snake.java

classic 2D snake game

import java.util.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;


//class OptionsCanvas extends Canvas /*implements CommandListener  */{
//    Display disp;
//    GameCanvas game;
//    public int speed;  // 1000/(delay-10) or (delay = 1000/speed+10) max speed=100 == delay = 20, min speed=1 == delay = 1010 ms
//    //static final Command backCommand = new Command ("Back", Command.EXIT, 1);
//    
//    
//    OptionsCanvas (Display display, GameCanvas main) {
//        //this.addCommand (backCommand);
//        //this.setCommandListener(this);
//        speed=1000/(game.delay-10);
//        disp=display;
//        game=main;
//    }
//    
//    public void paint (Graphics g) {
//        g.setColor(0,0,255);
//        g.fillRect(0,0,game.sw,game.sh);
//        g.setColor(255,100,0);
//        g.drawString("Speed:", game.sw/2, game.sh/4, Graphics.TOP | Graphics.HCENTER);
//        
//        g.setColor(255,255,0);
//        g.fillRect(game.sw/4, game.sh/2, 3*(speed*game.sw)/100/4, game.sw/4);
//
//        g.setColor(100,255,0);
//        g.fillRect(game.sw/4, game.sh/2, game.sw*3/4, game.sw/4);        
//    }
//    
//    /* Handle the High Level Keys*/
//    public void commandAction (Command c, Displayable d) {
//      //if(c==backCommand) {
//      //  disp.setCurrent (game); 
//      //}
//    }       
//
//    /* Low level commands*/
//    public void keyPressed (int keyCode) {
//        switch(getGameAction(keyCode)) {
//            case RIGHT:
//                break;
//            case LEFT:                
//                break;
//        }
//        repaint ();
//    }
//    
//  
//}

class GameCanvas extends Canvas implements Runnable, CommandListener  {
/*  OptionsCanvas opt; */
  int delay=50;     //delay between two frames
  int speed=1000/(delay-10);
  long startTime;
  int seconds;
  Display display;
  Image offscreen;
  Random rnd;
  Snake midlet;
  int rd=255, gr=0, bl=0;
  public int sw, sh;
  int[] snake_x;
  int[] snake_y;
  int n_snake=8;      // current size of snake
  int snakewidth=6; // snake will be 6 pixels wide
  int growth_rate=3;
  int x_max, y_max;
  boolean first_run=false;
  int game_state=1;         // 1 - running
                            // 2 - menu (options)
  
  int apple_x, apple_y;
  
  char dir='u';
  int score=0;
 
    static final Command exitCommand = new Command ("Exit", Command.EXIT, 2);
    static final Command menuCommand = new Command ("Menu", Command.ITEM, 1);
  

   
    
  GameCanvas (Display display, Snake caller) {
    /*opt = new OptionsCanvas(display,this); */
    rnd = new Random();
    this.setFullScreenMode(true);
    midlet = caller;
    /* Set the high-level commands */
    this.addCommand (exitCommand);
    this.addCommand (menuCommand);
    this.setCommandListener(this);
    
    
    sw=getWidth();
    sh=getHeight();
    x_max=sw/snakewidth;
    y_max=sh/snakewidth;
    
    apple_x=Math.abs((rnd.nextInt())%x_max);
    apple_y=Math.abs((rnd.nextInt())%y_max);
    
    snake_x=new int[sw*sh/snakewidth/snakewidth];
    snake_y=new int[sw*sh/snakewidth/snakewidth];
    
    
    int i;
    for(i=0;i<n_snake;i++) {
        snake_x[i]=x_max/2;
        snake_y[i]=i;
    }
            
    this.display = display; // this -> the current class
    this.seconds = seconds;
 
    if (!isDoubleBuffered () && false)
      offscreen = Image.createImage (sw, sh);
 
    startTime = System.currentTimeMillis ();
  }
 
  public void paint (Graphics g) {
    
    // if offscreen is not present (auto double buffer), use orignal screen
    Graphics g2 = offscreen == null 
      ? g
      : offscreen.getGraphics ();
      
    // clear the screen
    g2.setColor (0, 0, 255);
    g2.fillRect (0, 0, sw, sh);
 
    
    //draw the apple
    g2.setColor(255,0,0);
    g2.fillArc(apple_x*snakewidth,apple_y*snakewidth,
                snakewidth, snakewidth, 0, 360);
    g2.setColor(255,100,10);
    g2.fillArc(apple_x*snakewidth+1,apple_y*snakewidth+2,
                2, 2, 0, 360);
    g2.setColor(50,255,10);
    g2.fillRect(apple_x*snakewidth+snakewidth/2,apple_y*snakewidth,
                1, 3);
    
