ufo_attack.java

一个打飞碟小游戏,界面漂亮

//这是一个用导弹攻击UFO的小游戏
//游戏开始有声音提示，并且显示提示信息
//用户通过点击鼠标开始新游戏
//UFO从游戏界面的顶部不断地产生，并不规则的动作向下方移动
//一旦移动到最下方，游戏即失败
//游戏界面的下部有导弹发射管，游戏者通过点击鼠标发射导弹
//要尽量做到百发百中，因为新导弹的装配需要时间
//如果一枚导弹没有击中，UFO就可能在这段装配时间中移动到底部
//导致游戏失败。
import java.awt.*;
import java.applet.*;
import java.util.*;

public class UFO_Attack extends Applet implements Runnable {

	Image buffer   = null ;	// 临时图象缓存
	Image backdrop = null ; 
	Image bgimg    = null ; 
	Image ufostrip = null ;	// UFO Sequence
	Image missile  = null ; // Misile Sequence
	Image missile_explosion
	               = null ; // 导弹爆炸

	MediaTracker tracker = null ;

	Graphics  buf_g = null ; // Buffer graphics object
	Graphics  bkd_g = null ; // Backdrop graphics object
	Dimension window_size = null;
	Font font ;
	Font font_s ;
	
        AudioClip explosion       = null ;
        AudioClip newufo         = null ;
        AudioClip missile_launch = null ;
//每当在新的UFO产生，导弹发射或者导弹命中时候都会有不同的声音提示

	
        Thread  game      = null ;
	boolean game_over = true ;
	int     mouse_x   = 100 ;
        Rectangle paint_area = new Rectangle() ;
        Rectangle new_area   = new Rectangle() ;

	Launcher L  = null ;
	Missile  M  = null ;
	Vector   UV = new Vector() ;
	Vector   EV = new Vector() ;
	
        int NU    = 1 ;
	int score = 0 ;
	
	Color gunColor;
	Color mColor;
	Color ufoColor;
	Color scoreColor;
	Color bgColor;
	
	public void init() {
	  System.out.println("UFO Attack: A game by Sergio Fanchiotti") ;
	  tracker = new MediaTracker(this) ;

          bgimg = getImage(this.getCodeBase(),"bgimg.gif") ;
	  tracker.addImage(bgimg,0) ;

          ufostrip = getImage(this.getCodeBase(),"ufostrip.gif") ;
	  tracker.addImage(ufostrip,0) ;

          missile  = getImage(this.getCodeBase(),"missile.gif") ;
	  tracker.addImage(missile,0) ;

          missile_explosion = getImage(this.getCodeBase(),"explosionstrip.gif") ;
	  tracker.addImage(missile_explosion,0) ;

	  font   = new Font("Helvetica", Font.BOLD, 24) ;
	  font_s = new Font("Helvetica", Font.BOLD, 14) ;

          // Define the colors to use
	  bgColor    = new Color(0,0,128);
	  gunColor   = new Color(0,88,0);
	  mColor     = new Color(255,255,255);
	  ufoColor   = new Color(255,0,0);
	  scoreColor = new Color(0,0,255);
	}


	public void start() {
	  // Change the cursor改变光标
	  getFrame(this).setCursor(Frame.CROSSHAIR_CURSOR) ;
	  window_size = size();
	  buffer = null;
 	  buffer = createImage(window_size.width, window_size.height);
	  backdrop = null;
 	  backdrop = createImage(window_size.width, window_size.height);

	  buf_g = buffer.getGraphics();
	  buf_g.setColor(bgColor);
	  buf_g.fillRect(0, 0, window_size.width, window_size.height);

         // Display initial message
          set_say_font(font) ;
          set_say_mode(CENTER) ;
          set_say_style(SHADOW) ;
	  say("UFO",10,80) ;
	  say("ATTACK") ;
          set_say_font(font_s) ;
          set_say_style(NORMAL) ;
	  say("") ;
	  say("Click to start") ;
	  say("a game") ;

	  //repaint() ;
	  Graphics g = getGraphics() ;
          g.drawImage(buffer,0,0,this) ;

          // Initialize the launcher
	  mouse_x = window_size.width/2 ; 
          L = new Launcher(this) ;
          L.set_color(gunColor) ;

          // Initialize the missile
          M = new Missile(this) ;
          M.set_color(mColor) ;
		

