ufo_attack.java

这是个用Java语言编写的游戏小程序 标准目标

	  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 ;
	      break ;
	    case LEFT:
	    default :
	      say_pos_x = say_margin ;
	      break ;
	  }

          Graphics bg = buffer.getGraphics() ;
          bg.setFont(say_font) ;

          // Print style extras
	  if (say_style == SHADOW) {
            bg.setColor(new Color(150,150,150)) ;
            bg.drawString(s, say_pos_x+2,say_pos_y+1) ;
	  }

          // Print string
          bg.setColor(Color.white) ;
          bg.drawString(s, say_pos_x,say_pos_y) ;

          // Shift y position to next line
	  say_pos_y += (int) (1.2 * fm.getHeight()) ;

          // Free some resources
          bg.dispose() ;
	}

	public void set_say_mode(int m) {
	  say_mode = m ;
	}

	public void set_say_style(int s) {
	  say_style = s ;
	}

	public void set_say_font(Font f) {
	  say_font = f ;
	}

	public void set_say_margin(int margin) {
	  say_margin = margin ;
	}

	public void set_say_pos(int x, int y) {
	  say_pos_x = x ;
	  say_pos_y = y ;
	}
}


class Piece {
  UFO_Attack a ;

  int px,py ;
  int opx,opy ;
  int w,h ;
  int vx,vy ;
  Color c ;
  boolean active = false ;
  Image img = null ;

  public void set_pos(int x, int y) {
    px = opx = x ;
    py = opy = y ;
  }

  public void set_vel(int x,int y) {
    vx = x ;
    vy = y ;
  }

  public void set_size(int x,int y) {
    w = x ;
    h = y ;
  }

  public void set_color(Color c) {
    this.c = c ;
  }

  public void set_draw_rectangles(Rectangle o, Rectangle n) {
    int sh = a.window_size.height ; 

    int x  = px - w/2 ;
    int y  = (sh - py) - h/2 ;

    int ox = opx - w/2 ;
    int oy = (sh - opy) - h/2 ;
    
    o.reshape(ox,oy,w,h) ; 
    n.reshape(x,y,w,h) ; 
  }

  public boolean active() {
    return active ;
  }

  public void active(boolean s) {
    active = s ;
  }

  public boolean collision(Piece p) {
    int dpx = Math.abs(px - p.px) ;
    int dpy = Math.abs(py - p.py) ;

    if ((dpx < (Math.max(w/2,p.w/2))+1) && (dpy < (Math.max(h/2,p.h/2)+1))) 
      return true ;

    return false ;
  }

  public void draw() {
    set_draw_rectangles(a.paint_area, a.new_area) ;

    // a.buf_g.setColor(a.bgColor);
    // a.buf_g.fillRect(a.paint_area.x, a.paint_area.y, w, h);

    Graphics bg = a.buffer.getGraphics() ;
    bg.clipRect(a.paint_area.x, a.paint_area.y, w, h);
    bg.drawImage(a.backdrop,0,0,a) ;
    bg.dispose() ;
    // bg = null ;

    a.buf_g.setColor(c);
    a.buf_g.fillRect(a.new_area.x, a.new_area.y, w, h);

    a.paint_area.add(a.new_area) ;

    Graphics g = a.getGraphics() ;
    g.clipRect(a.paint_area.x ,a.paint_area.y, a.paint_area.width, a.paint_area.height);
    g.drawImage(a.buffer, 0, 0, a);
    g.dispose() ;
    // g = null ;
  }

  public void erase() {
    set_draw_rectangles(a.paint_area, a.new_area) ;
    a.paint_area.add(a.new_area) ;

    // Copy the backdrop into the buffer
    Graphics bg = a.buffer.getGraphics() ;
    bg.clipRect(a.paint_area.x, a.paint_area.y, a.paint_area.width, a.paint_area.height);
    bg.drawImage(a.backdrop,0,0,a) ;
    bg.dispose() ;

