Java/3D/Collision

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Intersect Test

   <source lang="java">

/*

* @(#)IntersectTest.java 1.10 02/10/21 13:48:59
* 
* Copyright (c) 1996-2002 Sun Microsystems, Inc. All Rights Reserved.
* 
* 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. - Redistribution 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 Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
* 
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGES.
* 
* You acknowledge that Software is not designed,licensed or intended for use in
* the design, construction, operation or maintenance of any nuclear facility.
*/

import java.applet.Applet; import java.awt.AWTEvent; import java.awt.BorderLayout; import java.awt.GraphicsConfiguration; import java.awt.event.MouseEvent; import java.util.Enumeration; import javax.media.j3d.AmbientLight; import javax.media.j3d.Appearance; import javax.media.j3d.Behavior; import javax.media.j3d.BoundingSphere; import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.DirectionalLight; import javax.media.j3d.GeometryArray; import javax.media.j3d.Group; import javax.media.j3d.LineArray; import javax.media.j3d.Material; import javax.media.j3d.Node; import javax.media.j3d.PointArray; import javax.media.j3d.PolygonAttributes; import javax.media.j3d.QuadArray; import javax.media.j3d.Shape3D; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.TriangleArray; import javax.media.j3d.View; import javax.media.j3d.WakeupCriterion; import javax.media.j3d.WakeupOnAWTEvent; import javax.vecmath.Color3f; import javax.vecmath.Color4f; import javax.vecmath.Point3d; import javax.vecmath.Point3f; import javax.vecmath.Vector3d; import javax.vecmath.Vector3f; import com.sun.j3d.utils.applet.MainFrame; import com.sun.j3d.utils.behaviors.keyboard.KeyNavigatorBehavior; import com.sun.j3d.utils.geometry.Sphere; import com.sun.j3d.utils.picking.PickCanvas; import com.sun.j3d.utils.picking.PickIntersection; import com.sun.j3d.utils.picking.PickResult; import com.sun.j3d.utils.picking.PickTool; import com.sun.j3d.utils.universe.SimpleUniverse; public class IntersectTest extends Applet {

 BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0),
     1000.0);
 private SimpleUniverse u = null;
 public BranchGroup createSceneGraph() {
   // Create the root of the branch graph
   BranchGroup objRoot = new BranchGroup();
   // Set up the ambient light
   Color3f ambientColor = new Color3f(0.1f, 0.1f, 0.1f);
   AmbientLight ambientLightNode = new AmbientLight(ambientColor);
   ambientLightNode.setInfluencingBounds(bounds);
   objRoot.addChild(ambientLightNode);
   // Set up the directional lights
   Color3f light1Color = new Color3f(1.0f, 1.0f, 0.9f);
   Vector3f light1Direction = new Vector3f(4.0f, -7.0f, -12.0f);
   Color3f light2Color = new Color3f(0.3f, 0.3f, 0.4f);
   Vector3f light2Direction = new Vector3f(-6.0f, -2.0f, -1.0f);
   DirectionalLight light1 = new DirectionalLight(light1Color,
       light1Direction);
   light1.setInfluencingBounds(bounds);
   objRoot.addChild(light1);
   DirectionalLight light2 = new DirectionalLight(light2Color,
       light2Direction);
   light2.setInfluencingBounds(bounds);
   objRoot.addChild(light2);
   Transform3D t3 = new Transform3D();
   // Shapes
   for (int x = 0; x < 3; x++) {
     for (int y = 0; y < 3; y++) {
       for (int z = 0; z < 3; z++) {
         t3.setTranslation(new Vector3d(-4 + x * 4.0, -4 + y * 4.0,
             -20 - z * 4.0));
         TransformGroup objTrans = new TransformGroup(t3);
         objRoot.addChild(objTrans);
         // Create a simple shape leaf node, add it to the scene
         // graph.
         GeometryArray geom = null;
         if (((x + y + z) % 2) == 0) {
           geom = new RandomColorCube();
         } else {
           geom = new RandomColorTetrahedron();
         }
         Shape3D shape = new Shape3D(geom);
         // use the utility method to set the capabilities
         PickTool.setCapabilities(shape, PickTool.INTERSECT_FULL);
         objTrans.addChild(shape);
       }
     }
   }
   // Lines
   Point3f[] verts = { new Point3f(-2.0f, 0.0f, 0.0f),
       new Point3f(2.0f, 0.0f, 0.0f) };
   Color3f grey = new Color3f(0.7f, 0.7f, 0.7f);
   Color3f[] colors = { grey, grey };
   for (int y = 0; y < 5; y++) {
     for (int z = 0; z < 5; z++) {
       t3.setTranslation(new Vector3d(7.0, -4 + y * 2.0, -20.0 - z
           * 2.0));
       TransformGroup objTrans = new TransformGroup(t3);
       objRoot.addChild(objTrans);
       LineArray la = new LineArray(verts.length,
           LineArray.COORDINATES | LineArray.COLOR_3);
       la.setCoordinates(0, verts);
       la.setColors(0, colors);
       Shape3D shape = new Shape3D();
       shape.setGeometry(la);
       // use the utility method to set the capabilities
       PickTool.setCapabilities(shape, PickTool.INTERSECT_FULL);
       objTrans.addChild(shape);
     }
   }
   // Points
   for (double x = -2.0; x <= 2.0; x += 1.0) {
     for (double y = -2.0; y <= 2.0; y += 1.0) {
       for (double z = -2.0; z <= 2.0; z += 1.0) {
         t3.setTranslation(new Vector3d(-10.0 + 2.0 * x,
             0.0 + 2.0 * y, -20.0 + 2.0 * z));
         TransformGroup objTrans = new TransformGroup(t3);
         objRoot.addChild(objTrans);
         PointArray pa = new PointArray(1, PointArray.COORDINATES
             | PointArray.COLOR_3);
         pa.setCoordinate(0, new Point3d(0.0, 0.0, 0.0));
         pa.setColor(0, grey);
         Shape3D shape = new Shape3D();
         shape.setGeometry(pa);
         // use the utility method to set the capabilities
         PickTool.setCapabilities(shape, PickTool.INTERSECT_FULL);
         objTrans.addChild(shape);
       }
     }
   }
   return objRoot;
 }
 public IntersectTest() {
 }
 public void init() {
   setLayout(new BorderLayout());
   GraphicsConfiguration config = SimpleUniverse
       .getPreferredConfiguration();
   Canvas3D c = new Canvas3D(config);
   add("Center", c);
   // Create a simple scene and attach it to the virtual universe
   BranchGroup scene = createSceneGraph();
   u = new SimpleUniverse(c);
   // Add picking behavior
   IntersectInfoBehavior behavior = new IntersectInfoBehavior(c, scene,
       0.05f);
   behavior.setSchedulingBounds(bounds);
   scene.addChild(behavior);
   TransformGroup vpTrans = u.getViewingPlatform()
       .getViewPlatformTransform();
   KeyNavigatorBehavior keybehavior = new KeyNavigatorBehavior(vpTrans);
   keybehavior.setSchedulingBounds(bounds);
   scene.addChild(keybehavior);
   scene.setCapability(Group.ALLOW_CHILDREN_EXTEND);
   scene.rupile();
   u.addBranchGraph(scene);
   View view = u.getViewer().getView();
   view.setBackClipDistance(100000);
 }
 public void destroy() {
   u.cleanup();
 }
 //
 // The following allows IntersectTest to be run as an application
 // as well as an applet
 //
 public static void main(String[] args) {
   String s = "\n\nIntersectTest:\n-----------\n";
   s += "Pick with the mouse over the primitives\n";
   s += "- A sphere will be placed to indicate the picked point.\n";
   s += "If color information is available, the sphere will change color to reflect\n";
   s += "the interpolated color.\n";
   s += "- Other spheres will be placed to show the vertices of the selected polygon\n";
   s += "- Information will be displayed about the picking operation\n\n\n";
   System.out.println(s);
   new MainFrame(new IntersectTest(), 640, 640);
 }

