wrapflocking3d.java

一个模拟鸟群飞行的3D程序

// WrapFlocking3D.java
// Andrew Davison, April 2005, [e-mail]
// Sirinart Sakarin, March 2003, [e-mail]

/* The flocking predators and prey are created and added to
   the scene in addFlockingBoids(). Obstacles for the boids are
   also created there.

   The rest of the code is standard. 
*/

import javax.swing.*;
import java.awt.*;
import java.util.*;

import com.sun.j3d.utils.universe.*;
import com.sun.j3d.utils.geometry.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.behaviors.vp.*;


public class WrapFlocking3D extends JPanel
// Holds the 3D canvas where the loaded image is displayed
{
  private static final int PWIDTH = 512;   // size of panel
  private static final int PHEIGHT = 512; 
  private static final int BOUNDSIZE = 100;  // larger than world

  private static final Point3d USERPOSN = new Point3d(0,5,20);
    // initial user position



  private SimpleUniverse su;
  private BranchGroup sceneBG;
  private BoundingSphere bounds;   // for environment nodes



  public WrapFlocking3D(int numPreds, int numPrey, int numObs)
  // A panel holding a 3D canvas: the usual way of linking Java 3D to Swing
  {
    setLayout( new BorderLayout() );
    setOpaque( false );
    setPreferredSize( new Dimension(PWIDTH, PHEIGHT));

    GraphicsConfiguration config =
                    SimpleUniverse.getPreferredConfiguration();
    Canvas3D canvas3D = new Canvas3D(config);
    add("Center", canvas3D);
    canvas3D.setFocusable(true);     // give focus to the canvas 
    canvas3D.requestFocus();

    su = new SimpleUniverse(canvas3D);
    createSceneGraph(numPreds, numPrey, numObs);
    initUserPosition();        // set user's viewpoint
    orbitControls(canvas3D);   // controls for moving the viewpoint
    
    su.addBranchGraph( sceneBG );
  } // end of WrapFlocking3D()


  private void createSceneGraph(int numPreds, int numPrey, int numObs) 
  // initilise the scene
  { 
    sceneBG = new BranchGroup();
    bounds = new BoundingSphere(new Point3d(0,0,0), BOUNDSIZE);   

    lightScene();         // add the lights
    addBackground();      // add the sky
    sceneBG.addChild( new CheckerFloor().getBG() );  // add the floor

    addFlockingBoids(numPreds, numPrey, numObs);
  } // end of createSceneGraph()


  private void lightScene()
  /* One ambient light, 2 directional lights */
  {
    Color3f white = new Color3f(1.0f, 1.0f, 1.0f);

    // Set up the ambient light
    AmbientLight ambientLightNode = new AmbientLight(white);
    ambientLightNode.setInfluencingBounds(bounds);
    sceneBG.addChild(ambientLightNode);

    // Set up the directional lights
    Vector3f light1Direction  = new Vector3f(-1.0f, -1.0f, -1.0f);
       // left, down, backwards 
    Vector3f light2Direction  = new Vector3f(1.0f, -1.0f, 1.0f);
       // right, down, forwards

    DirectionalLight light1 = 
            new DirectionalLight(white, light1Direction);
    light1.setInfluencingBounds(bounds);
    sceneBG.addChild(light1);

    DirectionalLight light2 = 
        new DirectionalLight(white, light2Direction);
    light2.setInfluencingBounds(bounds);
    sceneBG.addChild(light2);
  }  // end of lightScene()


  private void addBackground()
  // A blue sky
  { Background back = new Background();
    back.setApplicationBounds( bounds );
    back.setColor(0.17f, 0.65f, 0.92f);    // sky colour
    sceneBG.addChild( back );
  }  // end of addBackground()


  private void orbitControls(Canvas3D c)
  /* OrbitBehaviour allows the user to rotate around the scene, and to
     zoom in and out. */
  {
    OrbitBehavior orbit = 
        new OrbitBehavior(c, OrbitBehavior.REVERSE_ALL);
    orbit.setSchedulingBounds(bounds);

    ViewingPlatform vp = su.getViewingPlatform();
    vp.setViewPlatformBehavior(orbit);      
  }  // end of orbitControls()



  private void initUserPosition()
  // Set the user's initial viewpoint using lookAt()
  {
    ViewingPlatform vp = su.getViewingPlatform();
    TransformGroup steerTG = vp.getViewPlatformTransform();

    Transform3D t3d = new Transform3D();
    steerTG.getTransform(t3d);

    // args are: viewer posn, where looking, up direction
    t3d.lookAt( USERPOSN, new Point3d(0,0,0), new Vector3d(0,1,0));
    t3d.invert();

    steerTG.setTransform(t3d);
  }  // end of initUserPosition()



  // ---------------------- flocking boids -----------------


  private void addFlockingBoids(int numPreds, int numPrey, int numObs)
  { 
    // create obstacles
    Obstacles obs = new Obstacles(numObs);
    sceneBG.addChild( obs.getObsBG() );  // add obstacles to the scene

    // make the predator manager
    PredatorBehavior predBeh = new PredatorBehavior(numPreds, obs);
    predBeh.setSchedulingBounds(bounds);
    sceneBG.addChild( predBeh.getBoidsBG() );  // add predators to the scene

    // make the prey manager
    PreyBehavior preyBeh = new PreyBehavior(numPrey, obs);
    preyBeh.setSchedulingBounds(bounds);
    sceneBG.addChild( preyBeh.getBoidsBG() );  // add prey to the scene

    // tell behaviours about each other
    predBeh.setPreyBeh( preyBeh );
    preyBeh.setPredBeh( predBeh );

  } // end of addFlockingBoids()


} // end of WrapFlocking3D class