                if (coords[0] > map.Width - 1)
                                    continue;
                                if (coords[1] > map.Height - 1)
                                    continue;
                                if (coords[0] < 0)
                                    continue;
                                if (coords[1] < 0)
                                    continue;

                                // Calculate total height of this neighbour
                                double altitudeNeighbour = water[coords[0], coords[1]] + map[coords[0], coords[1]];

                                // If it's greater than me...
                                if (altitudeNeighbour - altitudeMe < 0)
                                {
                                    // Add it to our calculations
                                    neighbours++;
                                    altitudeTotal += altitudeNeighbour;
                                }
                            }
                        }

                        if (neighbours == 0)
                            continue;

                        double altitudeAvg = altitudeTotal / neighbours;

                        // Step 2. Allocate water to neighbours.
                        for (int j = 0; j < NEIGHBOUR_MAX; j++)
                        {
                            if (j != NEIGHBOUR_ME)
                            {
                                int[] coords = Neighbours(type, j);

                                coords[0] += x;
                                coords[1] += y;

                                if (coords[0] > map.Width - 1)
                                    continue;
                                if (coords[1] > map.Height - 1)
                                    continue;
                                if (coords[0] < 0)
                                    continue;
                                if (coords[1] < 0)
                                    continue;

                                // Skip if we dont have water to begin with.
                                if (water[x, y] < 0)
                                    continue;

                                // Calculate our delta average
                                double altitudeDelta = altitudeMe - altitudeAvg;

                                if (altitudeDelta < 0)
                                    continue;

                                // Calculate how much water we can move
                                double waterMin = Math.Min(water[x, y], altitudeDelta);
                                double waterDelta = waterMin * ((water[coords[0], coords[1]] + map[coords[0], coords[1]])
                                                                / altitudeTotal);

                                double sedimentDelta = sediment[x, y] * (waterDelta / water[x, y]);

                                if (sedimentDelta > 0)
                                {
                                    sediment[x, y] -= sedimentDelta;
                                    sediment[coords[0], coords[1]] += sedimentDelta;
                                }
                            }
                        }
                    }
                }

                // Evaporate

                for (x = 0; x < water.Width; x++)
                {
                    for (y = 0; y < water.Height; y++)
                    {
                        water[x, y] *= 1.0 - (rainHeight / rounds);

                        double waterCapacity = waterSaturation * water[x, y];

                        double sedimentDeposit = sediment[x, y] - waterCapacity;
                        if (sedimentDeposit > 0)
                        {
                            sediment[x, y] -= sedimentDeposit;
                            map[x, y] += sedimentDeposit;
                        }
                    }
                }
            }

            // Deposit any remainder (should be minimal)
            for (x = 0; x < water.Width; x++)
                for (y = 0; y < water.Height; y++)
                    if (sediment[x, y] > 0)
                        map[x, y] += sediment[x, y];
        }

        #endregion
    }
}