J2ME开发RPG,ACT游戏的地图缓存类，卡马克卷轴算法封装类

package xtool; import java.io.IOException; import javax.microedition.lcdui.Graphics; import javax.microedition.lcdui.Image; /** * RPG ACT 等地图场景 缓存类 * @author 高雷 by 20090616 */ public class MapBuffer { private final int screen_w; //屏幕的宽度 private final int screen_h; //屏幕的高度 private final int tile_w; //地图瓦片的宽 private final int tile_h; //地图瓦片的高 private final int screen_tile_columns; //屏幕上瓦片的列数(一行上的TILE个数) private final int screen_tile_rows; //屏幕上瓦片的行数(一列上的TILE个数) private final int buffer_tile_columns; //缓冲区瓦片的列数(一行上的TILE个数) private final int buffer_tile_rows; //缓冲区瓦片的行数(一列上的TILE个数) private final int buffer_image_width; //缓冲区图片的宽度 private final int buffer_image_height; //缓冲区图片的高度 private final int map_width_pix; //地图大小pix需要给出 private final int map_height_pix; //地图大小pix需要给出 private final int map_width_tile; //地图大小TILE数量需要给出 private final int map_height_tile; //地图大小TILE数量需要给出 private final int s_t_x = 0; //保留该参数不知道干啥的screen_trans_x private final int s_t_y = 0; //保留该参数不知道干啥的screen_trans_y private int tile_x; //瓦片的屏幕坐标x private int tile_y; //瓦片的屏幕坐标x private int screen_x = 0; //屏幕左上角 在地图上的左边 偏移（需要给出因为地图初始位置不一定在哪） private int screen_y = 0; //屏幕左上角 在地图上的左边 偏移 private byte[][] map_data; //地图数据//需要外包传入 private Image map_img; //地图数据//需要外包传入 private Image buffer_img = null; //缓存区图片 private Graphics buffer_g = null; //缓存区绘制设备 private boolean first = true; public MapBuffer() { this( 240, 320, 32, 32, 300, 500,0,0 ); } /** * 构造方法 * @param screen_width * @param screen_height * @param _tile_w * @param _tile_h */ public MapBuffer( int screen_width, int screen_height, int _tile_w, int _tile_h, int _map_width, int _map_height,int _screen_x, int _screen_y ) { if( screen_width < 1 || screen_height < 1 || _tile_w < 1 || _tile_h < 1 || _map_width<screen_width || _map_height<screen_height ) throw new IllegalArgumentException(); screen_w = screen_width; screen_h = screen_height; tile_w = _tile_w; tile_h = _tile_h; map_width_pix = _map_width; map_height_pix = _map_height; map_width_tile = getInt4Float(_map_width, _tile_w); map_height_tile = getInt4Float(_map_height,_tile_h); setMapOff( _screen_x, _screen_y ); //屏幕上瓦片的列数(一行上的TILE个数) screen_tile_columns = getInt4Float( screen_w, tile_w ); //屏幕上瓦片的行数(一列上的TILE个数) screen_tile_rows = getInt4Float( screen_h, tile_h ); //缓冲区瓦片的列数(一行上的TILE个数) buffer_tile_columns = screen_tile_columns+1; //缓冲区瓦片的行数(一列上的TILE个数) buffer_tile_rows = screen_tile_rows+1; buffer_image_width = buffer_tile_columns * tile_w; // 缓冲区图片的宽度 buffer_image_height= buffer_tile_rows * tile_h; // 缓冲区图片的高度 buffer_img = Image.createImage(buffer_image_width,buffer_image_height); buffer_g = buffer_img.getGraphics(); first = true; } /** * 得到一个有小数就进位的整数，如(5、3)就是 5/3 返回2 * @param numerator 分子 * @param denominator 分母 * @return 如果有小数 就要进1 */ private int getInt4Float(int numerator, int denominator) { if( numerator < 1 || denominator < 1 ) throw new IllegalArgumentException(); return numerator/denominator+(numerator%denominator==0?0:1);//防止小数 } /** * 设置地图的数据和图片 */ public void setMap(byte[][] mapData, Image