} class RandomColorTetrahedron extends TriangleArray {

 RandomColorTetrahedron() {
   super(12, GeometryArray.COORDINATES | GeometryArray.COLOR_3);
   Point3f verts[] = new Point3f[4];
   Color3f colors[] = new Color3f[4];
   verts[0] = new Point3f(0.5f, 0.5f, 0.5f);
   verts[1] = new Point3f(0.5f, -0.5f, -0.5f);
   verts[2] = new Point3f(-0.5f, -0.5f, 0.5f);
   verts[3] = new Point3f(-0.5f, 0.5f, -0.5f);
   colors[0] = new Color3f(1.0f, 0.0f, 0.0f);
   colors[1] = new Color3f(0.0f, 1.0f, 0.0f);
   colors[2] = new Color3f(0.0f, 0.0f, 1.0f);
   Point3f pnts[] = new Point3f[12];
   Color3f clrs[] = new Color3f[12];
   pnts[0] = verts[2];
   clrs[0] = colors[(int) (Math.random() * 3.0)];
   pnts[1] = verts[1];
   clrs[1] = colors[(int) (Math.random() * 3.0)];
   pnts[2] = verts[0];
   clrs[2] = colors[(int) (Math.random() * 3.0)];
   pnts[3] = verts[3];
   clrs[3] = colors[(int) (Math.random() * 3.0)];
   pnts[4] = verts[2];
   clrs[4] = colors[(int) (Math.random() * 3.0)];
   pnts[5] = verts[0];
   clrs[5] = colors[(int) (Math.random() * 3.0)];
   pnts[6] = verts[1];
   clrs[6] = colors[(int) (Math.random() * 3.0)];
   pnts[7] = verts[2];
   clrs[7] = colors[(int) (Math.random() * 3.0)];
   pnts[8] = verts[3];
   clrs[8] = colors[(int) (Math.random() * 3.0)];
   pnts[9] = verts[1];
   clrs[9] = colors[(int) (Math.random() * 3.0)];
   pnts[10] = verts[3];
   clrs[10] = colors[(int) (Math.random() * 3.0)];
   pnts[11] = verts[0];
   clrs[11] = colors[(int) (Math.random() * 3.0)];
   setCoordinates(0, pnts);
   setColors(0, clrs);
 }

} class RandomColorCube extends QuadArray {

 RandomColorCube() {
   super(24, GeometryArray.COORDINATES | GeometryArray.COLOR_3);
   Point3f verts[] = new Point3f[8];
   Color3f colors[] = new Color3f[3];
   verts[0] = new Point3f(0.5f, 0.5f, 0.5f);
   verts[1] = new Point3f(-0.5f, 0.5f, 0.5f);
   verts[2] = new Point3f(-0.5f, -0.5f, 0.5f);
   verts[3] = new Point3f(0.5f, -0.5f, 0.5f);
   verts[4] = new Point3f(0.5f, 0.5f, -0.5f);
   verts[5] = new Point3f(-0.5f, 0.5f, -0.5f);
   verts[6] = new Point3f(-0.5f, -0.5f, -0.5f);
   verts[7] = new Point3f(0.5f, -0.5f, -0.5f);
   colors[0] = new Color3f(1.0f, 0.0f, 0.0f);
   colors[1] = new Color3f(0.0f, 1.0f, 0.0f);
   colors[2] = new Color3f(0.0f, 0.0f, 1.0f);
   Point3f pnts[] = new Point3f[24];
   Color3f clrs[] = new Color3f[24];
   pnts[0] = verts[0];
   clrs[0] = colors[(int) (Math.random() * 3.0)];
   pnts[1] = verts[3];
   clrs[1] = colors[(int) (Math.random() * 3.0)];
   pnts[2] = verts[7];
   clrs[2] = colors[(int) (Math.random() * 3.0)];
   pnts[3] = verts[4];
   clrs[3] = colors[(int) (Math.random() * 3.0)];
   pnts[4] = verts[1];
   clrs[4] = colors[(int) (Math.random() * 3.0)];
   pnts[5] = verts[5];
   clrs[5] = colors[(int) (Math.random() * 3.0)];
   pnts[6] = verts[6];
   clrs[6] = colors[(int) (Math.random() * 3.0)];
   pnts[7] = verts[2];
   clrs[7] = colors[(int) (Math.random() * 3.0)];
   pnts[8] = verts[0];
   clrs[8] = colors[(int) (Math.random() * 3.0)];
   pnts[9] = verts[4];
   clrs[9] = colors[(int) (Math.random() * 3.0)];
   pnts[10] = verts[5];
   clrs[10] = colors[(int) (Math.random() * 3.0)];
   pnts[11] = verts[1];
   clrs[11] = colors[(int) (Math.random() * 3.0)];
   pnts[12] = verts[3];
   clrs[12] = colors[(int) (Math.random() * 3.0)];
   pnts[13] = verts[2];
   clrs[13] = colors[(int) (Math.random() * 3.0)];
   pnts[14] = verts[6];
   clrs[14] = colors[(int) (Math.random() * 3.0)];
   pnts[15] = verts[7];
   clrs[15] = colors[(int) (Math.random() * 3.0)];
   pnts[16] = verts[0];
   clrs[16] = colors[(int) (Math.random() * 3.0)];
   pnts[17] = verts[1];
   clrs[17] = colors[(int) (Math.random() * 3.0)];
   pnts[18] = verts[2];
   clrs[18] = colors[(int) (Math.random() * 3.0)];
   pnts[19] = verts[3];
   clrs[19] = colors[(int) (Math.random() * 3.0)];
   pnts[20] = verts[7];
   clrs[20] = colors[(int) (Math.random() * 3.0)];
   pnts[21] = verts[6];
   clrs[21] = colors[(int) (Math.random() * 3.0)];
   pnts[22] = verts[5];
   clrs[22] = colors[(int) (Math.random() * 3.0)];
   pnts[23] = verts[4];
   clrs[23] = colors[(int) (Math.random() * 3.0)];
   setCoordinates(0, pnts);
   setColors(0, clrs);
 }

