1     package version11;
2     /**
3      * Curso B?sico de desarrollo de Juegos en Java - Invaders
4      * 
5      * (c) 2004 Planetalia S.L. - Todos los derechos reservados. Prohibida su reproducci?n
6      * 
7      * http://www.planetalia.com
8      * 
9      */
10    
11    
12    import java.awt.Canvas;
13    import java.awt.Color;
14    import java.awt.Dimension;
15    import java.awt.Graphics;
16    import java.awt.event.WindowAdapter;
17    import java.awt.event.WindowEvent;
18    import java.awt.image.BufferStrategy;
19    import java.awt.image.BufferedImage;
20    import java.net.URL;
21    import java.util.HashMap;
22    
23    import javax.imageio.ImageIO;
24    import javax.swing.JFrame;
25    import javax.swing.JPanel;
26    
27    public class Invaders extends Canvas {
28      public static final int WIDTH = 640;
29      public static final int HEIGHT = 480;
30      public static final int SPEED = 10;
31      

32      public BufferStrategy strategy;

33      public HashMap sprites;
34      public int posX,posY,vX;
35      
36      public Invaders() {
37        sprites = new HashMap();
38        posX = WIDTH/2;
39        posY = HEIGHT/2;
40        vX = 2;
41      
42        JFrame ventana = new JFrame("Invaders");
43        JPanel panel = (JPanel)ventana.getContentPane();
44        setBounds(0,0,WIDTH,HEIGHT);
45        panel.setPreferredSize(new Dimension(WIDTH,HEIGHT));
46        panel.setLayout(null);
47        panel.add(this);
48        ventana.setBounds(0,0,WIDTH,HEIGHT);
49        ventana.setVisible(true);
50        ventana.addWindowListener( new WindowAdapter() {
51          public void windowClosing(WindowEvent e) {
52            System.exit(0);
53          }
54        });
55        ventana.setResizable(false);

56        createBufferStrategy(2);
57        strategy = getBufferStrategy();

58        requestFocus();
59      }
60      
61      public BufferedImage loadImage(String nombre) {
62        URL url=null;
63        try {
64          url = getClass().getClassLoader().getResource(nombre);
65          return ImageIO.read(url);
66        } catch (Exception e) {
67          System.out.println("No se pudo cargar la imagen " + nombre +" de "+url);
68          System.out.println("El error fue : "+e.getClass().getName()+" "+e.getMessage());
69          System.exit(0);
70          return null;
71        }
72      }
73      
74      public BufferedImage getSprite(String nombre) {
75        BufferedImage img = (BufferedImage)sprites.get(nombre);
76        if (img == null) {
77          img = loadImage("res/"+nombre);
78          sprites.put(nombre,img);
79        }
80        return img;
81      }
82      
83      public void paintWorld() {

84        Graphics g = strategy.getDrawGraphics();

85        g.setColor(Color.black);
86        g.fillRect(0,0,getWidth(),getHeight());
87        g.drawImage(getSprite("bicho.gif"), posX, posY,this);

88        strategy.show();

89      }
90      
91    
92      
93      public void updateWorld() {
94        posX += vX;
95        if (posX < 0 || posX > WIDTH) vX = -vX;
96      }
97      
98      public void game() {
99        while (isVisible()) {
100         updateWorld();
101         paintWorld();
102         try { 
103            Thread.sleep(SPEED);
104         } catch (InterruptedException e) {}
105       }
106     }
107     
108     public static void main(String[] args) {
109       Invaders inv = new Invaders();
110       inv.game();
111     }
112   }