gov/nasa/worldwind/PickSupport.java

   1 /*
   2 Copyright (C) 2001, 2006 United States Government
   3 as represented by the Administrator of the
   4 National Aeronautics and Space Administration.
   5 All Rights Reserved.
   6 */
   7 package gov.nasa.worldwind;
   8
   9 import gov.nasa.worldwind.geom.*;
  10
  11 import com.sun.opengl.util.*;
  12
  13 import javax.media.opengl.*;
  14 import java.util.*;
  15
  16 /**
  17  * @author tag
  18  * @version $Id: PickSupport.java 1754 2007-05-06 23:19:22Z tgaskins $
  19  */
  20 public class PickSupport
  21 {
  22     private HashMap<Integer, PickedObject> pickableObjects = new HashMap<Integer, PickedObject>();
  23
  24     public void clearPickList()
  25     {
  26         this.pickableObjects.clear();
  27     }
  28
  29     public void addPickableObject(int colorCode, Object o, Position position, boolean isTerrain)
  30     {
  31         this.pickableObjects.put(colorCode, new PickedObject(colorCode, o, position, isTerrain));
  32     }
  33
  34     public void addPickableObject(int colorCode, Object o)
  35     {
  36         this.pickableObjects.put(colorCode, new PickedObject(colorCode, o));
  37     }
  38
  39     public void addPickableObject(int colorCode, PickedObject po)
  40     {
  41         this.pickableObjects.put(colorCode, po);
  42     }
  43
  44     public PickedObject getTopObject(DrawContext dc, java.awt.Point pickPoint, Layer layer)
  45     {
  46         if (this.pickableObjects.isEmpty())
  47             return null;
  48
  49         int colorCode = this.getTopColor(dc, pickPoint);
  50         if (colorCode == dc.getClearColor().getRGB())
  51             return null;
  52
  53         PickedObject pickedObject = pickableObjects.get(colorCode);
  54         if (pickedObject == null)
  55             return null;
  56
  57         if (layer != null)
  58             pickedObject.setParentLayer(layer);
  59
  60         return pickedObject;
  61     }
  62
  63     public void resolvePick(DrawContext dc, java.awt.Point pickPoint, Layer layer)
  64     {
  65         PickedObject pickedObject = this.getTopObject(dc, pickPoint, layer);
  66         if (pickedObject != null)
  67             dc.addPickedObject(pickedObject);
  68
  69         this.clearPickList();
  70     }
  71
  72     public int getTopColor(DrawContext dc, java.awt.Point pickPoint)
  73     {
  74         GL gl = dc.getGL();
  75
  76         int[] viewport = new int[4];
  77         gl.glGetIntegerv(GL.GL_VIEWPORT, viewport, 0);
  78
  79         java.nio.ByteBuffer pixel = BufferUtil.newByteBuffer(3);
  80         gl.glReadPixels(pickPoint.x, viewport[3] - pickPoint.y, 1, 1,
  81             javax.media.opengl.GL.GL_RGB, GL.GL_UNSIGNED_BYTE, pixel);
  82
  83         java.awt.Color topColor = null;
  84         try
  85         {
  86             topColor = new java.awt.Color(pixel.get(0) & 0xff, pixel.get(1) & 0xff, pixel.get(2) & 0xff, 0);
  87         }
  88         catch (Exception e)
  89         {
  90             String message = WorldWind.retrieveErrMsg("layers.InvalidPickColorRead");
  91             WorldWind.logger().log(java.util.logging.Level.FINE, message);
  92         }
  93
  94         return topColor != null ? topColor.getRGB() : 0;
  95     }
  96
  97     public void beginPicking(DrawContext dc)
  98     {
  99         javax.media.opengl.GL gl = dc.getGL();
 100
 101         gl.glPushAttrib(GL.GL_ENABLE_BIT);
 102
 103         gl.glDisable(GL.GL_DITHER);
 104         gl.glDisable(GL.GL_LIGHTING);
 105         gl.glDisable(GL.GL_FOG);
 106         gl.glDisable(GL.GL_BLEND);
 107         gl.glDisable(GL.GL_TEXTURE_2D);
 108     }
 109
 110     public void endPicking(DrawContext dc)
 111     {
 112         dc.getGL().glPopAttrib();
 113     }
 114 }