    // Paint the change into the screen
    Graphics g = a.getGraphics() ;
    g.clipRect(a.paint_area.x,a.paint_area.y,a.paint_area.width,a.paint_area.height);
    g.drawImage(a.buffer,0,0, a);
    g.dispose() ;
  }
}

class Launcher extends Piece {

  public Launcher (UFO_Attack a) {
    this.a = a ; 
    w  = 12 ;
    h  = 22 ;
    px = opx = a.window_size.width/2 ;
    py = opy = w/2+1 ;
    active = true ;
    img = a.missile ;
  }

  public void move() {
    opx = px ;
    opy = py ;

    int dx     = a.mouse_x - px ;
    int abs_dx = Math.abs(dx) ;
    int step = 1 ;

    if (abs_dx > 10) 
      step = 5 ;
    else if (abs_dx > 1)
      step = abs_dx/2 ;

    if (dx != 0) {
      px += step*(dx/abs_dx) ;
      if (px < w/2) 
        px = w/2 ;
      else if (px > (a.window_size.width - w/2)) 
        px = a.window_size.width - w/2 ;
    }
  }

  public boolean has_moved() {
    if ((px - opx) != 0) return true ;

    return false ;
  }

  public void draw() {
    set_draw_rectangles(a.paint_area, a.new_area) ;

    // a.buf_g.setColor(a.bgColor);
    // a.buf_g.fillRect(a.paint_area.x, a.paint_area.y, w, h);

    Graphics bg = a.buffer.getGraphics() ;
    bg.clipRect(a.paint_area.x, a.paint_area.y, w, h);
    bg.drawImage(a.backdrop,0,0,a) ;
    bg.dispose() ;
    // bg = null ;


    if (a.M.active()) {
      a.buf_g.setColor(c);
      a.buf_g.fillRect(a.new_area.x, a.new_area.y, w, h);
    }
    else {
      bg = a.buffer.getGraphics() ;
      bg.clipRect(a.new_area.x, a.new_area.y, w, h);
      bg.drawImage(img,a.new_area.x,a.new_area.y,a) ;
      bg.dispose() ;
      // bg = null ;
    }

    a.paint_area.add(a.new_area) ;

    Graphics g = a.getGraphics() ;
    g.clipRect(a.paint_area.x ,a.paint_area.y, a.paint_area.width, a.paint_area.height);
    g.drawImage(a.buffer, 0, 0, a);
    g.dispose() ;
    // g = null ;
  }

}

class Missile extends Piece {
  public Missile (UFO_Attack a) {
    this.a = a ; 
    px = opx = 0 ;
    py = opy = 0 ;
    vx = 0 ;
    vy = 7 ;
    w  = 12 ;
    h  = 22 ;
    active = false ;

    img = a.missile ;
  }

  public void move() {
    opx = px ;
    opy = py ;

    px = a.L.px ;

    // Try to make the speed more realistic
    int dx = px - opx ;
    int nvy = vy*vy - dx*dx ;
    if (nvy > 0) nvy = (int) Math.sqrt(nvy) ; // Should exceptions
    if (nvy < 1) nvy = 1 ;

    py += nvy ;

    if (py > a.window_size.height + 2*h) active = false ;
  }

  int seq  = 0 ;
  // int seq2 = 0 ;
  public void draw() {
    set_draw_rectangles(a.paint_area, a.new_area) ;

    // a.buf_g.setColor(a.bgColor);
    // a.buf_g.fillRect(a.paint_area.x, a.paint_area.y, w, h);

    Graphics bg = a.buffer.getGraphics() ;
    bg.clipRect(a.paint_area.x, a.paint_area.y, w, h);
    bg.drawImage(a.backdrop,0,0,a) ;
    bg.dispose() ;
    // bg = null ;


    // if ((++seq2 % 4) == 0) seq = ++seq % 1 ;
    int dx = px - opx ;
    seq = 0 ;
    if (dx > 0) 
      seq = 1 ;
    else if (dx < 0)
      seq = 2 ;

    bg = a.buffer.getGraphics() ;
    bg.clipRect(a.new_area.x, a.new_area.y, w, h);
    bg.drawImage(img,a.new_area.x-w*seq,a.new_area.y,a) ;

    bg.dispose() ;
    // bg = null ;

    a.paint_area.add(a.new_area) ;

    Graphics g = a.getGraphics() ;
    g.clipRect(a.paint_area.x ,a.paint_area.y, a.paint_area.width, a.paint_area.height);
    g.drawImage(a.buffer, 0, 0, a);
    g.dispose() ;
    // g = null ;
  }

