car.java

这是我们学校教的j2me程序开发实例从入门到精通自带关盘的源代码

package game.entities;

import javax.microedition.m3g.*;

import game.terrain.*;

public class Car
{
  
  static Group carGroup;
  public CarCanvas parent;
  
  public Velocity velocity = new Velocity();  
  
  public float [] carCoords =  new float[3];
                                        
  public static float matrix[]=new float[16];  
  
  private static final float X_POS = 0.0f;
  private static final float Y_POS = 0.01f;
  private static final float Z_POS = 0.0f;

  private static float ANGLE_INCR = 2.0f;   
  public static float MOVE_INCR = 0.0f;

  public boolean upPressed = false;
  public boolean downPressed = false;
  public boolean leftPressed = false;
  public boolean rightPressed = false;

  private Transform trans = new Transform();
  private float[] transMat = new float[16];
  public float xCoord, yCoord, zCoord;
  
  public float xAngle = 0;
  public float yAngle;
  public float zAngle = 0;

  float lol = 0;

  private Group transGroup = new Group();
  private Group group = new Group();
  
  private Camera backcam = new Camera();
  private Camera nosecam = new Camera();
  private Camera sidecam = new Camera();

  public int width;
  public int height;

  Group wheel1;
  Group wheel2;
  Group wheel3;
  Group wheel4;

  Transform tr_cam = new Transform();
  private boolean up_cam = false;
  private boolean down_cam = false;
  static final int UP_CAM = 9;
  static final int DOWN_CAM = 11;
  static final int SHOW_POSITION = 10;
  static final int UP = 1;   //Canvas.UP = UP
  static final int DOWN = 6; //Canvas.DOWN = DOWN
  static final int LEFT = 2; //Canvas.LEFT = LEFT
  static final int RIGHT = 5;//Canvas.RIGHT = RIGHT

  private MobileBackground mobileBackGnd;
  
  private Group floorGroup ;
  private RayIntersection ri = new RayIntersection();
  private final float MAX_HEIGHT =100f;
	
  public void up_cam()
  {
	  backcam.getTransform(tr_cam);
	  tr_cam.postTranslate(0,0.05f,0);
	  backcam.setTransform(tr_cam);
  }
  
  public void down_cam()
  {
	  backcam.getTransform(tr_cam);
	  tr_cam.postTranslate(0,-0.05f,0);
	  backcam.setTransform(tr_cam);
  }
  
  //构造函数
  public Car(int w, int h)
  {
	  width = w;
	  height = h;	  
	  set();
  }
  
  private Group scaleCar = new Group();
  
  public void set()
  {
	  
	    setCamera();
	    
	    setCarEntity();

	    transGroup = new Group();	    
	
	    trans.postTranslate(X_POS, Y_POS, Z_POS);
	    	
	    transGroup.addChild(backcam);
		  
	    transGroup.addChild(nosecam);
		  
	    transGroup.addChild(sidecam);
	    
	    scaleCar.addChild(carGroup);
	    scaleCar.scale(0.5f, 0.5f, 0.5f);
	    transGroup.addChild(scaleCar);
	    transGroup.setTransform(trans);
	    
	    yAngle = 0.0f;

	    wheel1 = (Group) carGroup.find(65);
	    wheel2 = (Group) carGroup.find(69);
	    wheel3 = (Group) carGroup.find(63);
	    wheel4 = (Group) carGroup.find(67);
  }
  
  
  public void setCamera()
  {
	  float aspectRatio = ((float) width) / ((float) height);
	  
	  backcam.postRotate(-20,1,0,0);	  
	  
	  backcam.setTranslation(0,2,4);;
	  
	  backcam.setPerspective(60.0f, aspectRatio, 0.5f, 1000.0f);	

	  nosecam.setPerspective(60.0f,aspectRatio,0.5f,1000);

	  nosecam.setTranslation(0,0.75f,0.25f);
	  
	  sidecam.setPerspective(60.0f,aspectRatio,0.5f,1000);
	    
	  sidecam.setTranslation(-2,0.75f,2.5f);
	    
	  sidecam.postRotate(-45,0,1,0);
  }
  

  public void setCarEntity()
  {
	  World carw = loadWorld("/models/car.m3g");
	  carGroup = (Group) carw.find(62);
	  carw.removeChild(carGroup);
  }
  
//载入World
  public World loadWorld(String fn)
  {
    Object3D[] tile = load(fn);
    World w = null;
    for (int i = 0; i < tile.length; i++){
      try{
        w = (World)tile[i];
        break;
      }catch(Exception ex){
      }
    }
    return w;
  }
  
  //载入3DObject
  public Object3D[] load( String fn ){
    Object3D[] obj = null;
    try {
      obj = Loader.load(fn);
    } catch(Exception e) {
      e.printStackTrace();
    }
    return obj;
  }
  
  public Group getCameraGroup()
  { 
    return transGroup;
  }
  
  public Group getObjectGroup()
  {  
	return group;
  }

  //获取照相机
  public Camera getBackCamera()
  {  
	  return backcam;
  }

	public Camera getNoseCamera() {	
		return nosecam;
	}

	public Camera getSideCamera() {		
		return sidecam;
	}
	
  //响应键盘(按下)
  public void pressedKey(int gameAction){
	
    switch(gameAction) {
    
      case UP_CAM:          up_cam = true;       break;
      case DOWN_CAM:        down_cam = true;     break;
      case UP: 			    upPressed = true;	 break;
      case DOWN:			downPressed = true;  break;
      case LEFT:			leftPressed = true;	 break;
      case RIGHT:			rightPressed = true; break;    
      default: 									 break;
      
