gamecanvas.java

一个非常好的赛车游戏代码

import java.util.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class GameCanvas extends Canvas
{
  private final int DELAY = 100;
  private final int ROAD_WIDTH = 70;
  private final int INIT_ENERGY = 100;
  private final int COLLIDE_ENERGY = 5;

  private Game game;
  private Form form;
  private GameThread thread;
  private boolean running;
  private boolean finished;
  private int trackId;
  private Player player;
  private Sprite theweapon;
  private int key;
  private SpriteManager enemyList;
  private SpriteManager powerUpsWeapon;
  private SpriteManager powerUpsMoney;
  private int length;
  private long enemyspeed;
  private long myspeed = 0;
  private long line;
  private int timer;
  private boolean weaponon = false;
  private int weaponcount = 0;
  private Weapon weapon;

  private Image scene = Image.createImage(getWidth(),
      getHeight());
  private Graphics g = scene.getGraphics();

  public GameCanvas(Game midlet, Form form)
  {
    game = midlet;
    this.form = form;
    Cache.width = getWidth();
    Cache.height = getHeight();
    try
    {
      player = new Player(Cache.carImage, Cache.carImage.getWidth()/2,
          Cache.carImage.getHeight(), 2, INIT_ENERGY);
      player.setX(Float.createFloat((Cache.width - player.getWidth()) / 2));
      player.setY(Float.createFloat(Cache.height - (player.getHeight() *2)));
      player.setVisible(true);

      // Use weapon 0 for now
      weapon = game.cs.getWeapons()[0];
      theweapon = new Sprite(Cache.flameImage,10,14, 2);
      theweapon.setX(Float.createFloat((Cache.width - player.getWidth()) / 2));
      theweapon.setY(Float.createFloat(Cache.height - (player.getHeight() *2) - 14));
      theweapon.setVisible(true);
    } 
    catch (Exception ex) 
    {
       System.out.println("Problem Creating Sprites!");
       System.err.println(ex);
    }
  }
  
  public void initEnemies()
  {
    line = - Float.createFloat(length);
    timer = 0;
    enemyList = new SpriteManager(Cache.width, Cache.height);
    int size = length / Cache.height * 4 - 1;
    Random rnd = new Random();
    for (int i = 1; i <= size; i++)
    {
      try
      {
        Sprite sprite = new Sprite(Cache.enemyImage,
            Cache.enemyImage.getWidth(), Cache.enemyImage.getHeight(), 1);
        // Figure out where the enemy starts
        int x = rnd.nextInt() % (ROAD_WIDTH -
            Cache.enemyImage.getWidth());
        x = (x < 0 ? -x : x);
        // Draw at a random X
        sprite.setX(Float.createFloat((Cache.width - ROAD_WIDTH) / 2 + x));
        // Scatter the enemy's Y position
        sprite.setY(Float.createFloat(- i * Cache.height / 4));
        // Modify the speed slightly
        x = rnd.nextInt() % 1000;
        long veer = Float.createFloat(0,x);
        long newspeed = Float.add(veer,enemyspeed);
        sprite.setVy(newspeed);
        // Move the enemy back and forth
        x = rnd.nextInt() % 2;
        long sidemove = Float.createFloat(x);
        sprite.setVx(sidemove);
        enemyList.addSprite(sprite);
      } catch (Exception ex) {}
    }
  }
  
  

  public void initPowerups()
  {
    powerUpsMoney = new SpriteManager(Cache.width, Cache.height);
    powerUpsWeapon = new SpriteManager(Cache.width, Cache.height);
    int size = length / Cache.height * 4 - 1;
    Random rnd = new Random();
    boolean formoney = true;
    for (int i = 1; i <= size; i++)
    {
      // The number of power ups a third the number of enemies.
      // That seems fair!
      // So we will only deal with one out of every four...
      if (i % 3 != 0) 
          continue;
      try
      {
        Sprite sprite = new Sprite(Cache.powerupImage,Cache.powerupImage.getWidth(), Cache.powerupImage.getHeight(), 1);
        // Figure out how where to put it...
        int x = rnd.nextInt() % (ROAD_WIDTH - Cache.enemyImage.getWidth());
        x = (x < 0 ? -x : x);
        // Draw at a random X
        sprite.setX(Float.createFloat((Cache.width - ROAD_WIDTH) / 2 + x));
        // Scatter the power ups Y position
        sprite.setY(Float.createFloat(- i * Cache.height / 4));
        // Alternate weapons and money
        if (!formoney)
           powerUpsWeapon.addSprite(sprite);
        else
           powerUpsMoney.addSprite(sprite);
        formoney = !formoney;
      } catch (Exception ex) {}
    }
  }

