wormfood.java

j2me中几个 很有代表性的小游戏,

/*
 *
 * Copyright © 2007 Sun Microsystems, Inc. All rights reserved.
 * Use is subject to license terms.
 */
/*
 * WormFood.java
 *
 * Created on March 30, 2001, 16:15
 * @version
 */
package example.wormgame;

import javax.microedition.lcdui.Graphics;


/**
 * WormFood is a food item that the worm can eat. It is placed at
 * a pseudo randomly generated location in the pit.
 */
public class WormFood {
    /** Current food location x coordinate in cells. */
    private int cellX;

    /** Current food location y coordinate in cells. */
    private int cellY;

    /*
     * These members are for convenience only. They are generated using
     * expensive multiplication operations and are cached for quick access
     */

    /** Current food location x coordinate in pixels. */
    private int x;

    /** Current food location y coordinate in pixels. */
    private int y;

    /** Size of arena in cells. */
    private long arenaSize;

    /**
     * Constructor for worm food object.
     * @param pit pit to which the food is associated. (unused currently)
     */
    public WormFood(WormPit pit) {
        arenaSize = WormPit.CellWidth * WormPit.CellHeight;
        regenerate();
    }

    /**
     * Returns true if the food item is at the given cell.
     * @param cx x coordinate of cell to test
     * @param cy y coordinate of cell to test
     * @return true, if the food is at the cell coordinate
     */
    public boolean isAt(int cx, int cy) {
        return ((this.cellX == cx) && (this.cellY == cy));
    }

    /**
     * Get the X coordinate of the cell that contains the food item.
     * @return x coordinate of food cell location
     */
    public int getX() {
        return cellX;
    }

    /**
     * Get the Y coordinate of the cell that contains the food item.
     * @return y coordinate of food cell location
     */
    public int getY() {
        return cellY;
    }

    /**
     * Regenerate the food item. Whenever the worm eats a piece of
     * food, this method is called.
     */
    public void regenerate() {
        int loc = (int)(System.currentTimeMillis() % arenaSize);
        cellY = (int)(loc / WormPit.CellWidth);
        cellX = (int)(loc % WormPit.CellHeight);
        y = cellY * WormPit.CELL_SIZE; // Cache to save time during paint
        x = cellX * WormPit.CELL_SIZE; // Cache to save time during paint
                                       // If food was generated outside of the board, try a new location

        if (!WormPit.isInBounds(cellX, cellY)) {
            regenerate();
        }
    }

    /**
     * Paint the piece of food.
     * @param g graphics object to receive rendering of food object
     */
    public void paint(Graphics g) {
        g.setColor(WormPit.FOOD_COLOUR);
        g.fillRect(x + 1, y + 1, WormPit.CELL_SIZE - 2, WormPit.CELL_SIZE - 2);
        g.setColor(WormPit.DRAW_COLOUR);
        g.drawRect(x, y, WormPit.CELL_SIZE - 1, WormPit.CELL_SIZE - 1);
    }
}