src/edu/mit/ezyang/gravity/j3d/SmartPickTranslateBehavior.java

   1 package edu.mit.ezyang.gravity.j3d;
   2
   3 import com.sun.j3d.utils.picking.behaviors.*;
   4 import com.sun.j3d.utils.picking.*;
   5 import com.sun.j3d.utils.behaviors.mouse.*;
   6 import javax.media.j3d.*;
   7
   8 /**
   9  * Reimplemented PickTranslateBehavior, but uses SmartMouseTranslate, which
  10  * has been customized to take into account rotations relative to the surface
  11  * display. Modifications are solely in constructor and new setRotateTransformGroup
  12  * method.
  13  * @warning Convenience constructor with pick mode parameter not implemented.
  14  * @author Edward Z. Yang <ezyang@mit.edu>
  15  */
  16 public class SmartPickTranslateBehavior extends PickMouseBehavior implements MouseBehaviorCallback {
  17
  18     private SmartMouseTranslate translate;
  19     private PickingCallback callback = null;
  20     private TransformGroup currentTG;
  21
  22     /**
  23      * Propagates rotation transform group to SmartMouseTranslate in order
  24      * to provide appropriate information to transform.
  25      * @note We only support one rotation transform group; this should be
  26      *       enough for people with shallow object graphs.
  27      * @param group TransformGroup with rotation we need to adjust to
  28      */
  29     public void setRotateTransformGroup(TransformGroup group) {
  30         translate.setRotateTransformGroup(group);
  31     }
  32
  33     /**
  34      * Creates a pick/translate behavior that waits for user mouse events for
  35      * the scene graph.
  36      * @param root   Root of your scene graph.
  37      * @param canvas Java 3D drawing canvas.
  38      * @param bounds Bounds of your scene.
  39      **/
  40     public SmartPickTranslateBehavior(BranchGroup root, Canvas3D canvas, Bounds bounds) {
  41         super(canvas, root, bounds);
  42         translate = new SmartMouseTranslate(MouseBehavior.MANUAL_WAKEUP);
  43         translate.setTransformGroup(currGrp);
  44         currGrp.addChild(translate);
  45         translate.setSchedulingBounds(bounds);
  46         this.setSchedulingBounds(bounds);
  47     }
  48
  49     // below code is copied verbatim from com.sun.j3d.utils.picking.behaviors
  50
  51     /**
  52      * Update the scene to manipulate any nodes. This is not meant to be
  53      * called by users. Behavior automatically calls this. You can call
  54      * this only if you know what you are doing.
  55      *
  56      * @param xpos Current mouse X pos.
  57      * @param ypos Current mouse Y pos.
  58      **/
  59     public void updateScene(int xpos, int ypos) {
  60         TransformGroup tg = null;
  61
  62         if (!mevent.isAltDown() && mevent.isMetaDown()) {
  63
  64             pickCanvas.setShapeLocation(xpos, ypos);
  65             PickResult pr = pickCanvas.pickClosest();
  66             if ((pr != null) &&
  67                     ((tg = (TransformGroup) pr.getNode(PickResult.TRANSFORM_GROUP)) != null) &&
  68                     (tg.getCapability(TransformGroup.ALLOW_TRANSFORM_READ)) &&
  69                     (tg.getCapability(TransformGroup.ALLOW_TRANSFORM_WRITE))) {
  70
  71                 translate.setTransformGroup(tg);
  72                 translate.wakeup();
  73                 currentTG = tg;
  74             // Need to clean up Issue 123 --- Chien
  75             // freePickResult(pr);
  76             } else if (callback != null) {
  77                 callback.transformChanged(PickingCallback.NO_PICK, null);
  78             }
  79         }
  80
  81     }
  82
  83     /**
  84      * Callback method from MouseTranslate
  85      * This is used when the Picking callback is enabled
  86      */
  87     public void transformChanged(int type, Transform3D transform) {
  88         callback.transformChanged(PickingCallback.TRANSLATE, currentTG);
  89     }
  90
  91     /**
  92      * Register the class @param callback to be called each
  93      * time the picked object moves
  94      */
  95     public void setupCallback(PickingCallback callback) {
  96         this.callback = callback;
  97         if (callback == null) {
  98             translate.setupCallback(null);
  99         } else {
 100             translate.setupCallback(this);
 101         }
 102     }
 103 }