          // Load the sound files now
	  if (explosion == null) 
	    explosion = getAudioClip(getCodeBase(),"explosion.au") ;

	  if (newufo == null) 
	    newufo    = getAudioClip(getCodeBase(),"sonar.au") ;

	  if (missile_launch == null) 
	    missile_launch = getAudioClip(getCodeBase(),"rocket.au") ;

	  game_over = true ;
//演奏声音
          newufo.play() ;         // Play sounds
	  missile_launch.play() ;
	  explosion.play() ;
	}


	public void stop() {
	  // Stop the game if running 
	  if (game != null) {
	    game.stop() ;
	    game = null ; // and eliminate the thread
	  }
	  // Reset the cursor
	  getFrame(this).setCursor(Frame.DEFAULT_CURSOR) ;
	}


        // The main game thread
	public void run() {
	  // Define some local variables
	  UFO  U ;
	  Explosion  E ;
	  long count = 0 ;
          long ti    = 0 ;
	   
	  // Wait for the images to load
	  Graphics g = getGraphics() ;
	  g.setColor(Color.red) ;
	  g.drawString("Starting Game...", 20,20) ;

          while (tracker.checkAll(true) == false) { 
	    if ((ti++ % 2) == 0) 
	      g.setColor(Color.red) ;
	    else 
	      g.setColor(Color.green) ;

	    g.drawString("*", 10,22) ;
            try {Thread.sleep(50);} catch (InterruptedException e) { } ;

	    if (ti > 1000) break ;
	  }
	  
          if (tracker.isErrorAny()) {
	    showStatus("Error getting images") ;
            return ;
	  }
	  showStatus("Loading completed") ;
	  g.dispose() ;


          // Paint the backdrop buffer
	  buf_g = backdrop.getGraphics();
          buf_g.drawImage(bgimg,0,0,window_size.width,window_size.height,this) ;
          // Paint the screen
	  buf_g = getGraphics();
          buf_g.drawImage(backdrop,0,0,this) ;
          // Paing the buffer
	  buf_g = buffer.getGraphics();
          buf_g.drawImage(bgimg,0,0,window_size.width,window_size.height,this) ;

          // Display the buffer
	  repaint() ;

          // Display the initial setup
	  display_score() ;
	  L.draw() ;
          showStatus("UFO ATTACK") ;

	  // Action loop
          for (;;) {
	    ti = System.currentTimeMillis() ;
	    //如果有足够的空间容纳更多的UFO，试着随机性的增加一个
	    if ((UV.size() < NU) && 
	        (Math.random() > (UV.size() == 0 ? 0.90 : 0.98))) {
              newufo.play() ;  // Play a bell 
	      U = new UFO(this) ; 
              U.set_color(ufoColor) ;

              // Set the UFO to fast descent if:
	      if (score > 10 && Math.random() > 0.7) U.vy -= 1 ;

              // Add UFO to the list
	      UV.addElement(U) ;
	    }

	    //在背景上面绘制爆炸的图象，并在结束的时候消除它
	    for (int j=EV.size()-1; j>=0 ; --j) {
	      E = (Explosion) EV.elementAt(j) ;
	      if (E.active) {
	        E.draw() ;
              }
              else {
	        // System.out.println("Ending Explosion " + j) ;
	        E.erase() ;
		EV.removeElementAt(j) ;
	      }
	    }
	  
	    // Move the launcher and the missile
	    L.move() ;
	    if (M.active() == true) M.move() ;

            // Move each UFO
	    for (int i=0; i < UV.size(); ++i) {
	      U = (UFO) UV.elementAt(i) ;
	      U.move() ;
	    }
            // Check for collision between UFO and missile
	    for (int i=(UV.size()-1); i >=0 ; --i) {
	      U = (UFO) UV.elementAt(i) ;
	      if (U.active() && M.active() && U.collision(M)) {
		++score ;
	        explosion.stop() ; 
		display_score() ;
	        explosion.play() ; 

                // Increase the max # of UFOs every 10 destroyed
		// till we reach a max of 5 attacking
	        if ((NU < 5) && (score % 10) == 1)  ++NU ;

                // Erase the missile and deactivate it
	        M.active(false) ;
		M.erase() ;

                // Erase and deactivate the UFO hit
		U.active(false) ;
		U.erase() ;

		// Display an explosion
		E = new Explosion(this,U.px,U.py) ;
	        // System.out.println("Adding Explosion") ;
		EV.addElement(E) ;
	      }

              // Draw the UFO or eliminate it from the list
	      if (U.active()) 
	        U.draw() ;
              else 
	        UV.removeElementAt(i) ;

              // If a UFO reaches the floor then you've lost
              if ((U.py - U.h/2) <=0) {
	        game_over = true ;
		display_game_over() ;
		return ;
	      }
	    }

            // If the launcher moves... redraw
	    if (L.has_moved() || ((M.py-M.h) < (L.py+L.h)) || (! M.active()) )
	      L.draw() ;