} /**

* Class: IntersectInfoBehavior
* 
* Description: Used to respond to mouse pick and drag events in the 3D window.
* Displays information about the pick.
* 
* Version: 1.0
*  
*/

class IntersectInfoBehavior extends Behavior {

 float size;
 PickCanvas pickCanvas;
 PickResult[] pickResult;
 Appearance oldlook, redlookwf, redlook, greenlook, bluelook;
 Node oldNode = null;
 GeometryArray oldGeom = null;
 Color3f redColor = new Color3f(1.0f, 0.0f, 0.0f);
 TransformGroup[] sphTrans = new TransformGroup[6];
 Sphere[] sph = new Sphere[6];
 Transform3D spht3 = new Transform3D();
 public IntersectInfoBehavior(Canvas3D canvas3D, BranchGroup branchGroup,
     float size) {
   pickCanvas = new PickCanvas(canvas3D, branchGroup);
   pickCanvas.setTolerance(5.0f);
   pickCanvas.setMode(PickCanvas.GEOMETRY_INTERSECT_INFO);
   this.size = size;
   // Create an Appearance.
   redlook = new Appearance();
   Color3f objColor = new Color3f(0.5f, 0.0f, 0.0f);
   Color3f black = new Color3f(0.0f, 0.0f, 0.0f);
   Color3f white = new Color3f(1.0f, 1.0f, 1.0f);
   redlook.setMaterial(new Material(objColor, black, objColor, white,
       50.0f));
   redlook.setCapability(Appearance.ALLOW_MATERIAL_WRITE);
   redlookwf = new Appearance();
   redlookwf.setMaterial(new Material(objColor, black, objColor, white,
       50.0f));
   PolygonAttributes pa = new PolygonAttributes();
   pa.setPolygonMode(pa.POLYGON_LINE);
   pa.setCullFace(pa.CULL_NONE);
   redlookwf.setPolygonAttributes(pa);
   oldlook = new Appearance();
   objColor = new Color3f(1.0f, 1.0f, 1.0f);
   oldlook.setMaterial(new Material(objColor, black, objColor, white,
       50.0f));
   greenlook = new Appearance();
   objColor = new Color3f(0.0f, 0.8f, 0.0f);
   greenlook.setMaterial(new Material(objColor, black, objColor, white,
       50.0f));
   bluelook = new Appearance();
   objColor = new Color3f(0.0f, 0.0f, 0.8f);
   bluelook.setMaterial(new Material(objColor, black, objColor, white,
       50.0f));
   for (int i = 0; i < 6; i++) {
     switch (i) {
     case 0:
       sph[i] = new Sphere(size * 1.15f, redlook);
       break;
     case 1:
       sph[i] = new Sphere(size * 1.1f, greenlook);
       break;
     default:
       sph[i] = new Sphere(size, bluelook);
       break;
     }
     sph[i].setPickable(false);
     sphTrans[i] = new TransformGroup();
     sphTrans[i].setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
     sphTrans[i].setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
     // Add sphere, transform
     branchGroup.addChild(sphTrans[i]);
     sphTrans[i].addChild(sph[i]);
   }
 }
 public void initialize() {
   wakeupOn(new WakeupOnAWTEvent(MouseEvent.MOUSE_PRESSED));
 }
 public void processStimulus(Enumeration criteria) {
   WakeupCriterion wakeup;
   AWTEvent[] event;
   int eventId;
   while (criteria.hasMoreElements()) {
     wakeup = (WakeupCriterion) criteria.nextElement();
     if (wakeup instanceof WakeupOnAWTEvent) {
       event = ((WakeupOnAWTEvent) wakeup).getAWTEvent();
       for (int i = 0; i < event.length; i++) {
         eventId = event[i].getID();
         if (eventId == MouseEvent.MOUSE_PRESSED) {
           int x = ((MouseEvent) event[i]).getX();
           int y = ((MouseEvent) event[i]).getY();
           pickCanvas.setShapeLocation(x, y);
           Point3d eyePos = pickCanvas.getStartPosition();
           pickResult = pickCanvas.pickAllSorted();
           // Use this to do picking benchmarks
           /*
            * long start = System.currentTimeMillis(); for (int
            * l=0;l <3;l++) { if (l == 0) System.out.print
            * ("BOUNDS: "); if (l == 1) System.out.print
            * ("GEOMETRY: "); if (l == 2) System.out.print
            * ("GEOMETRY_INTERSECT_INFO: ");
            * 
            * for (int k=0;k <1000;k++) { if (l == 0) {
            * pickCanvas.setMode(PickTool.BOUNDS); pickResult =
            * pickCanvas.pickAllSorted(); } if (l == 1) {
            * pickCanvas.setMode(PickTool.GEOMETRY); pickResult =
            * pickCanvas.pickAllSorted(); } if (l == 2) {
            * pickCanvas.setMode(PickTool.GEOMETRY_INTERSECT_INFO);
            * pickResult = pickCanvas.pickAllSorted(); } } long
            * delta = System.currentTimeMillis() - start;
            * System.out.println ("\t"+delta+" ms / 1000 picks"); }
            */
           if (pickResult != null) {
             // Get closest intersection results
             PickIntersection pi = pickResult[0]
                 .getClosestIntersection(eyePos);
             GeometryArray curGeomArray = pi.getGeometryArray();
             // Position sphere at intersection point
             Vector3d v = new Vector3d();
             Point3d intPt = pi.getPointCoordinatesVW();
             v.set(intPt);
             spht3.setTranslation(v);
             sphTrans[0].setTransform(spht3);
             // Position sphere at closest vertex
             Point3d closestVert = pi
                 .getClosestVertexCoordinatesVW();
             v.set(closestVert);
             spht3.setTranslation(v);
             sphTrans[1].setTransform(spht3);
             Point3d[] ptw = pi.getPrimitiveCoordinatesVW();
             Point3d[] pt = pi.getPrimitiveCoordinates();
             int[] coordidx = pi.getPrimitiveCoordinateIndices();
             Point3d ptcoord = new Point3d();
             for (int k = 0; k < pt.length; k++) {
               v.set(ptw[k]);
               spht3.setTranslation(v);
               sphTrans[k + 2].setTransform(spht3);
             }
             // Get interpolated color (if available)
             Color4f iColor4 = null;
             Color3f iColor = null;
             Vector3f iNormal = null;
             if (curGeomArray != null) {
               int vf = curGeomArray.getVertexFormat();
               if (((vf & (GeometryArray.COLOR_3 | GeometryArray.COLOR_4)) != 0)
                   && (null != (iColor4 = pi
                       .getPointColor()))) {
                 iColor = new Color3f(iColor4.x, iColor4.y,
                     iColor4.z);
                 // Change the point"s color
                 redlook.setMaterial(new Material(iColor,
                     new Color3f(0.0f, 0.0f, 0.0f),
                     iColor, new Color3f(1.0f, 1.0f,
                         1.0f), 50.0f));
               }
               if (((vf & GeometryArray.NORMALS) != 0)
                   && (null != (iNormal = pi
                       .getPointNormal()))) {
                 System.out.println("Interpolated normal: "
                     + iNormal);
               }
             }
             System.out.println("=============");
             System.out
                 .println("Coordinates of intersection pt:"
                     + intPt);
             System.out.println("Coordinates of vertices: ");
             for (int k = 0; k < pt.length; k++) {
               System.out.println(k + ":" + ptw[k].x + " "
                   + ptw[k].y + " " + ptw[k].z);
             }
             System.out
                 .println("Closest vertex: " + closestVert);
             if (iColor != null) {
               System.out.println("Interpolated color: "
                   + iColor);
             }
             if (iNormal != null) {
               System.out.println("Interpolated normal: "
                   + iNormal);
             }
           }
         }
       }
     }
   }
   wakeupOn(new WakeupOnAWTEvent(MouseEvent.MOUSE_PRESSED));
 }

