1     package version09;
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.Dimension;
14    import java.awt.Graphics;
15    import java.awt.event.WindowAdapter;
16    import java.awt.event.WindowEvent;
17    import java.awt.image.BufferedImage;
18    import java.net.URL;
19    import java.util.HashMap;
20    
21    import javax.imageio.ImageIO;
22    import javax.swing.JFrame;
23    import javax.swing.JPanel;
24    
25    public class Invaders extends Canvas {
26      public static final int WIDTH = 640;
27      public static final int HEIGHT = 480;
28      public static final int SPEED = 10;
29      
30      public HashMap sprites;

31      public int posX,posY,vX;

32      public BufferedImage buffer;
33      
34      public Invaders() {
35        sprites = new HashMap();
36        posX = WIDTH/2;

37        posY = HEIGHT/2;

38        vX = 2;
39        buffer = new BufferedImage(WIDTH,HEIGHT, BufferedImage.TYPE_INT_RGB);
40      
41        JFrame ventana = new JFrame("Invaders");
42        JPanel panel = (JPanel)ventana.getContentPane();
43        setBounds(0,0,WIDTH,HEIGHT);
44        panel.setPreferredSize(new Dimension(WIDTH,HEIGHT));
45        panel.setLayout(null);
46        panel.add(this);
47        ventana.setBounds(0,0,WIDTH,HEIGHT);
48        ventana.setVisible(true);
49        ventana.addWindowListener( new WindowAdapter() {
50          public void windowClosing(WindowEvent e) {
51            System.exit(0);
52          }
53        });
54        ventana.setIgnoreRepaint(true);
55        ventana.setResizable(false);
56      }
57      
58      public BufferedImage loadImage(String nombre) {
59        URL url=null;
60        try {
61          url = getClass().getClassLoader().getResource(nombre);
62          return ImageIO.read(url);
63        } catch (Exception e) {
64          System.out.println("No se pudo cargar la imagen " + nombre +" de "+url);
65          System.out.println("El error fue : "+e.getClass().getName()+" "+e.getMessage());
66          System.exit(0);
67          return null;
68        }
69      }
70      
71      public BufferedImage getSprite(String nombre) {
72        BufferedImage img = (BufferedImage)sprites.get(nombre);
73        if (img == null) {
74          img = loadImage("res/"+nombre);
75          sprites.put(nombre,img);
76        }
77        return img;
78      }
79      
80      public void paintWorld() {
81        Graphics g = buffer.getGraphics();
82        g.setColor(getBackground());
83        g.fillRect(0,0,getWidth(),getHeight());

84        g.drawImage(getSprite("bicho.gif"), posX, posY,this);
85        getGraphics().drawImage(buffer,0,0,this);
86      }
87      

88    
89      public void paint(Graphics g) {}
90      public void update(Graphics g) {}
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         paint(getGraphics());
103         try { 
104            Thread.sleep(SPEED);
105         } catch (InterruptedException e) {}
106       }
107     }
108     
109     public static void main(String[] args) {
110       Invaders inv = new Invaders();
111       inv.game();
112     }
113   }
114