wrapparticles3d.java

一个用java写的关于粒子系统的小程序

// WrapParticles3D.java
// Andrew Davison, April 2005, [e-mail]

/* Three different implementations of Particle systems:
      * points in a PointArray
      * lines in a LineArray
      * quads in a QuadArray

   Geometrries are stored using BY_REFERENCE, and updated with
   a GeometryUpdater subclass.

   The QuadArray example illustrates how to apply a single texture 
   to each of the quads, and how to blend texture and colour.

   The examples are all variations on a fountain of particles 
   emmitted from the origin in a parabolic arc. Particles are 
   reused when they drop below the XZ plane.
*/


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

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 WrapParticles3D 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 WrapParticles3D(int numParticles, int fountainChoice)
  // construct the 3D canvas
  {
    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);
    canvas3D.requestFocus();    // the canvas now has focus, so receives key events

    su = new SimpleUniverse(canvas3D);

    createSceneGraph(numParticles, fountainChoice);
    initUserPosition();        // set user's viewpoint
    orbitControls(canvas3D);   // controls for moving the viewpoint
    
    su.addBranchGraph( sceneBG );
  } // end of WrapParticles3D()



  private void createSceneGraph(int numParts, int fountainChoice) 
  // 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

    switch(fountainChoice) {
      case 1: addPointsFountain(numParts); break;
      case 2: addLinesFountain(numParts); break;
      case 3: addQuadFountain(numParts); break;
      default: break;   // say nothing
    }

    sceneBG.compile();   // fix the scene
  } // 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()


// -------------------------- fountains -------------


  private void addPointsFountain(int numParts)
  {
    PointParticles ptsFountain = new PointParticles(numParts, 20);   // time delay

    // move particles start position to (2,0,1)
    TransformGroup posnTG = new TransformGroup();
    Transform3D trans = new Transform3D();
    trans.setTranslation( new Vector3d(2.0f, 0.0f, 1.0f) );
    posnTG.setTransform(trans);
    posnTG.addChild(ptsFountain); 
    sceneBG.addChild( posnTG );

    // timed behaviour to animate the fountain
    Behavior partBeh = ptsFountain.getParticleBeh();
    partBeh.setSchedulingBounds( bounds );
    sceneBG.addChild(partBeh);
  } // end of addPointsFountain()


  private void addQuadFountain(int numParts)
  {
    QuadParticles quadsFountain = new QuadParticles(numParts, 20);   // time delay
    sceneBG.addChild(quadsFountain);   // will start at origin

    // timed behaviour to animate the fountain
    Behavior partBeh = quadsFountain.getParticleBeh();
    partBeh.setSchedulingBounds( bounds );
    sceneBG.addChild(partBeh);
  } // end of addQuadFountain()


  private void addLinesFountain(int numParts)
  {
    LineParticles linesFountain = 
				new LineParticles(numParts, 20);   // time delay
    sceneBG.addChild(linesFountain);   // will start at origin

    // timed behaviour to animate the fountain
    Behavior partBeh = linesFountain.getParticleBeh();
    partBeh.setSchedulingBounds( bounds );
    sceneBG.addChild(partBeh);
  } // end of addLinesRefFountain()



} // end of WrapParticles3D class