}


      </source>
   
  
 
  



The use of the CollisionDetector

   <source lang="java">

import java.awt.BorderLayout; import java.awt.Button; import java.awt.Frame; import java.awt.Panel; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.Enumeration; import javax.media.j3d.AmbientLight; import javax.media.j3d.Appearance; import javax.media.j3d.Behavior; import javax.media.j3d.BoundingSphere; import javax.media.j3d.Bounds; import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.DirectionalLight; import javax.media.j3d.IndexedQuadArray; import javax.media.j3d.Locale; import javax.media.j3d.Material; import javax.media.j3d.Node; import javax.media.j3d.PhysicalBody; import javax.media.j3d.PhysicalEnvironment; import javax.media.j3d.Shape3D; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.View; import javax.media.j3d.ViewPlatform; import javax.media.j3d.VirtualUniverse; import javax.media.j3d.WakeupCriterion; import javax.media.j3d.WakeupOnCollisionEntry; import javax.media.j3d.WakeupOnCollisionExit; import javax.media.j3d.WakeupOnCollisionMovement; import javax.media.j3d.WakeupOr; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Point3f; import javax.vecmath.Vector3d; import javax.vecmath.Vector3f; import com.sun.j3d.utils.picking.behaviors.PickTranslateBehavior; /**

* This class demonstrates the use of the CollisionDetector class to perform
* processing when objects collide. When this program is run the white cube can
* be selected and moved by dragging on it with the right mouse button. You
* should notice that there is a problem if the movable cube comes into contact
* with both of the static cubes at one time. A way round this is given in the
* SimpleCollision2 application.
* 
* @see CollisionDetector
* @see SimpleCollision2
* @author I.J.Palmer
* @version 1.0
*/

public class SimpleCollision extends Frame implements ActionListener {

 protected Canvas3D myCanvas3D = new Canvas3D(null);
 protected Button exitButton = new Button("Exit");
 protected BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0,
     0.0), 100.0);
 /** Transform for the left cube. */
 protected TransformGroup leftGroup;
 /** Transform for the right cube */
 protected TransformGroup rightGroup;
 /**
  * Transform for the movable cube. This has read, write and pick reporting
  * capabilities enabled.
  */
 protected TransformGroup moveGroup;
 /** A transform to change the size of the movable cube. */
 protected TransformGroup scaleGroup;
 /** The left static cube. */
 protected Shape3D leftCube;
 /** The right static cube. */
 protected Shape3D rightCube;
 /** The movable cube that will collide with the other two cubes */
 protected Shape3D moveCube;
 /**
  * This builds the view branch of the scene graph.
  */
 protected BranchGroup buildViewBranch(Canvas3D c) {
   BranchGroup viewBranch = new BranchGroup();
   Transform3D viewXfm = new Transform3D();
   viewXfm.set(new Vector3f(0.0f, 0.0f, 10.0f));
   TransformGroup viewXfmGroup = new TransformGroup(viewXfm);
   ViewPlatform myViewPlatform = new ViewPlatform();
   PhysicalBody myBody = new PhysicalBody();
   PhysicalEnvironment myEnvironment = new PhysicalEnvironment();
   viewXfmGroup.addChild(myViewPlatform);
   viewBranch.addChild(viewXfmGroup);
   View myView = new View();
   myView.addCanvas3D(c);
   myView.attachViewPlatform(myViewPlatform);
   myView.setPhysicalBody(myBody);
   myView.setPhysicalEnvironment(myEnvironment);
   return viewBranch;
 }
 /**
  * This adds some lights to the content branch of the scene graph.
  * 
  * @param b
  *            The BranchGroup to add the lights to.
  */
 protected void addLights(BranchGroup b) {
   Color3f ambLightColour = new Color3f(0.5f, 0.5f, 0.5f);
   AmbientLight ambLight = new AmbientLight(ambLightColour);
   ambLight.setInfluencingBounds(bounds);
   Color3f dirLightColour = new Color3f(1.0f, 1.0f, 1.0f);
   Vector3f dirLightDir = new Vector3f(-1.0f, -1.0f, -1.0f);
   DirectionalLight dirLight = new DirectionalLight(dirLightColour,
       dirLightDir);
   dirLight.setInfluencingBounds(bounds);
   b.addChild(ambLight);
   b.addChild(dirLight);
 }
 /**
  * Creates the content branch of the scene graph.
  * 
  * @return BranchGroup with content attached.
  */
 protected BranchGroup buildContentBranch() {
   //First create a different appearance for each cube
   Appearance app1 = new Appearance();
   Appearance app2 = new Appearance();
   Appearance app3 = new Appearance();
   Color3f ambientColour1 = new Color3f(1.0f, 0.0f, 0.0f);
   Color3f ambientColour2 = new Color3f(1.0f, 1.0f, 0.0f);
   Color3f ambientColour3 = new Color3f(1.0f, 1.0f, 1.0f);
   Color3f emissiveColour = new Color3f(0.0f, 0.0f, 0.0f);
   Color3f specularColour = new Color3f(1.0f, 1.0f, 1.0f);
   Color3f diffuseColour1 = new Color3f(1.0f, 0.0f, 0.0f);
   Color3f diffuseColour2 = new Color3f(1.0f, 1.0f, 0.0f);
   Color3f diffuseColour3 = new Color3f(1.0f, 1.0f, 1.0f);
   float shininess = 20.0f;
   app1.setMaterial(new Material(ambientColour1, emissiveColour,
       diffuseColour1, specularColour, shininess));
   app2.setMaterial(new Material(ambientColour2, emissiveColour,
       diffuseColour2, specularColour, shininess));
   app3.setMaterial(new Material(ambientColour3, emissiveColour,
       diffuseColour3, specularColour, shininess));
   //Create the vertex data for the cube. Since each shape is
   //a cube we can use the same vertex data for each cube
   IndexedQuadArray indexedCube = new IndexedQuadArray(8,
       IndexedQuadArray.COORDINATES | IndexedQuadArray.NORMALS, 24);
   Point3f[] cubeCoordinates = { new Point3f(1.0f, 1.0f, 1.0f),
       new Point3f(-1.0f, 1.0f, 1.0f),
       new Point3f(-1.0f, -1.0f, 1.0f),
       new Point3f(1.0f, -1.0f, 1.0f), new Point3f(1.0f, 1.0f, -1.0f),
       new Point3f(-1.0f, 1.0f, -1.0f),
       new Point3f(-1.0f, -1.0f, -1.0f),
       new Point3f(1.0f, -1.0f, -1.0f) };
   Vector3f[] cubeNormals = { new Vector3f(0.0f, 0.0f, 1.0f),
       new Vector3f(0.0f, 0.0f, -1.0f),
       new Vector3f(1.0f, 0.0f, 0.0f),
       new Vector3f(-1.0f, 0.0f, 0.0f),
       new Vector3f(0.0f, 1.0f, 0.0f), new Vector3f(0.0f, -1.0f, 0.0f) };
   int cubeCoordIndices[] = { 0, 1, 2, 3, 7, 6, 5, 4, 0, 3, 7, 4, 5, 6, 2,
       1, 0, 4, 5, 1, 6, 7, 3, 2 };
   int cubeNormalIndices[] = { 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3,
       3, 3, 4, 4, 4, 4, 5, 5, 5, 5 };
   indexedCube.setCoordinates(0, cubeCoordinates);
   indexedCube.setNormals(0, cubeNormals);
   indexedCube.setCoordinateIndices(0, cubeCoordIndices);
   indexedCube.setNormalIndices(0, cubeNormalIndices);
   //Create the three cubes
   leftCube = new Shape3D(indexedCube, app1);
   rightCube = new Shape3D(indexedCube, app2);
   moveCube = new Shape3D(indexedCube, app3);
   //Define the user data so that we can print out the
   //name of the colliding cube.
   leftCube.setUserData(new String("left cube"));
   rightCube.setUserData(new String("right cube"));
   //Create the content branch and add the lights
   BranchGroup contentBranch = new BranchGroup();
   addLights(contentBranch);
   //Create and set up the movable cube"s TransformGroup.
   //This scales and translates the cube and then sets the
   // read, write and pick reporting capabilities.
   Transform3D moveXfm = new Transform3D();
   moveXfm.set(0.7, new Vector3d(0.0, 2.0, 1.0));
   moveGroup = new TransformGroup(moveXfm);
   moveGroup.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
   moveGroup.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
   moveGroup.setCapability(TransformGroup.ENABLE_PICK_REPORTING);
   //Create the left cube"s TransformGroup
   Transform3D leftGroupXfm = new Transform3D();
   leftGroupXfm.set(new Vector3d(-1.5, 0.0, 0.0));
   leftGroup = new TransformGroup(leftGroupXfm);
   //Create the right cube"s TransformGroup
   Transform3D rightGroupXfm = new Transform3D();
   rightGroupXfm.set(new Vector3d(1.5, 0.0, 0.0));
   rightGroup = new TransformGroup(rightGroupXfm);
   //Add the behaviour to allow us to move the cube
   PickTranslateBehavior pickTranslate = new PickTranslateBehavior(
       contentBranch, myCanvas3D, bounds);
   contentBranch.addChild(pickTranslate);
   //Add our CollisionDetector class to detect collisions with
   //the movable cube.
   CollisionDetector myColDet = new CollisionDetector(moveCube, bounds);
   contentBranch.addChild(myColDet);
   //Create the content branch hierarchy.
   contentBranch.addChild(moveGroup);
   contentBranch.addChild(leftGroup);
   contentBranch.addChild(rightGroup);
   moveGroup.addChild(moveCube);
   leftGroup.addChild(leftCube);
   rightGroup.addChild(rightCube);
   return contentBranch;
 }
 /**
  * Process the exit button action to exit the application.
  */
 public void actionPerformed(ActionEvent e) {
   if (e.getSource() == exitButton) {
     dispose();
     System.exit(0);
   }
 }
 public SimpleCollision() {
   VirtualUniverse myUniverse = new VirtualUniverse();
   Locale myLocale = new Locale(myUniverse);
   myLocale.addBranchGraph(buildViewBranch(myCanvas3D));
   myLocale.addBranchGraph(buildContentBranch());
   setTitle("SimpleWorld");
   setSize(400, 400);
   setLayout(new BorderLayout());
   Panel bottom = new Panel();
   bottom.add(exitButton);
   add(BorderLayout.CENTER, myCanvas3D);
   add(BorderLayout.SOUTH, bottom);
   exitButton.addActionListener(this);
   setVisible(true);
 }
 public static void main(String[] args) {
   SimpleCollision sw = new SimpleCollision();
 }

