gridnode.java

一个基于J2ME的pacman游戏

/**
 * PacMan for J2ME Devices
 * CS 327 - Design Project, Fall 2002
 * University of Illinois, Urbana-Champaign
 * 
 * file: GridNode.java 
 * contact: Braden Kowitz
 * date: 11/24/02
 **/

//----------------------------------------------------------------------------//

import javax.microedition.lcdui.*;

/**
 * Represents a cell on the gameboard.
 * Nodes can draw itself and also contain informaion on the node's contents
 **/
public class GridNode
{

	//--------------------------//
	// ENUM
	//--------------------------//
	
	//@{
	
	/**
	 * Enum value for the pellet_ member.
	 **/
	public static final int NO_PELLET = 0;
	/**
	* Enum value for the pellet_ member.
	* Small pellets are worth points.
	**/
	public static final int SMALL_PELLET = 1;
	/**
	* Enum value for the pellet_ member.
	* Large pellets make pacman eat ghosts for a set ammount of time.
	**/
	public static final int BIG_PELLET = 2;

	//@}
	
	//--------------------------//
	// GRID SIZE
	//--------------------------//
	
	/**
	 * Defines the size of the grid squares.
	 * Units are pixels.
	 **/
	private static int size_;

	/**
	 * @param i size in pixels for all GridNode objects
	 **/
	public static void setSize(int i)
	{
		size_ = i;
	}

	/**
	 * @return The size in pixels for all GridNode objects
	 **/
	public static int getSize()
	{
		return size_;
	}

	//--------------------------//
	// MEMBER VARIABLES
	//--------------------------//
	
	/**
	 * Defines the type of pellet that is in the GridNode.
	 * Valid values are
	 * - NO_PELLET
	 * - SMALL_PELLET
	 * - BIG_PELLET
	 **/
	private int pellet_;

	//@{
	
	/**
	 * Pointer to the GridNode to the left of this one on the game board.
	 * This value is null when there is no path for actors to move
	 * to the left.
	 **/
	private GridNode left_;
	
	/**
	 * Pointer to the GridNode to the right of this one on the game board.
	 * This value is null when there is no path for actors to move
	 * to the right.
	 **/
	private GridNode right_;
	
	/**
	 * Pointer to the GridNode up from this one on the game board.
	 * This value is null when there is no path for actors to move up.
	 **/
	private GridNode up_;
	
	/**
	 * Pointer to the GridNode down from this one on the game board.
	 * This value is null when there is no path for actors to move down.
	 **/
	private GridNode down_;

	//@}
	
	/**
	 * Position of this GridNode in the X axis.
	 * - These are grid co-ordinates, not pixels.
	 * - This is specified during object construction.
	 **/
	private int posX_;
	
	/**
	 * Position of this GridNode in the Y axis.
	 * - These are grid co-ordinates, not pixels.
	 * - This is specified during object construction.
	 **/
	private int posY_;

	//@{
	
	/**
	 * X pixel coord of the Upper Left corner of this GridNode
	 **/
	private int pixelULX_;
	
	/**
	 * Y pixel coord of the Upper Left corner of this GridNode
	 **/
	private int pixelULY_;

	/**
	 * X pixel coord of the Lower Right corner of this GridNode
	 **/
	private int pixelLRX_;
	
	/**
	 * Y pixel coord of the Lower Right corner of this GridNode
	 **/
	private int pixelLRY_;
	
	/**
	 * X pixel coord of the Center of this GridNode
	 **/
	private int pixelCX_;
	
	/**
	 * Y pixel coord of the Center of this GridNode
	 **/
	private int pixelCY_;

	//@}
	
	//--------------------------//
	// PUBLIC FUNCTIONS
	//--------------------------//
  
	/**
	 * Constructor for a GridNode
	 * - These are grid co-ordinates, not pixels.
	 * @param x Position of this GridNode in the X axis.
	 * @param y Position of this GridNode in the Y axis.
	 **/
	public GridNode(int x, int y)
	{
		posX_ = x;
		posY_ = y;

		left_ = null;
		right_ = null;
		up_ = null;
		down_ = null;

		pellet_ = SMALL_PELLET;	

		//set the pixel positions:
		// upper left
		pixelULX_ = posX_ * size_;
		pixelULY_ = posY_ * size_;
		// lower right
		pixelLRX_ = pixelULX_ + size_ -1;
		pixelLRY_ = pixelULY_ + size_ -1;
		// center
		pixelCX_ = (pixelULX_ + pixelLRX_)/2;
		pixelCY_ = (pixelULY_ + pixelLRY_)/2;
	}

