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      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  */
     32 package com.jme3.terrain.geomipmap.lodcalc;
     33 
     34 import com.jme3.export.InputCapsule;
     35 import com.jme3.export.JmeExporter;
     36 import com.jme3.export.JmeImporter;
     37 import com.jme3.export.OutputCapsule;
     38 import com.jme3.math.Vector3f;
     39 import com.jme3.terrain.geomipmap.TerrainPatch;
     40 import com.jme3.terrain.geomipmap.UpdatedTerrainPatch;
     41 import java.io.IOException;
     42 import java.util.HashMap;
     43 import 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  */
     51 public 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