} /**

* A simple collision detector class. This responds to a collision event by
* printing a message with information about the type of collision event and the
* object that has been collided with.
* 
* @author I.J.Palmer
* @version 1.0
*/

class CollisionDetector extends Behavior {

 /** The separate criteria used to wake up this beahvior. */
 protected WakeupCriterion[] theCriteria;
 /** The OR of the separate criteria. */
 protected WakeupOr oredCriteria;
 /** The shape that is watched for collision. */
 protected Shape3D collidingShape;
 /**
  * @param theShape
  *            Shape3D that is to be watched for collisions.
  * @param theBounds
  *            Bounds that define the active region for this behaviour
  */
 public CollisionDetector(Shape3D theShape, Bounds theBounds) {
   collidingShape = theShape;
   setSchedulingBounds(theBounds);
 }
 /**
  * This creates an entry, exit and movement collision criteria. These are
  * then OR"ed together, and the wake up condition set to the result.
  */
 public void initialize() {
   theCriteria = new WakeupCriterion[3];
   theCriteria[0] = new WakeupOnCollisionEntry(collidingShape);
   theCriteria[1] = new WakeupOnCollisionExit(collidingShape);
   theCriteria[2] = new WakeupOnCollisionMovement(collidingShape);
   oredCriteria = new WakeupOr(theCriteria);
   wakeupOn(oredCriteria);
 }
 /**
  * Where the work is done in this class. A message is printed out using the
  * userData of the object collided with. The wake up condition is then set
  * to the OR"ed criterion again.
  */
 public void processStimulus(Enumeration criteria) {
   WakeupCriterion theCriterion = (WakeupCriterion) criteria.nextElement();
   if (theCriterion instanceof WakeupOnCollisionEntry) {
     Node theLeaf = ((WakeupOnCollisionEntry) theCriterion)
         .getTriggeringPath().getObject();
     System.out.println("Collided with " + theLeaf.getUserData());
   } else if (theCriterion instanceof WakeupOnCollisionExit) {
     Node theLeaf = ((WakeupOnCollisionExit) theCriterion)
         .getTriggeringPath().getObject();
     System.out.println("Stopped colliding with  "
         + theLeaf.getUserData());
   } else {
     Node theLeaf = ((WakeupOnCollisionMovement) theCriterion)
         .getTriggeringPath().getObject();
     System.out.println("Moved whilst colliding with "
         + theLeaf.getUserData());
   }
   wakeupOn(oredCriteria);
 }

}


      </source>
   
  
 
  



The use of two collision detectors to overcome the

   <source lang="java">

import java.awt.BorderLayout; import java.awt.Button; import java.awt.Frame; import java.awt.Panel; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.Enumeration; import javax.media.j3d.AmbientLight; import javax.media.j3d.Appearance; import javax.media.j3d.Behavior; import javax.media.j3d.BoundingSphere; import javax.media.j3d.Bounds; import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.DirectionalLight; import javax.media.j3d.IndexedQuadArray; import javax.media.j3d.Locale; import javax.media.j3d.Material; import javax.media.j3d.PhysicalBody; import javax.media.j3d.PhysicalEnvironment; import javax.media.j3d.Shape3D; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.View; import javax.media.j3d.ViewPlatform; import javax.media.j3d.VirtualUniverse; import javax.media.j3d.WakeupCriterion; import javax.media.j3d.WakeupOnCollisionEntry; import javax.media.j3d.WakeupOnCollisionExit; import javax.media.j3d.WakeupOnCollisionMovement; import javax.media.j3d.WakeupOr; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Point3f; import javax.vecmath.Vector3d; import javax.vecmath.Vector3f; import com.sun.j3d.utils.picking.behaviors.PickTranslateBehavior; /**