	
	/**
	 * @return the X pixel coord of the Center of this GridNode
	 **/
	public int pixelCenterX()
	{
		return pixelCX_;
	}
	
	/**
	 * @return the X pixel coord of the Center of this GridNode
	 **/
	public int pixelCenterY()
	{
		return pixelCY_;
	}
	
	//@{
	
	/**
	 * Sets the pointer to the GridNode to the left of this one on the game board.
	 * This value is null when there is no path for actors to move
	 * to the left.
	 * 
	 * @param n GridNode object or null
	 **/
	public void setLeft(GridNode  n)
	{ 
		left_ = n;
	}

	/**
	 * Sets the pointer to the GridNode to the right of this one on the game board.
	 * This value is null when there is no path for actors to move
	 * to the right.
	 * 
	 * @param n GridNode object or null
	 **/
	public void setRight(GridNode n) 
	{
		right_ = n; 
	}
	
	/**
	 * Sets the pointer to the GridNode up from this one on the game board.
	 * This value is null when there is no path for actors to move up.
	 * 
	 * @param n GridNode object or null
	 **/
	public void setUp(GridNode  n)
	{ 
		up_ = n;
	}
	
	/**
	 * Sets the pointer to the GridNode down from this one on the game board.
	 * This value is null when there is no path for actors to move down.
	 * 
	 * @param n GridNode object or null
	 **/
	public void setDown(GridNode  n) { down_ = n; }
	
	/**
	 * Gets the pointer to the GridNode left from this one on the game board.
	 * This value is null when there is no path for actors to move left.
	 * 
	 * @return GridNode object or null
	 **/
	public GridNode getLeft()  { return left_; }
	
	/**
	 * Gets the pointer to the GridNode right from this one on the game board.
	 * This value is null when there is no path for actors to move right.
	 * 
	 * @return GridNode object or null
	 **/
	public GridNode getRight() { return right_; }
	
	/**
	 * Gets the pointer to the GridNode up from this one on the game board.
	 * This value is null when there is no path for actors to move up.
	 * 
	 * @return GridNode object or null
	 **/
	public GridNode getUp()    { return up_; }

	/**
	 * Gets the pointer to the GridNode down from this one on the game board.
	 * This value is null when there is no path for actors to move down.
	 * 
	 * @return GridNode object or null
	 **/
	public GridNode getDown()  { return down_; }

	//@}
	
	/**
	 * Sets the type of pellet that is in this GridNode.
	 * - Valid values are
	 *   - NO_PELLET
	 *   - SMALL_PELLET
	 *   - BIG_PELLET
	 * @param i *_PELLET enum.
	 */
	public void setPellet(int i)
	{
		pellet_ = i;
	}
	
	/**
	 * Returns the type of pellet that is in this GridNode.
	 * - Valid values are
	 *   - NO_PELLET
	 *   - SMALL_PELLET
	 *   - BIG_PELLET
	 * @return *_PELLET enum.
	 */
	public int getPellet()
	{
		return pellet_;
	}

	/**
	 * This function is responsible for painting the GridNode
	 * @param g Graphics object where drawing should take place.
	 **/
	public void paint(Graphics g)
	{
		// clear the square
		g.setColor(255,255,255);
		g.fillRect(pixelULX_,pixelULY_,pixelLRX_,pixelLRY_);

		// draw the borders:
		g.setColor(0,0,0);
		if (left_  == null) g.drawLine(pixelULX_,pixelULY_,pixelULX_,pixelLRY_);
		if (right_ == null) g.drawLine(pixelLRX_,pixelULY_,pixelLRX_,pixelLRY_);
		if (up_    == null) g.drawLine(pixelULX_,pixelULY_,pixelLRX_,pixelULY_);
		if (down_  == null) g.drawLine(pixelULX_,pixelLRY_,pixelLRX_,pixelLRY_);

		// draw the dots:

		int radius = 0;
		if (pellet_ == BIG_PELLET)
			radius = size_ / 3;
		if (pellet_ == SMALL_PELLET)
			radius = size_ / 5;
		if (pellet_ != NO_PELLET)
			g.fillArc(pixelCX_,pixelCY_,radius,radius,0,360);

	}
	
}
//----------------------------------------------------------------------------//