  public void setSpeed(long speed)
  {
    enemyspeed = speed;
  }

  public void setLength(int length)
  {
    this.length = length;
  }

  public void setTrack(int trackId)
  {
    this.trackId = trackId;
  }

  public void start()
  {
    running = true;
    finished = false;
    thread = new GameThread();
    thread.start();
  }

  public void stop()
  {
    running = false;
  }

  public void keyPressed(int keyCode)
  {

    key = getGameAction(keyCode);
    // When the fire key is pressed, trigger the weapon.
    if (key == FIRE)
    {
      if (!weaponon && weapon.fire())
      {
	  weaponon = true;
          weaponcount = 0;
      }
    }
  }

  public void keyReleased(int keyCode)
  {
    key = 0;
  }

  public void pointerPressed(int x, int y)
  {
    if (x < Cache.width / 2)
        key = LEFT;
    else
        key = RIGHT;
  }

  public void pointerReleased(int x, int y)
  {
    key = 0;
  }

  public void paint(Graphics gr)
  {
    g.setColor(0xffffff);
    g.fillRect(0, 0, Cache.width, Cache.height);
    g.setColor(0x000000);
    g.setStrokeStyle(Graphics.DOTTED);
    g.drawLine(getWidth() / 2, 0, getWidth() / 2,
        getHeight() - 1);
    g.setStrokeStyle(Graphics.SOLID);
    g.fillRect(0, 0, (getWidth() - ROAD_WIDTH) / 2,
        getHeight());
    g.fillRect((getWidth() + ROAD_WIDTH) / 2, 0,
        (getWidth() - ROAD_WIDTH) / 2, getHeight());
    g.drawLine((getWidth() - ROAD_WIDTH) / 2, (int)Float.getInteger(line),
        (getWidth() + ROAD_WIDTH) / 2, (int)Float.getInteger(line));
    // paint power ups first since they are on the ground
    powerUpsMoney.paint(g);
    powerUpsWeapon.paint(g);
    // Then paint other things
    enemyList.paint(g);
    // animate the car
    try {
    player.setFrame(1-player.getFrame());
    }  
    catch (Exception e) { }
    player.paint(g);
    // Draw the weapon
    theweapon.setX(player.getX());
    if (weaponon)
    {
           // Draw flame in front
           if (weapon.getWeaponType() == Weapon.FLAME)
             theweapon.setVisible(true);
           // See if the weapon should be switched off
           if (++weaponcount > weapon.getWeaponTime())
           {
              weaponon = false;
              theweapon.setVisible(false);
           }
           theweapon.paint(g);
    }
    g.drawString("E:" + player.getEnergy(), (getWidth() - ROAD_WIDTH) /
        2 + 1, 0, Graphics.TOP | Graphics.LEFT);
    g.drawString("T:" + (timer / 10) + "." + (timer % 10) + "s",
        getWidth() / 2 + 1, 0, Graphics.TOP | Graphics.LEFT);
    if (weapon != null)
    {
      g.drawString(weapon.getDisplayName(), (getWidth() - ROAD_WIDTH) /
        2 + 1, 15, Graphics.TOP | Graphics.LEFT);
    }
    g.drawString("$"+game.cs.getCash(), (getWidth() - ROAD_WIDTH) / 2 + 1, 30, Graphics.TOP | Graphics.LEFT);
    gr.drawImage(scene, 0, 0, Graphics.TOP | Graphics.LEFT);
  }

