map.java

J2ME斜45度游戏引擎

package isoj2me;

import java.io.*;

/**
 * <p>isoj2me: Character</p>
 * <p>This class manages Maps with load functions to read ascii map files.</p>
 * <p>Copyright: Copyright (c) 2004</p>
 * <p>License: Lesser GPL (http://www.gnu.org)</p>
 * <p>Company: <a href=http://www.mondonerd.com target="_blank">Mondonerd.com</a></p>
 * @author Massimo Maria Avvisati
 * @version alpha 0.4
 */

public class Map {
  public int[][] layers;
  private int height;
  private int width;
  public int numberOfLayers;
  public short basic_ch = 48; //This is the value used when creating empty layer

  /**
   * This method load the map files and put them into the layers array.<br>
   * The filenames of a layers should be like <b>baseFilenmae<i>0</i></b>, <b>baseFilenmae<i>1</i></b>, ..., <b>baseFilenmae<i>numberOfLayers</i></b>
   * @param baseFilename name for the map files
   * @param numberOfLayers number of layers to load
   */

  public Map(String baseFilename, int numberOfLayers) {
    int[] size = getFileShape(baseFilename + "0");
    this.width = size[0];
    this.height = size[1];
    this.numberOfLayers = numberOfLayers;
    layers = new int[numberOfLayers][width * height];

    for (int i = 0; i < numberOfLayers; i++) {
      load(baseFilename + i, i);
    }
  }

  /**
   * Return the value stored in the map array at given position
   * @param layer layer to seek (z)
   * @param x x
   * @param y y
   * @return value stored (tile)
   */

  public int getCell(int layer, int x, int y) {
    int tile = -1;
    if (layer < 0) {
      layer = 0;
    }
    if (layer >= numberOfLayers) {
      layer = numberOfLayers - 1;
    }
    if (layers[layer] != null) {
      if (y * width + x < height * width && y * width + x >= 0) {
	tile = layers[layer][y * width + x];
      }
    }
    return tile;
  }

  /**
   * Set the value of a cell in the layer specified
   * @param layer layer (z)
   * @param x x
   * @param y y
   * @param tile number that identify the tile
   * @throws java.lang.Exception
   */

  public void setCell(int layer, int x, int y, int tile) {
    if (layer < 0) {
      layer = 0;
    }
    if (layer > numberOfLayers) {
      layer = numberOfLayers - 1;
    }

    if (layers[layer] != null) {
      if (y * width + x <= height * width && y * width + x >= 0) {
	layers[layer][y * width + x] = tile;
      }
    }
  }

  /**
   * This load a layer reading it from an ascii file and store it into the layers array
   * @param filename file to load
   * @param layer layer index where to store it
   */

  private void load(String filename, int layer) {
    int ch;
    int counter = 0;
    Class c = this.getClass();
    InputStream is = c.getResourceAsStream(filename);

    try {
      InputStreamReader isr = new InputStreamReader(is);

      while ( (ch = is.read()) > -1) { //It read all the map file
	if (ch != 10) { //If the char is not \n it store it in the map array
	  layers[layer][counter] = (short) ch; //The char is stored as a short value
	  counter++; //The next map index
	}
      }
    }
    catch (Exception ex) {
      System.out.println("Cannot read layer " + layer + ":" + ex);
      for (int i = 0; i < height * width; i++) {
	layers[layer][i] = basic_ch;
      }
    }

  }

  /**
   * Print a readeable map of all the layers
   * @return string to print
   */

  public String toString() {
    String result = "(";
    for (int i = 0; i < numberOfLayers; i++) {
      for (int j = 0; j < (width * height); j++) {
	if (j % width == 0) {
	  result = result + "\n";
	}
	result = result + layers[i][j] + " ";
      }
      result = result + "-----\n";

    }
    result = result + ")";

    return result;
  } // end toString

  /**
   * Simply return the map width
   * @return width
   */
  public int getWidth() {
    return width;
  }

  /**
   * Simply return the map height
   * @return height
   */

  public int getHeight() {
    return height;
  }

  /**
   * This is a method to see the "shape" of a map
   * @param filename file to analyze
   * @return an array of (width, height)
   */

  private int[] getFileShape(String filename) {
    int counter = 0;
    int counter2 = 0;
    int ch = 0;
    int[] size = new int[2];
    Class c = this.getClass();
    InputStream is = c.getResourceAsStream(filename);

    try {
      InputStreamReader isr = new InputStreamReader(is);

      while ( (ch = is.read()) > -1) { //It read all the map file
	if (ch != 10) {
	  counter++; //Increments the number of chars
	}
	else {
	  counter2++; //Increments the number of lines
	}
      }

    }
    catch (Exception ex) {
    }
    counter2++; //The last line has no break line...
    size[0] = counter / counter2; //This is the "width" of the map
    size[1] = counter2; //This is the "height" of the map
    return size;
  }

  /**
   * This method set null a layer. This layer will not be painted at all.
   * @param layerNumber The layer to clear
   */

  public void clearLayer(int layerNumber) {
    if (layerNumber > 0 && layerNumber < this.numberOfLayers) {
      for (int i = 0; i < height * width; i++) {
	layers[layerNumber][i] = basic_ch;
      }

    }
  }
}