}

class UFO extends Piece {
  public UFO (UFO_Attack a) {
    this.a = a ; 
    vx = (Math.random() > 0.5 ? 1 : -1) ;
    vy = -2 ;
    w  = 20 ;
    h  = 8 ;
    int aw = a.window_size.width ;
    px = opx =  (int) (w/2+1 + (aw-w-2)* Math.random()) ;
    py = opy = a.window_size.height + h/2 + 1  ;
    active = true ;

    img = a.ufostrip ;
  }

  public void move() {
    opx = px ;
    opy = py ;

    px += vx ;
    py += vy ;

    if (py < -h/2) active = false ;

    if ((px <= w/2) || 
        (px >= (a.window_size.width - w/2)) ||
        (Math.random() > 0.96)) {
      vx = -vx ;
    }
  }

  int seq  = 0 ;
  int seq2 = 0 ;
  public void draw() {
    set_draw_rectangles(a.paint_area, a.new_area) ;

    // Clear the old image
    Graphics bg = a.buffer.getGraphics() ;
    bg.clipRect(a.paint_area.x, a.paint_area.y, w, h);
    bg.drawImage(a.backdrop,0,0,a) ;
    bg.dispose() ;
    // bg = null ;


    // Choose the image sequence (every 4 draws change frame)
    if ((++seq2 % 4) == 0) seq = ++seq % 4 ;

    // Paint new region into buffer
    bg = a.buffer.getGraphics() ;
    bg.clipRect(a.new_area.x, a.new_area.y, w, h);
    bg.drawImage(img,a.new_area.x-w*seq,a.new_area.y,a) ;
    bg.dispose() ;

    // Add old and new areas for updating
    a.paint_area.add(a.new_area) ;

    // Paint changes into screen buffer
    Graphics g = a.getGraphics() ;
    g.clipRect(a.paint_area.x ,a.paint_area.y, a.paint_area.width, a.paint_area.height);
    g.drawImage(a.buffer, 0, 0, a);
    g.dispose() ;
  }
}
	
class Explosion extends Piece {
  public Explosion (UFO_Attack a, int x, int y) {
    this.a = a ; 
    w  = 30 ;
    h  = 30 ;
    px = opx = x ;
    py = opy = y ;
    active = true ;
    img = a.missile_explosion ;
  }

  int seq  = 0 ;
  int seq2 = 0 ;
  public void draw() {
    set_draw_rectangles(a.paint_area, a.new_area) ;

    // Clear the old image
    Graphics bkd_g = a.backdrop.getGraphics();
    bkd_g.clipRect(a.paint_area.x, a.paint_area.y, w, h);
    bkd_g.drawImage(a.bgimg,0,0,a.window_size.width,a.window_size.height,a) ;

    // Choose the image sequence (every 4 draws change frame)
    if ((++seq2 % 4) == 0) seq = ++seq % 5 ;

    // Deactivate after drawing the last explosion frame
    if (seq == 4) active = false ;

    // Paint new region into buffer
    bkd_g.clipRect(a.new_area.x, a.new_area.y, w, h);
    bkd_g.drawImage(img,a.new_area.x-w*seq,a.new_area.y,a) ;
    bkd_g.dispose() ;

    // Paint changes into the buffer
    Graphics bg = a.buffer.getGraphics() ;
    bg.clipRect(a.new_area.x,a.new_area.y,w,h);
    bg.drawImage(a.backdrop,0,0,a) ;
    bg.dispose() ;

    // Paint changes into screen buffer
    Graphics g = a.getGraphics() ;
    g.clipRect(a.paint_area.x ,a.paint_area.y, a.paint_area.width, a.paint_area.height);
    g.drawImage(a.buffer, 0, 0, a);
    g.dispose() ;
  }

  public void erase() {
    set_draw_rectangles(a.paint_area, a.new_area) ;

    // Clear the old image
    Graphics bkd_g = a.backdrop.getGraphics();
    bkd_g.clipRect(a.paint_area.x, a.paint_area.y, w, h);
    bkd_g.drawImage(a.bgimg,0,0,a.window_size.width,a.window_size.height,a) ;
    bkd_g.dispose() ;

    // Do the same for the buffer and the screen
    // It will flicker any UFO on top...
    super.erase() ;
  }
}