    
    
    // draw the snake

    int i;
    for(i=0;i<n_snake;i++) {
        g2.setColor(200,180,20);
        g2.fillRect(snake_x[i]*snakewidth,snake_y[i]*snakewidth,
                snakewidth, snakewidth);
        g2.setColor(255,255,0);        
        g2.fillRect(snake_x[i]*snakewidth+1,snake_y[i]*snakewidth+1,
                snakewidth-1, snakewidth-1);
    }
    display.callSerially (this);
    

 
    // copy the buffer to the screen
    if (offscreen != null) 
      g.drawImage (offscreen, 0, 0, Graphics.TOP | Graphics.RIGHT); 
  }

    /* Handle the High Level Keys*/
    public void commandAction (Command c, Displayable d) {
      if(c==exitCommand) {
          midlet.destroyApp(false);
      }
      if(c==menuCommand) {
          speed=1000/(delay-10);
          game_state=2;
      }
    }       
  
    /* Low level commands*/
    public void keyPressed (int keyCode) {
        switch(keyCode) {
            case KEY_NUM2:
                if(dir!='d')dir='u';
                break;
            case KEY_NUM8:                
                if(dir!='u')dir='d';
                break;
            case KEY_NUM6:                                
                if(dir!='l')dir='r';
                break;
            case KEY_NUM4:
                if(dir!='r')dir='l';
                break;
        }
        switch(getGameAction(keyCode)) {
            case UP:
                if(dir!='d')dir='u';
                break;
            case DOWN:
                if(dir!='u')dir='d';
                break;
            case RIGHT:
                if(dir!='l')dir='r';
                break;
            case LEFT:                
                if(dir!='r')dir='l';
                break;
        }
        //repaint ();
    }

  
  public void run () {
    int i;
    i = (int) System.currentTimeMillis ();
    if(!first_run) {
        startTime=i;
        first_run=true;
    }

    if(Math.abs(i-startTime)>=delay) {
        startTime=startTime+delay; // = i;

        // shift the pieces forward
        for(i=n_snake-1;i>0;i--) {
            snake_x[i]=snake_x[i-1];
            snake_y[i]=snake_y[i-1];
        }

        // calculate the new piece (depending on the direction)
        switch(dir) {
            case 'd':
                snake_y[0]=snake_y[0]+1;
                if(snake_y[0]==y_max)snake_y[0]=0;
                break;

            case 'u':
                if(snake_y[0]==0)snake_y[0]=y_max-1;
                else snake_y[0]=snake_y[0]-1;
                break;

            case 'r':
                snake_x[0]=snake_x[0]+1;
                if(snake_x[0]==x_max)snake_x[0]=0;
                break;

            case 'l':
                if(snake_x[0]==0)snake_x[0]=x_max-1;
                else snake_x[0]=snake_x[0]-1;
                break;

        }

        /* Check if the snake is eating itself */
        for(i=1;i<n_snake;i++) {
            if(snake_x[i]==snake_x[0]&&snake_y[i]==snake_y[0]) {
                // GAME OVER
                Alert alert = new Alert ("Game Over");
                alert.setTimeout (Alert.FOREVER);
                alert.setString("Score: "+java.lang.String.valueOf(score));
                display.setCurrent (alert);
                
                n_snake=8;
                for(i=0;i<n_snake;i++) {
                    snake_x[i]=x_max/2;
                    snake_y[i]=i;
                }          
                dir='u';
                first_run=false;
                score=0;
            }
        }
        
        
        /* Check if an apple is eaten */
        if(snake_x[0]==apple_x&&snake_y[0]==apple_y) {
            for(i=n_snake;i<n_snake+growth_rate;i++) {
                snake_x[i]=snake_x[0];
                snake_y[i]=snake_y[0];
            }
                
            n_snake+=growth_rate;
            score+=9;
            apple_x=Math.abs((rnd.nextInt())%x_max);
            apple_y=Math.abs((rnd.nextInt())%y_max);
        }
        
        repaint();
    }   // the outermost if ends here
    else {
        display.callSerially (this);
    }
  } //function run ends here
}   // class GameCanvas ends here
 
 
public class Snake extends MIDlet {
    
  public static Display display;
  public void startApp () {
    display = Display.getDisplay (this);
    display.setCurrent (new GameCanvas (display, this)); 
  }
 
  public void pauseApp () {
  }
  
  public void destroyApp (boolean forced) {
    this.notifyDestroyed();
  }
}