    }
  }

  //响应键盘(释放)
  public void releasedKey(int gameAction){
    switch(gameAction) {
    
      case UP_CAM:          up_cam = false;       break;
      case DOWN_CAM:        down_cam = false;     break;
      case UP: 			    upPressed = false;	  break;
      case DOWN:			downPressed = false;  break;
      case LEFT:			leftPressed = false;  break;
      case RIGHT:			rightPressed = false; break;
      default: 									  break;
    }
  }

  //响应键盘,移动汽车
  public void update(){	  
	  
	  try {
		Thread.sleep(1);
	} catch (InterruptedException e) {		
		e.printStackTrace();
	}
	
	    if( up_cam )
	    {
	    	up_cam();    	
	    }
	    if( down_cam )
	    {
	    	down_cam();
	    }	    
	    
    transGroup.getTransform(trans);
    
    getPosition();
    
    if (upPressed){    	
        if (MOVE_INCR >= 0)
          MOVE_INCR = velocity.accelerate();
        else if (MOVE_INCR < 0)
          MOVE_INCR = -velocity.brake(20);        
      }
    else if (downPressed){    	
        if (MOVE_INCR <= 0){
          MOVE_INCR = -velocity.accelerate();
        }else if (MOVE_INCR > 0){
          MOVE_INCR = velocity.brake();
        }        
      }else{
        if (MOVE_INCR >= 0)
          MOVE_INCR = velocity.brake(60);
        else
          MOVE_INCR = -velocity.brake(60);
      }
    
    if (MOVE_INCR != 0)    	
    {
    	if(leftPressed || rightPressed)
    		updateYaw();
    }
    updateMove();    
   
    backcam.setTranslation(lol,2.5f,4);

    float f[] = new float[4];
    wheel2.getOrientation(f);
    
    if(leftPressed){
      if (lol > -1)
        lol = lol - 0.1f;
     
      if (f[0] < 140) {
        wheel1.postRotate( -5, 0, 0, 1);
        wheel2.postRotate( -5, 0, 0, 1);
      }
    }else if(rightPressed){
      if (lol < 1)
        lol = lol + 0.1f;
      if (f[0] > 100) {
        wheel1.postRotate(5, 0, 0, 1);
        wheel2.postRotate(5, 0, 0, 1);
      }
    }else{
      if (lol < -0.1f)
        lol = lol + 0.1f;
      else if (lol > 0.1f)
        lol = lol - 0.1f;
      else
        lol = 0;

      if (f[0] > 119.99975f) {
        wheel1.postRotate(5, 0, 0, 1);
        wheel2.postRotate(5, 0, 0, 1);
      }else if (f[0] < 119.99975f) {
        wheel1.postRotate( -5, 0, 0, 1);
        wheel2.postRotate( -5, 0, 0, 1);
      }
    }      

    wheel1.getChild(0).postRotate(-MOVE_INCR * 100,0,1,0);
    wheel2.getChild(0).postRotate(-MOVE_INCR * 100,0,1,0);
    wheel3.getChild(0).postRotate(-MOVE_INCR * 100,0,1,0);
    wheel4.getChild(0).postRotate(-MOVE_INCR * 100,0,1,0);

    terrainCheck();
  }
  
  //更新汽车的移动位置
  public void updateMove(){
    trans.postTranslate(0, 0, -MOVE_INCR);
  }

  //更新汽车的偏移角
  public void updateYaw(){
    if (leftPressed) {
      yAngle += ANGLE_INCR;
    }else if (rightPressed){
      yAngle -= ANGLE_INCR;
    }

    if (yAngle >= 360.0f)
      yAngle -= 360.0f;
    else if (yAngle < -360.0f)
      yAngle += 360.0f;

    storePosition();
    trans.setIdentity();

    trans.postTranslate(xCoord, yCoord, zCoord);
    trans.postRotate(yAngle, 0, 1.0f, 0);
    
    if( rightPressed )
    {
    	mobileBackGnd.moveLeft(1);
    }else{
    	mobileBackGnd.moveRight(1);
    }
  }

  //获得汽车的位置坐标
  public float[] getPosition(){
    storePosition();
    return new float[] { xCoord, yCoord, zCoord };
  }

  //存储汽车的位置坐标
  private void storePosition(){
    transGroup.getCompositeTransform(trans);
    trans.get(transMat);
    xCoord = transMat[3];
    yCoord = transMat[7];
    zCoord = transMat[11];
  }
  
  public float[] getAngle()
  {
	   return new float[] {xAngle,yAngle,zAngle};
  }
  
   //得到汽车的偏移角（和z轴负方向之间）
   public float getYAngle()
   {
	  return yAngle;
   }

	public String toString() {		
		return super.toString();
	}
			
	public void addCollisionGroup(Group _collisionGroup) {
		floorGroup = _collisionGroup;				
	}
	
	public void setParent(CarCanvas top)
	{
		parent = top;
	}
	
	//地形跟随
	private void terrainCheck()
	{	
		//transGroup.setTransform(trans);需要连着调用两次,
		//第一次调用前,得到了汽车下次的坐标,
		//第二次调用前,进行汽车Y坐标的调整
		transGroup.setTransform(trans);
		
		storePosition();
		
		//如发现与地形MESH相交，则进行地形跟随
		if (	floorGroup.pick(-1, 
						xCoord, 
						MAX_HEIGHT, 
						zCoord,
						0, 
						-1, 
						0,
						ri)  )						
		{
						
			yCoord = MAX_HEIGHT - ri.getDistance();
			
			transMat[7]=yCoord;
			
			trans.set(transMat);
		}
		
		transGroup.setTransform(trans);
	}

//	背景只平移,不上下移动
	public void addBackGround(MobileBackground mb) {
		mobileBackGnd = mb ;
	}
}