            // If active redraw the missile
	    if (M.active() == true) M.draw() ;


            // Make the loop last 20ms in case the CPU is too fast...
            ti = System.currentTimeMillis() - ti ;
	    ti = 20 - ti ; 
	    ti = ti > 0 ?  10 + ti : 10 ; // At least sleep por 10ms
            Thread.yield() ; // Let the GC work?
            try {Thread.sleep(ti);} catch (InterruptedException e) { } ;

            // Repaint every 100 cycles... just in case
	    if ((count = ++count % 500) == 0) {
	      repaint() ;
              // g.drawImage(buffer,0,0,this) ;
	    }
	  }
	}
//显示战绩
//
	public void display_score() {
          Graphics bkd_g = backdrop.getGraphics();
          bkd_g.clipRect(window_size.width/2, 0, window_size.width/2, 40);
          bkd_g.drawImage(bgimg,0,0,window_size.width,window_size.height,this) ;

          bkd_g.setColor(Color.red) ;
          bkd_g.setFont(font) ;
	  String aux = score > 9 ? "" : "0" ;
          bkd_g.drawString(aux+score, window_size.width - 60,30) ;
          bkd_g.dispose() ;

          Graphics bg = buffer.getGraphics() ;
          bg.clipRect(0, 0, window_size.width, 40);
          bg.drawImage(backdrop,0,0,this) ;
          bg.dispose() ;
          // bg = null ;

          Graphics g = getGraphics() ;
          g.clipRect(0, 0, window_size.width, 40);
          g.drawImage(buffer,0,0,this) ;
          g.dispose() ;
          // g = null ;
	}

	public void display_game_over() {
          set_say_font(font) ;
          set_say_mode(CENTER) ;
          set_say_style(SHADOW) ;
	  set_say_pos(10,80) ;
	  say("GAME OVER") ;
          set_say_font(font_s) ;
          set_say_style(NORMAL) ;
	  say("(click to start)") ;
	  repaint() ;
          try {Thread.sleep(500);} catch (InterruptedException e) { } ;
	}

	public boolean mouseMove(Event e, int x, int y) {
	  // showStatus("mouse at: (" + x + ", " + y + ")");
	  mouse_x = x ;
	  return true;
	}

        // Capture the mouse clicks
	public boolean mouseDown(Event e, int x, int y) {
	  if (game_over) {
	    game_over = false ;
	    if (game != null) {
	      game.stop() ;
	      game = null ;
	    }
	    NU    = 1 ;
	    score = 0 ;
	    M.active(false) ;
	    UV.removeAllElements() ;
	    EV.removeAllElements() ;

	    game  = new Thread(this) ;
	    game.setPriority(Thread.MIN_PRIORITY) ;
	    game.start() ;

	    buf_g.dispose() ;

	    return true ;
	  }

	  if (M != null && ! M.active()) {
	    missile_launch.stop() ;
	    missile_launch.play() ;
	    M.set_pos(L.px,L.py) ;
	    M.active(true) ;
	  }

	  return true;
	}

	
	// The paint methos just draws the buffer
	public void paint(Graphics g) {
 	  if (buffer != null) g.drawImage(buffer, 0, 0, this);
	}

        // Makes an animation smoother
	public void update(Graphics g) { 
	  paint(g) ; 
	}

        // Get the Frame of this applet
        public Frame getFrame(Component c) {
          while( c != null && !(c instanceof java.awt.Frame) )
                c = c.getParent();
          return (Frame) c;
        }


        // Text Display Constants
        public static final int CENTER = 1 ;  // Modes: Centered
        public static final int LEFT   = 2 ;  //        Left Justified
        public static final int RIGHT  = 3 ;  //        Right Justified
        public static final int FREE   = 0 ;  //        At x,y

        public static final int NORMAL = 0 ;  // Styles: Normal
        public static final int SHADOW = 1 ;  //         Shadowed 

        // Text Display Variables
        private int  say_pos_y   =  0 ;
        private int  say_pos_x   =  0 ;
        private int  say_mode    = -1 ;
        private int  say_style   = -1 ;
        private int  say_margin  = 10 ;
        private Font say_font    = null ;

        // Text Print Methods
	public void say(String s, int x, int y) {
	  set_say_pos(x, y) ;
	  say(s) ;
	}

	public void say(String s) {
	  FontMetrics fm = getFontMetrics(say_font) ;

          // Compute the x position
	  switch(say_mode) {
	    case CENTER:
	      say_pos_x = (window_size.width - fm.stringWidth(s))/2 ;
	      break ;
	    case RIGHT:
	      say_pos_x = window_size.width - fm.stringWidth(s) - say_margin ;