Applet tile engine - Java-Gaming.org

I am not trying to make a game with an applet, just do some simple tile rendering things. I have come up with a nice effect, animated tiles too. The only problem is sometimes it loads in my browser and sometimes it does not. I am currenly using firefox, if I open the applet with ie it loads more often but still not all the time. I posted my full source and was wondering if someone can tell me why this is happening. Thanks.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class Tile_engine extends Applet implements KeyListener, Runnable {

  private int keyPressed = -1;
  private int screenX = 0;
  private int screenY = 0; 
  private final int TILE_MAX = 11;
  private final int TILE_SIZE = 32;
  private final int APPLET_WIDTH = 640;
  private final int APPLET_HEIGHT = 480; 
  private final int SKY = 0;
  private final int CLOUD_1 = 1;
  private final int CLOUD_2 = 2;
  private final int RED_BRICKS = 3;
  private final int GRASS = 4;
  private final int DIRT = 5;
  private final int STONE = 6;
  private final int QBOX1 = 7;
  private final int QBOX2 = 8;
  private final int QBOX3 = 9;
  private final int QBOX4 = 10;
  private final int MAP_ROWS = 15;
  private final int MAP_COLS = 65;
  private Image background = null;
  private Image buffer = null;
  private Graphics bgBuff;
  private Graphics bufferg;
  private Image[] tile = new Image[TILE_MAX];

  private final int map[][] = 
    {{0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,6,6,6,6,6,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,0,0,0,0,0},
     {0,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,7,7,7,7,0,0,0,0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,6,6,6,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0},
     {0,0,7,7,7,0,0,0,0,0,0,0,3,3,3,3,0,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,6,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,0,0,3,6,6,0,0,0,0,4,4,4,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,5,0,0,0,0,0,0,0,0,0,3,6,6,0,0,0,0,5,5,5,5,5,5,5,5,5,5,5,0,0,0,0,0,0,0,0,0,0,0},
     {4,4,4,4,4,4,4,4,0,0,4,4,4,4,4,4,4,4,4,4,4,4,0,0,5,0,5,0,0,4,4,4,0,0,0,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,4,4,4,4,6,6,6,4,4,4,4},
     {5,5,5,5,5,5,5,5,0,0,5,5,5,5,5,5,5,5,5,5,5,5,0,0,5,0,5,0,0,5,5,5,0,0,0,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0,0,0,5,5,5,5}};
   
  
  public void init( ) {
    tile[SKY] = getImage(getDocumentBase(), "sky.png");
    tile[CLOUD_1] = getImage(getDocumentBase(), "cloud1.png");
    tile[CLOUD_2] = getImage(getDocumentBase(), "cloud2.png");
    tile[RED_BRICKS] = getImage(getDocumentBase(), "redBricks.png");
    tile[GRASS] = getImage(getDocumentBase(), "grass.png");
    tile[DIRT] = getImage(getDocumentBase(), "dirt.png");
    tile[STONE] = getImage(getDocumentBase(), "stone.png");
    tile[QBOX1] = getImage(getDocumentBase(), "qbox1.png");
    tile[QBOX2] = getImage(getDocumentBase(), "qbox2.png");
    tile[QBOX3] = getImage(getDocumentBase(), "qbox3.png");
    tile[QBOX4] = getImage(getDocumentBase(), "qbox4.png");

    buffer = createImage(TILE_SIZE * MAP_COLS, TILE_SIZE * MAP_ROWS);
    bufferg = buffer.getGraphics();

    addKeyListener(this); 

    if(buffer != null) {
      int tile_id;
      for(int y=0;y<MAP_ROWS;y++) {
        for(int x=0;x<MAP_COLS;x++) {
          tile_id = map[y][x]; 
          bufferg.drawImage(tile[tile_id], x * TILE_SIZE, y * TILE_SIZE, this);
        }
      }
    } 

  }

  public void start( ) {
    Thread th = new Thread(this);
    // start this thread
    th.start(); 
  }

  public void run( ) {
    Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
    while(true) {
      animate_tiles();
    
      try {
   Thread.sleep(200);
      } catch(InterruptedException ex) {
      }
      Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
    } 
  }
  
  public void animate_tiles( ) {
    int tile_id;
    
    for(int y=0;y<MAP_ROWS;y++) {
      for(int x=0;x<MAP_COLS;x++) {
        tile_id = map[y][x]; 
      
        switch(tile_id) {
          case QBOX1: map[y][x] = QBOX2; break;
          case QBOX2: map[y][x] = QBOX3; break;
          case QBOX3: map[y][x] = QBOX4; break;
          case QBOX4: map[y][x] = QBOX1; break;
          default: break; //not needed  
        }
      }
    }
  }

  public void paint(Graphics g) {}

  public void update(Graphics g) {
    //animate_tiles();

    if(buffer != null) {
      int tile_id;
      for(int y=0;y<MAP_ROWS;y++) {
        for(int x=0;x<MAP_COLS;x++) {
          tile_id = map[y][x]; 
          bufferg.drawImage(tile[tile_id], x * TILE_SIZE, y * TILE_SIZE, this);
        }
      }
    } 

    paint(bufferg);
    g.drawImage(buffer, screenX, screenY, this); 
    repaint(); 
  }

  public void keyReleased( KeyEvent e ) { }
  public void keyPressed( KeyEvent e ) { }
  public void keyTyped( KeyEvent e ) {  
    char c = e.getKeyChar();
    if(c == 'z') { screenX+=5; }
    else if(c == 'c') { screenX-=5; }
  }  
}