1/*
2 * Copyright (c) 2009-2010 jMonkeyEngine
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 * * Redistributions of source code must retain the above copyright
10 *   notice, this list of conditions and the following disclaimer.
11 *
12 * * Redistributions in binary form must reproduce the above copyright
13 *   notice, this list of conditions and the following disclaimer in the
14 *   documentation and/or other materials provided with the distribution.
15 *
16 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
17 *   may be used to endorse or promote products derived from this software
18 *   without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
24 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32package com.jme3.terrain.geomipmap.lodcalc;
33
34import com.jme3.export.InputCapsule;
35import com.jme3.export.JmeExporter;
36import com.jme3.export.JmeImporter;
37import com.jme3.export.OutputCapsule;
38import com.jme3.math.Vector3f;
39import com.jme3.terrain.geomipmap.TerrainPatch;
40import com.jme3.terrain.geomipmap.UpdatedTerrainPatch;
41import java.io.IOException;
42import java.util.HashMap;
43import java.util.List;
44
45/**
46 * Calculates the LOD of the terrain based on its distance from the
47 * cameras. Taking the minimum distance from all cameras.
48 *
49 * @author bowens
50 */
51public class DistanceLodCalculator implements LodCalculator {
52
53    private int size; // size of a terrain patch
54    private float lodMultiplier = 2;
55    private boolean turnOffLod = false;
56
57    public DistanceLodCalculator() {
58    }
59
60    public DistanceLodCalculator(int patchSize, float multiplier) {
61        this.size = patchSize;
62        this.lodMultiplier = multiplier;
63    }
64
65    public boolean calculateLod(TerrainPatch terrainPatch, List<Vector3f> locations, HashMap<String, UpdatedTerrainPatch> updates) {
66        float distance = getCenterLocation(terrainPatch).distance(locations.get(0));
67
68
69        if (turnOffLod) {
70            // set to full detail
71            int prevLOD = terrainPatch.getLod();
72            UpdatedTerrainPatch utp = updates.get(terrainPatch.getName());
73            if (utp == null) {
74                utp = new UpdatedTerrainPatch(terrainPatch, 0);
75                updates.put(utp.getName(), utp);
76            }
77            utp.setNewLod(0);
78            utp.setPreviousLod(prevLOD);
79            utp.setReIndexNeeded(true);
80            return true;
81        }
82
83        // go through each lod level to find the one we are in
84        for (int i = 0; i <= terrainPatch.getMaxLod(); i++) {
85            if (distance < getLodDistanceThreshold() * (i + 1)*terrainPatch.getWorldScale().x || i == terrainPatch.getMaxLod()) {
86                boolean reIndexNeeded = false;
87                if (i != terrainPatch.getLod()) {
88                    reIndexNeeded = true;
89                    //System.out.println("lod change: "+lod+" > "+i+"    dist: "+distance);
90                }
91                int prevLOD = terrainPatch.getLod();
92                //previousLod = lod;
93                //lod = i;
94                UpdatedTerrainPatch utp = updates.get(terrainPatch.getName());
95                if (utp == null) {
96                    utp = new UpdatedTerrainPatch(terrainPatch, i);//save in here, do not update actual variables
97                    updates.put(utp.getName(), utp);
98                }
99                utp.setPreviousLod(prevLOD);
100                utp.setReIndexNeeded(reIndexNeeded);
101
102                return reIndexNeeded;
103            }
104        }
105
106        return false;
107    }
108
109    protected Vector3f getCenterLocation(TerrainPatch terrainPatch) {
110        Vector3f loc = terrainPatch.getWorldTranslation().clone();
111        loc.x += terrainPatch.getSize()*terrainPatch.getWorldScale().x / 2;
112        loc.z += terrainPatch.getSize()*terrainPatch.getWorldScale().z / 2;
113        return loc;
114    }
115
116    public void write(JmeExporter ex) throws IOException {
117        OutputCapsule oc = ex.getCapsule(this);
118        oc.write(size, "patchSize", 32);
119        oc.write(lodMultiplier, "lodMultiplier", 32);
120    }
121
122    public void read(JmeImporter im) throws IOException {
123        InputCapsule ic = im.getCapsule(this);
124        size = ic.readInt("patchSize", 32);
125        lodMultiplier = ic.readFloat("lodMultiplier", 2.7f);
126    }
127
128    @Override
129    public LodCalculator clone() {
130        DistanceLodCalculator clone = new DistanceLodCalculator(size, lodMultiplier);
131        return clone;
132    }
133
134    @Override
135    public String toString() {
136        return "DistanceLodCalculator "+size+"*"+lodMultiplier;
137    }
138
139    /**
140     * Gets the camera distance where the LOD level will change
141     */
142    protected float getLodDistanceThreshold() {
143        return size*lodMultiplier;
144    }
145
146    /**
147     * Does this calculator require the terrain to have the difference of
148     * LOD levels of neighbours to be more than 1.
149     */
150    public boolean usesVariableLod() {
151        return false;
152    }
153
154    public float getLodMultiplier() {
155        return lodMultiplier;
156    }
157
158    public void setLodMultiplier(float lodMultiplier) {
159        this.lodMultiplier = lodMultiplier;
160    }
161
162    public int getSize() {
163        return size;
164    }
165
166    public void setSize(int size) {
167        this.size = size;
168    }
169
170    public void turnOffLod() {
171        turnOffLod = true;
172    }
173
174    public boolean isLodOff() {
175        return turnOffLod;
176    }
177
178    public void turnOnLod() {
179        turnOffLod = false;
180    }
181
182}
183