* This class demonstrates the use of two collision detectors to overcome the
* problem of an object colliding with more than one object at a time. The white
* cube is movable by dragging it with the right mouse button.
* 
* @see CollisionDetector2
* @author I.J.Palmer
* @version 1.0
*/

public class SimpleCollision2 extends Frame implements ActionListener {

 protected Canvas3D myCanvas3D = new Canvas3D(null);
 protected Button exitButton = new Button("Exit");
 protected BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0,
     0.0), 100.0);
 /** Transform for the left cube. */
 protected TransformGroup leftGroup;
 /** Transform for the right cube */
 protected TransformGroup rightGroup;
 /**
  * Transform for the movable cube. This has read, write and pick reporting
  * capabilities enabled.
  */
 protected TransformGroup moveGroup;
 /** The left static cube. */
 protected Shape3D leftCube;
 /** The right static cube. */
 protected Shape3D rightCube;
 /** The movable cube that will collide with the other two cubes */
 protected Shape3D moveCube;
 /**
  * This builds the view branch of the scene graph.
  * 
  * @return BranchGroup with viewing objects attached.
  */
 protected BranchGroup buildViewBranch(Canvas3D c) {
   BranchGroup viewBranch = new BranchGroup();
   Transform3D viewXfm = new Transform3D();
   viewXfm.set(new Vector3f(0.0f, 0.0f, 10.0f));
   TransformGroup viewXfmGroup = new TransformGroup(viewXfm);
   ViewPlatform myViewPlatform = new ViewPlatform();
   PhysicalBody myBody = new PhysicalBody();
   PhysicalEnvironment myEnvironment = new PhysicalEnvironment();
   viewXfmGroup.addChild(myViewPlatform);
   viewBranch.addChild(viewXfmGroup);
   View myView = new View();
   myView.addCanvas3D(c);
   myView.attachViewPlatform(myViewPlatform);
   myView.setPhysicalBody(myBody);
   myView.setPhysicalEnvironment(myEnvironment);
   return viewBranch;
 }
 /**
  * This adds some lights to the content branch of the scene graph.
  * 
  * @param b
  *            The BranchGroup to add the lights to.
  */
 protected void addLights(BranchGroup b) {
   Color3f ambLightColour = new Color3f(0.5f, 0.5f, 0.5f);
   AmbientLight ambLight = new AmbientLight(ambLightColour);
   ambLight.setInfluencingBounds(bounds);
   Color3f dirLightColour = new Color3f(1.0f, 1.0f, 1.0f);
   Vector3f dirLightDir = new Vector3f(-1.0f, -1.0f, -1.0f);
   DirectionalLight dirLight = new DirectionalLight(dirLightColour,
       dirLightDir);
   dirLight.setInfluencingBounds(bounds);
   b.addChild(ambLight);
   b.addChild(dirLight);
 }
 /**
  * Creates the content branch of the scene graph.
  * 
  * @return BranchGroup with content attached.
  */
 protected BranchGroup buildContentBranch() {
   //First create a different appearance for each cube
   Appearance app1 = new Appearance();
   Appearance app2 = new Appearance();
   Appearance app3 = new Appearance();
   Color3f ambientColour1 = new Color3f(1.0f, 0.0f, 0.0f);
   Color3f ambientColour2 = new Color3f(1.0f, 1.0f, 0.0f);
   Color3f ambientColour3 = new Color3f(1.0f, 1.0f, 1.0f);
   Color3f emissiveColour = new Color3f(0.0f, 0.0f, 0.0f);
   Color3f specularColour = new Color3f(1.0f, 1.0f, 1.0f);
   Color3f diffuseColour1 = new Color3f(1.0f, 0.0f, 0.0f);
   Color3f diffuseColour2 = new Color3f(1.0f, 1.0f, 0.0f);
   Color3f diffuseColour3 = new Color3f(1.0f, 1.0f, 1.0f);
   float shininess = 20.0f;
   app1.setMaterial(new Material(ambientColour1, emissiveColour,
       diffuseColour1, specularColour, shininess));
   app2.setMaterial(new Material(ambientColour2, emissiveColour,
       diffuseColour2, specularColour, shininess));
   app3.setMaterial(new Material(ambientColour3, emissiveColour,
       diffuseColour3, specularColour, shininess));
   //Build the vertex array for the cubes. We can use the same
   //data for each cube so we just define one set of data
   IndexedQuadArray indexedCube = new IndexedQuadArray(8,
       IndexedQuadArray.COORDINATES | IndexedQuadArray.NORMALS, 24);
   Point3f[] cubeCoordinates = { new Point3f(1.0f, 1.0f, 1.0f),
       new Point3f(-1.0f, 1.0f, 1.0f),
       new Point3f(-1.0f, -1.0f, 1.0f),
       new Point3f(1.0f, -1.0f, 1.0f), new Point3f(1.0f, 1.0f, -1.0f),
       new Point3f(-1.0f, 1.0f, -1.0f),
       new Point3f(-1.0f, -1.0f, -1.0f),
       new Point3f(1.0f, -1.0f, -1.0f) };
   Vector3f[] cubeNormals = { new Vector3f(0.0f, 0.0f, 1.0f),
       new Vector3f(0.0f, 0.0f, -1.0f),
       new Vector3f(1.0f, 0.0f, 0.0f),
       new Vector3f(-1.0f, 0.0f, 0.0f),
       new Vector3f(0.0f, 1.0f, 0.0f), new Vector3f(0.0f, -1.0f, 0.0f) };
   int cubeCoordIndices[] = { 0, 1, 2, 3, 7, 6, 5, 4, 0, 3, 7, 4, 5, 6, 2,
       1, 0, 4, 5, 1, 6, 7, 3, 2 };
   int cubeNormalIndices[] = { 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3,
       3, 3, 4, 4, 4, 4, 5, 5, 5, 5 };
   indexedCube.setCoordinates(0, cubeCoordinates);
   indexedCube.setNormals(0, cubeNormals);
   indexedCube.setCoordinateIndices(0, cubeCoordIndices);
   indexedCube.setNormalIndices(0, cubeNormalIndices);
   //Create the three cubes
   leftCube = new Shape3D(indexedCube, app1);
   rightCube = new Shape3D(indexedCube, app2);
   moveCube = new Shape3D(indexedCube, app3);
   //Define some user data so that we can print meaningful messages
   leftCube.setUserData(new String("left cube"));
   rightCube.setUserData(new String("right cube"));
   //Create the content branch and add the lights
   BranchGroup contentBranch = new BranchGroup();
   addLights(contentBranch);
   //Set up the transform to position the left cube
   Transform3D leftGroupXfm = new Transform3D();
   leftGroupXfm.set(new Vector3d(-1.5, 0.0, 0.0));
   leftGroup = new TransformGroup(leftGroupXfm);
   //Set up the transform to position the right cube
   Transform3D rightGroupXfm = new Transform3D();
   rightGroupXfm.set(new Vector3d(1.5, 0.0, 0.0));
   rightGroup = new TransformGroup(rightGroupXfm);
   //Create the movable cube"s transform with a scale and
   //a translation. Set up the
   //capabilities so it can be moved by the behaviour
   Transform3D moveXfm = new Transform3D();
   moveXfm.set(0.7, new Vector3d(0.0, 2.0, 1.0));
   moveGroup = new TransformGroup(moveXfm);
   moveGroup.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
   moveGroup.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
   moveGroup.setCapability(TransformGroup.ENABLE_PICK_REPORTING);
   //Create the behaviour to move the movable cube
   PickTranslateBehavior pickTranslate = new PickTranslateBehavior(
       contentBranch, myCanvas3D, bounds);
   contentBranch.addChild(pickTranslate);
   //Create and add the two colision detectors
   CollisionDetector2 myColDetLeft = new CollisionDetector2(leftCube,
       bounds);
   contentBranch.addChild(myColDetLeft);
   CollisionDetector2 myColDetRight = new CollisionDetector2(rightCube,
       bounds);
   contentBranch.addChild(myColDetRight);
   //Set up the scene graph
   contentBranch.addChild(moveGroup);
   contentBranch.addChild(leftGroup);
   contentBranch.addChild(rightGroup);
   moveGroup.addChild(moveCube);
   leftGroup.addChild(leftCube);
   rightGroup.addChild(rightCube);
   return contentBranch;
 }
 /** Process exit button"s action to quit */
 public void actionPerformed(ActionEvent e) {
   if (e.getSource() == exitButton) {
     dispose();
     System.exit(0);
   }
 }
 public SimpleCollision2() {
   VirtualUniverse myUniverse = new VirtualUniverse();
   Locale myLocale = new Locale(myUniverse);
   myLocale.addBranchGraph(buildViewBranch(myCanvas3D));
   myLocale.addBranchGraph(buildContentBranch());
   setTitle("SimpleWorld");
   setSize(400, 400);
   setLayout(new BorderLayout());
   Panel bottom = new Panel();
   bottom.add(exitButton);
   add(BorderLayout.CENTER, myCanvas3D);
   add(BorderLayout.SOUTH, bottom);
   exitButton.addActionListener(this);
   setVisible(true);
 }
 public static void main(String[] args) {
   SimpleCollision2 sw = new SimpleCollision2();
 }