  private void moveSprites()
  {
    switch (key)
    {
      case Canvas.LEFT:
          if (Float.getInteger(player.getX()) >
              (Cache.width - ROAD_WIDTH) / 2)
              player.setX(Float.sub(player.getX(),
              Float.createFloat(2)));
          break;
      case Canvas.RIGHT:
          if (Float.getInteger(player.getX()) + player.getWidth() <
              (Cache.width + ROAD_WIDTH) / 2)
              player.setX(Float.add(player.getX(),
              Float.createFloat(2)));
          break;
      case Canvas.UP:
        if (Float.getInteger(myspeed) > 10)
		break;
	myspeed = Float.add(myspeed,1);
        for (int i = 0; i < enemyList.size(); i++)
        {
          Sprite sprite = enemyList.getSprite(i);
          sprite.setVy(Float.add(sprite.getVy(),myspeed));
        }
        break;
      case Canvas.DOWN:
        if (Float.getInteger(myspeed) < -10)
		break;
	myspeed = Float.sub(myspeed,1);
        for (int i = 0; i < enemyList.size(); i++)
        {
          Sprite sprite = enemyList.getSprite(i);
          sprite.setVy(Float.add(sprite.getVy(),myspeed));
        }
        break;
    }
    for (int i = 0; i < enemyList.size(); i++)
    {
      Sprite sprite = enemyList.getSprite(i);
      sprite.setY(Float.add(sprite.getY(), sprite.getVy()));
      // Make sure not hitting the side walls
      sprite.setX(Float.add(sprite.getX(), sprite.getVx()));
      if ((Float.getInteger(sprite.getX()) < (Cache.width - ROAD_WIDTH) / 2) ||
          (Float.getInteger(sprite.getX())  + 
           sprite.getWidth() > (Cache.width + ROAD_WIDTH) / 2))
      {
              // Move in other direction
              sprite.setVx(-sprite.getVx());
      }
    }
    long powerUpSpeed = myspeed;
    if (Float.getInteger(powerUpSpeed) <= 3)
    	powerUpSpeed = Float.createFloat(3);
    for (int i = 0; i < powerUpsWeapon.size(); i++)
    {
      Sprite sprite = powerUpsWeapon.getSprite(i);
      sprite.setY(Float.add(sprite.getY(), powerUpSpeed));
    }
    for (int i = 0; i < powerUpsMoney.size(); i++)
    {
      Sprite sprite = powerUpsMoney.getSprite(i);
      sprite.setY(Float.add(sprite.getY(), powerUpSpeed));
    }
    line = Float.add(line, enemyList.getSprite(0).getVy());
  }

  private void checkCollision()
  {
    // Did enemy hit weapon?
    if (weaponon)
    {
      Sprite collidedwith = enemyList.collideSprite(theweapon);
      // Remove the enemy!
      if (collidedwith != null)
         enemyList.deleteSprite(collidedwith);
    }
    // Did we hit a power up?
    Sprite collidedwith = powerUpsWeapon.collideSprite(player);
    if (collidedwith != null)
    {
    	// Remove the power up
    	powerUpsWeapon.deleteSprite(collidedwith);
        Random rnd = new Random();
        // Add 1 ammo point
        weapon.setWeaponAmmo(weapon.getWeaponAmmo()+1);
    }
    collidedwith = powerUpsMoney.collideSprite(player);
    if (collidedwith != null)
    {
    	// Remove the power up
    	powerUpsMoney.deleteSprite(collidedwith);
        Random rnd = new Random();
        // Add from 5 to 15 dollars
        int x = rnd.nextInt() % 15;
        x = (x < 0 ? -x : x);
        x += 5;
        game.cs.setCash(game.cs.getCash()+x);
    }
    collidedwith = enemyList.collideSprite(player);
    if (collidedwith != null)
        player.setEnergy(player.getEnergy() - COLLIDE_ENERGY);
    if (player.getEnergy() <= 0)
    {
        String vendor = System.getProperty("microedition.platform");
        CrashCarEffect tempclass = null;
        try {
        if( vendor != null && vendor.indexOf( "Siemens" ) != -1 )
          tempclass = (CrashCarEffect)Class.forName("SiemensCrash").newInstance(); 
        else
          tempclass = (CrashCarEffect)Class.forName("DummyCrash").newInstance(); 
        }
        catch (Exception e) { }
        if (tempclass != null)
           tempclass.ICrashed();
        running = false;
    }
  }

  private void checkFinishLine()
  {
    if (Float.getInteger(line) > Cache.height)
    {
      running = false;
      finished = true;
    }
  }

  public class GameThread extends Thread
  {
    public void run()
    {
      while (running)
      {
        long time = System.currentTimeMillis();
        moveSprites();
        checkCollision();
        checkFinishLine();
        timer++;
        repaint();
        serviceRepaints();
        time = System.currentTimeMillis() - time;
        try
        {
          if (time < DELAY)
              Thread.sleep(DELAY - (int)time);
        }
        catch (Exception ex) {}
      }
      String msg = "You Crashed!";
      if (finished)
      {
        // Post the score
        msg = "You finished in time: "+timer+".";
      }
      Alert errorAlert = new Alert("Game Over",msg,null, AlertType.INFO);
      errorAlert.setTimeout(Alert.FOREVER);
      game.getDisplay().setCurrent(errorAlert,form);
    }
  }
}