IsoUtils.java

package com.snowcattle.game.common.util;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.image.BufferedImage;

public class IsoUtils {
	// masks的区域
	// _______
	// |  /\  |
	// | / 	\ |
	// |/ 	 \|
	// |\ 	 /|
	// | \ 	/ |
	// |__\/__|
	public static final byte AREA_CENTER = 0;
	public static final byte AREA_NORTHEAST = 1;
	public static final byte AREA_SOUTHEAST = 2;
	public static final byte AREA_NORTHWEST = 3;
	public static final byte AREA_SOUTHWEST = 4;

	public static final int TILE_WIDTH = 64;
	public static final int TILE_HEIGHT = 32;
	public static final int HALF_TILE_WIDTH = 32;
	public static final int HALF_TILE_HEIGHT = 16;

	private static byte[][] masks;

	static {
		initMask();
	}

	public static void initMask() {
		int width = TILE_WIDTH;
		int height = TILE_HEIGHT;

		Polygon poly = new Polygon();
		poly.addPoint(width / 2, 0);
		poly.addPoint(width, height / 2);
		poly.addPoint(width / 2, height);
		poly.addPoint(0, height / 2);

		BufferedImage bufimage = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
		Graphics2D g2d = bufimage.createGraphics();
		g2d.setColor(Color.WHITE);
		g2d.fillRect(0, 0, width, height);

		g2d.setColor(Color.BLACK);
		g2d.fillPolygon(poly);

		masks = new byte[height][width];
		int w2 = width / 2;
		int h2 = height / 2;
		for (int row = 0; row < height; row++) {
			for (int col = 0; col < width; col++) {
				int rgb = bufimage.getRGB(col, row);
				if (rgb == 0xFF000000) {
					masks[row][col] = AREA_CENTER;
				} else if (row < h2) {
					if (col < w2) {
						masks[row][col] = AREA_NORTHWEST;
					} else {
						masks[row][col] = AREA_NORTHEAST;
					}
				} else {
					if (col < w2) {
						masks[row][col] = AREA_SOUTHWEST;
					} else {
						masks[row][col] = AREA_SOUTHEAST;
					}
				}
			}
		}

		g2d.dispose();
		bufimage = null;
	}

	/**
	 * 返回tile坐标对应的网格的中点坐标
	 *
	 * @param x
	 *            tile所在列坐标
	 * @param y
	 *            tile所在行坐标
	 * @return
	 */
	public static Point tile2ImageCoord(int x, int y) {
		Point rt;
		if (y % 2 == 0) {
			rt = new Point(x * TILE_WIDTH, y * HALF_TILE_HEIGHT);
		} else {
			rt = new Point(x * TILE_WIDTH + HALF_TILE_WIDTH, y * HALF_TILE_HEIGHT);
		}
		return rt;

	}

	public static Point tile2ImageCoord(String str) {
		Point pt = null;
		try {
			if (str != null) {
				String[] coords = str.split(",");
				if (coords.length == 2) {
					pt = IsoUtils.tile2ImageCoord(Integer.parseInt(coords[0]), Integer.parseInt(coords[1]));
				}
			}
		} catch (NumberFormatException e) {
			e.printStackTrace();
			return null;
		}
		return pt;

	}

	public static Point image2TileCoord(int x, int y) {
		Point centerCellCoords = new Point(x / TILE_WIDTH, y / TILE_HEIGHT * 2 + 1);
		int offx = Math.abs(x % TILE_WIDTH);
		int offy = Math.abs(y % TILE_HEIGHT);
		switch (masks[offy][offx]) {
		case AREA_NORTHEAST: {
			centerCellCoords.x += 1;
			centerCellCoords.y--;
			break;
		}
		case AREA_NORTHWEST: {
			// centerCellCoords.x -=
			centerCellCoords.y--;
			break;
		}
		case AREA_SOUTHEAST: {
			centerCellCoords.x += 1;
			centerCellCoords.y++;
			break;
		}
		case AREA_SOUTHWEST: {
			// centerCellCoords.x
			centerCellCoords.y++;
			break;
		}
		}
		// System.out.println("[S2T]("+x+","+y+")<->("+centerCellCoords.x+","+centerCellCoords.y+")");
		if (x < 0) {
			centerCellCoords.x = -centerCellCoords.x;
		}
		if (y < 0) {
			centerCellCoords.y = -centerCellCoords.y;
		}
		return centerCellCoords;

	}

	public static void main(String[] args) {
		System.out.println(tile2ImageCoord(6, 32));
		System.out.println(image2TileCoord(1444 , 400));
	}

}