} /**

* A simple collision detector class. This responds to a collision event by
* printing a message with information about the type of collision event and the
* object involved. This is a variation of the CollisionDetector class that
* prints information about the object that is associated with this behaviour
* rather than the object that has been collided with. An example of its use is
* given in the SimpleCollision2 class.
* 
* @author I.J.Palmer
* @version 1.0
* @see CollisionDetector
* @see SimpleCollision2
*/

class CollisionDetector2 extends Behavior {

 /** The shape that is being watched for collisions. */
 protected Shape3D collidingShape;
 /** The separate criteria that trigger this behaviour */
 protected WakeupCriterion[] theCriteria;
 /** The result of the "OR" of the separate criteria */
 protected WakeupOr oredCriteria;
 /**
  * @param theShape
  *            Shape3D that is to be watched for collisions.
  * @param theBounds
  *            Bounds that define the active region for this behaviour
  */
 public CollisionDetector2(Shape3D theShape, Bounds theBounds) {
   collidingShape = theShape;
   setSchedulingBounds(theBounds);
 }
 /**
  * This sets up the criteria for triggering the behaviour. It creates an
  * entry, exit and movement trigger, OR"s these together and then sets the
  * OR"ed criterion as the wake up condition.
  */
 public void initialize() {
   theCriteria = new WakeupCriterion[3];
   WakeupOnCollisionEntry startsCollision = new WakeupOnCollisionEntry(
       collidingShape);
   WakeupOnCollisionExit endsCollision = new WakeupOnCollisionExit(
       collidingShape);
   WakeupOnCollisionMovement moveCollision = new WakeupOnCollisionMovement(
       collidingShape);
   theCriteria[0] = startsCollision;
   theCriteria[1] = endsCollision;
   theCriteria[2] = moveCollision;
   oredCriteria = new WakeupOr(theCriteria);
   wakeupOn(oredCriteria);
 }
 /**
  * This is where the work is done. This identifies the type of collision
  * (entry, exit or movement) and prints a message stating that an object has
  * collided with this object. The userData field of the shape associated
  * with this collision detector # is used to identify the object. Finally,
  * the wake up condition is set to be the OR"ed criterion again.
  */
 public void processStimulus(Enumeration criteria) {
   while (criteria.hasMoreElements()) {
     WakeupCriterion theCriterion = (WakeupCriterion) criteria
         .nextElement();
     if (theCriterion instanceof WakeupOnCollisionEntry) {
       System.out.println("Collided with "
           + collidingShape.getUserData());
     } else if (theCriterion instanceof WakeupOnCollisionExit) {
       System.out.println("Stopped colliding with  "
           + collidingShape.getUserData());
     } else {
       System.out.println("Moved whilst colliding with "
           + collidingShape.getUserData());
     }
   }
   wakeupOn(oredCriteria);
 }

}


      </source>
   
  
 
  



Tick Tock Collision

   <source lang="java">

/*

* @(#)TickTockCollision.java 1.16 02/10/21 13:58:00
* 
* Copyright (c) 1996-2002 Sun Microsystems, Inc. All Rights Reserved.
* 
* 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.
*  - Redistribution 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 Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
* 
* This software is provided "AS IS," without a warranty of any kind. ALL
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import java.applet.Applet; import java.awt.BorderLayout; import java.awt.GraphicsConfiguration; import java.util.Enumeration; import javax.media.j3d.Alpha; import javax.media.j3d.Appearance; import javax.media.j3d.Background; import javax.media.j3d.Behavior; import javax.media.j3d.BoundingSphere; import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.ColoringAttributes; import javax.media.j3d.Group; import javax.media.j3d.QuadArray; import javax.media.j3d.RotationInterpolator; import javax.media.j3d.Shape3D; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.WakeupOnCollisionEntry; import javax.media.j3d.WakeupOnCollisionExit; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Vector3d; import com.sun.j3d.utils.applet.MainFrame; import com.sun.j3d.utils.geometry.ColorCube; import com.sun.j3d.utils.universe.SimpleUniverse; public class TickTockCollision extends Applet {

 private SimpleUniverse u = null;
 public BranchGroup createSceneGraph() {
   // Create the root of the branch graph
   BranchGroup objRoot = new BranchGroup();
   // Create a Transformgroup to scale all objects so they
   // appear in the scene.
   TransformGroup objScale = new TransformGroup();
   Transform3D t3d = new Transform3D();
   t3d.setScale(0.4);
   objScale.setTransform(t3d);
   objRoot.addChild(objScale);
   // Create a bounds for the background and behaviors
   BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0),
       100.0);
   // Set up the background
   Color3f bgColor = new Color3f(0.05f, 0.05f, 0.2f);
   Background bg = new Background(bgColor);
   bg.setApplicationBounds(bounds);
   objScale.addChild(bg);
   // Create a pair of transform group nodes and initialize them to
   // identity. Enable the TRANSFORM_WRITE capability so that
   // our behaviors can modify them at runtime. Add them to the
   // root of the subgraph.
   TransformGroup objTrans1 = new TransformGroup();
   objTrans1.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
   objScale.addChild(objTrans1);
   TransformGroup objTrans2 = new TransformGroup();
   objTrans2.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
   objTrans1.addChild(objTrans2);
   // Create the positioning and scaling transform group node.
   Transform3D t = new Transform3D();
   t.set(0.3, new Vector3d(0.0, -1.5, 0.0));
   TransformGroup objTrans3 = new TransformGroup(t);
   objTrans2.addChild(objTrans3);
   // Create a simple shape leaf node, add it to the scene graph.
   objTrans3.addChild(new ColorCube());
   // Create a new Behavior object that will perform the desired
   // rotation on the specified transform object and add it into
   // the scene graph.
   Transform3D yAxis1 = new Transform3D();
   yAxis1.rotX(Math.PI / 2.0);
   Alpha tickTockAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE
       | Alpha.DECREASING_ENABLE, 0, 0, 5000, 2500, 200, 5000, 2500,
       200);
   RotationInterpolator tickTock = new RotationInterpolator(tickTockAlpha,
       objTrans1, yAxis1, -(float) Math.PI / 2.0f,
       (float) Math.PI / 2.0f);
   tickTock.setSchedulingBounds(bounds);
   objTrans2.addChild(tickTock);
   // Create a new Behavior object that will perform the desired
   // rotation on the specified transform object and add it into
   // the scene graph.
   Transform3D yAxis2 = new Transform3D();
   Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE, 0, 0,
       4000, 0, 0, 0, 0, 0);
   RotationInterpolator rotator = new RotationInterpolator(rotationAlpha,
       objTrans2, yAxis2, 0.0f, (float) Math.PI * 2.0f);
   rotator.setSchedulingBounds(bounds);
   objTrans2.addChild(rotator);
   // Now create a pair of rectangular boxes, each with a collision
   // detection behavior attached. The behavior will highlight the
   // object when it is in a state of collision.
   Group box1 = createBox(0.3, new Vector3d(-1.3, 0.0, 0.0));
   Group box2 = createBox(0.3, new Vector3d(1.3, 0.0, 0.0));
   objScale.addChild(box1);
   objScale.addChild(box2);
   // Have Java 3D perform optimizations on this scene graph.
   objRoot.rupile();
   return objRoot;
 }
 private Group createBox(double scale, Vector3d pos) {
   // Create a transform group node to scale and position the object.
   Transform3D t = new Transform3D();
   t.set(scale, pos);
   TransformGroup objTrans = new TransformGroup(t);
   // Create a simple shape leaf node and add it to the scene graph
   Shape3D shape = new Box(0.5, 5.0, 1.0);
   objTrans.addChild(shape);
   // Create a new ColoringAttributes object for the shape"s
   // appearance and make it writable at runtime.
   Appearance app = shape.getAppearance();
   ColoringAttributes ca = new ColoringAttributes();
   ca.setColor(0.6f, 0.3f, 0.0f);
   app.setCapability(app.ALLOW_COLORING_ATTRIBUTES_WRITE);
   app.setColoringAttributes(ca);
   // Create a new Behavior object that will perform the collision
   // detection on the specified object, and add it into
   // the scene graph.
   CollisionDetector cd = new CollisionDetector(shape);
   BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0),
       100.0);
   cd.setSchedulingBounds(bounds);
   // Add the behavior to the scene graph
   objTrans.addChild(cd);
   return objTrans;
 }
 public TickTockCollision() {
 }
 public void init() {
   setLayout(new BorderLayout());
   GraphicsConfiguration config = SimpleUniverse
       .getPreferredConfiguration();
   Canvas3D c = new Canvas3D(config);
   add("Center", c);
   // Create a simple scene and attach it to the virtual universe
   BranchGroup scene = createSceneGraph();
   u = new SimpleUniverse(c);
   // This will move the ViewPlatform back a bit so the
   // objects in the scene can be viewed.
   u.getViewingPlatform().setNominalViewingTransform();
   u.addBranchGraph(scene);
 }
 public void destroy() {
   u.cleanup();
 }
 //
 // The following allows TickTockCollision to be run as an application
 // as well as an applet
 //
 public static void main(String[] args) {
   new MainFrame(new TickTockCollision(), 700, 700);
 }

} class CollisionDetector extends Behavior {

 private static final Color3f highlightColor = new Color3f(0.0f, 1.0f, 0.0f);
 private static final ColoringAttributes highlight = new ColoringAttributes(
     highlightColor, ColoringAttributes.SHADE_GOURAUD);
 private boolean inCollision = false;
 private Shape3D shape;
 private ColoringAttributes shapeColoring;
 private Appearance shapeAppearance;
 private WakeupOnCollisionEntry wEnter;
 private WakeupOnCollisionExit wExit;
 public CollisionDetector(Shape3D s) {
   shape = s;
   shapeAppearance = shape.getAppearance();
   shapeColoring = shapeAppearance.getColoringAttributes();
   inCollision = false;
 }
 public void initialize() {
   wEnter = new WakeupOnCollisionEntry(shape);
   wExit = new WakeupOnCollisionExit(shape);
   wakeupOn(wEnter);
 }
 public void processStimulus(Enumeration criteria) {
   inCollision = !inCollision;
   if (inCollision) {
     shapeAppearance.setColoringAttributes(highlight);
     wakeupOn(wExit);
   } else {
     shapeAppearance.setColoringAttributes(shapeColoring);
     wakeupOn(wEnter);
   }
 }

} class Box extends Shape3D {

 public Box(double xsize, double ysize, double zsize) {
   super();
   double xmin = -xsize / 2.0;
   double xmax = xsize / 2.0;
   double ymin = -ysize / 2.0;
   double ymax = ysize / 2.0;
   double zmin = -zsize / 2.0;
   double zmax = zsize / 2.0;
   QuadArray box = new QuadArray(24, QuadArray.COORDINATES);
   Point3d verts[] = new Point3d[24];
   // front face
   verts[0] = new Point3d(xmax, ymin, zmax);
   verts[1] = new Point3d(xmax, ymax, zmax);
   verts[2] = new Point3d(xmin, ymax, zmax);
   verts[3] = new Point3d(xmin, ymin, zmax);
   // back face
   verts[4] = new Point3d(xmin, ymin, zmin);
   verts[5] = new Point3d(xmin, ymax, zmin);
   verts[6] = new Point3d(xmax, ymax, zmin);
   verts[7] = new Point3d(xmax, ymin, zmin);
   // right face
   verts[8] = new Point3d(xmax, ymin, zmin);
   verts[9] = new Point3d(xmax, ymax, zmin);
   verts[10] = new Point3d(xmax, ymax, zmax);
   verts[11] = new Point3d(xmax, ymin, zmax);
   // left face
   verts[12] = new Point3d(xmin, ymin, zmax);
   verts[13] = new Point3d(xmin, ymax, zmax);
   verts[14] = new Point3d(xmin, ymax, zmin);
   verts[15] = new Point3d(xmin, ymin, zmin);
   // top face
   verts[16] = new Point3d(xmax, ymax, zmax);
   verts[17] = new Point3d(xmax, ymax, zmin);
   verts[18] = new Point3d(xmin, ymax, zmin);
   verts[19] = new Point3d(xmin, ymax, zmax);
   // bottom face
   verts[20] = new Point3d(xmin, ymin, zmax);
   verts[21] = new Point3d(xmin, ymin, zmin);
   verts[22] = new Point3d(xmax, ymin, zmin);
   verts[23] = new Point3d(xmax, ymin, zmax);
   box.setCoordinates(0, verts);
   setGeometry(box);
   setAppearance(new Appearance());
 }

}


      </source>