mapImg) { map_data = mapData; //地图数据//需要外包传入 map_img = mapImg; //地图图片//需要外包传入 } /** * 设置屏幕在地图上的偏移位置 * @param _screen_x * @param _screen_y */ private void setMapOff(int _screen_x,int _screen_y) { screen_x = _screen_x; screen_y = _screen_y; checkScreenOff(); tile_x = screen_x/tile_w; tile_y = screen_y/tile_h; } /** * 卷动绘制对象，根据需要进行缓冲//用于测试 * @param dx x方向移动距离 * @param dy y方向移动距离 */ public void scroll( int dx, int dy ) { screen_x += dx; screen_y += dy; checkScreenOff(); } /** * 检测屏幕是否完全在地图上 */ private void checkScreenOff() { if( screen_x < 0 ) { screen_x = 0; } else if( screen_x > map_width_pix - screen_w ) { screen_x = map_width_pix - screen_w; } if( screen_y < 0 ) { screen_y = 0; } else if( screen_y > map_height_pix - screen_h ) { screen_y = map_height_pix - screen_h; } } /** * 将此缓冲绘制到g * @param x 屏幕做上角位于地图上的坐标偏移 * @param y 屏幕做上角位于地图上的坐标偏移 */ public final void paint( Graphics g, int x, int y ) { screen_x = x; screen_y = y; checkScreenOff(); int now_tile_x = screen_x / tile_w; int now_tile_y = screen_y / tile_h; int start_x = now_tile_x; int start_y = now_tile_y; int end_x = start_x + screen_tile_columns; int end_y = start_y + screen_tile_rows; if( first ) { first = false; draw_buffer( buffer_g, start_x, start_y, end_x, end_y ); tile_x = now_tile_x; tile_y = now_tile_y; } if( now_tile_x != tile_x ) { int start_buffer_x; int end_buffer_x; if( now_tile_x > tile_x ) { start_buffer_x = tile_x + buffer_tile_columns; end_buffer_x = now_tile_x + screen_tile_columns; } else { start_buffer_x = now_tile_x; end_buffer_x = tile_x - 1; } draw_buffer( buffer_g, start_buffer_x, start_y, end_buffer_x, end_y ); tile_x = now_tile_x; } if( now_tile_y != tile_y ) { int start_buffer_y; int end_buffer_y; if( now_tile_y > tile_y ) { start_buffer_y = tile_y + buffer_tile_rows; end_buffer_y = now_tile_y + screen_tile_rows; } else { start_buffer_y = now_tile_y; end_buffer_y = tile_y - 1; } draw_buffer( buffer_g, start_x, start_buffer_y, end_x, end_buffer_y ); tile_y = now_tile_y; } int start_draw_x = ( screen_x ) % buffer_image_width; int end_draw_x = ( screen_x + screen_w ) % buffer_image_width; int start_draw_y = ( screen_y ) % buffer_image_height; int end_draw_y = ( screen_y + screen_h ) % buffer_image_height; if( end_draw_x > start_draw_x ) { if( end_draw_y > start_draw_y ) { draw_part_buffer( g, start_draw_x, start_draw_y, screen_w, screen_h, s_t_x, s_t_y ); } else { draw_part_buffer( g, start_draw_x, start_draw_y, screen_w, screen_h - end_draw_y, s_t_x, s_t_y ); draw_part_buffer( g, start_draw_x, 0, screen_w, end_draw_y, s_t_x, s_t_y + screen_h - end_draw_y ); } } else if( end_draw_y > start_draw_y ) { draw_part_buffer( g, start_draw_x, start_draw_y, screen_w - end_draw_x, screen_h, s_t_x, s_t_y ); draw_part_buffer( g, 0, start_draw_y, end_draw_x, screen_h, s_t_x + screen_w - end_draw_x, s_t_y ); } else { draw_part_buffer( g, start_draw_x, start_draw_y, screen_w - end_draw_x, screen_h - end_draw_y, s_t_x, s_t_y ); draw_part_buffer( g, start_draw_x, 0, screen_w - end_draw_x, end_draw_y, s_t_x, s_t_y + screen_h - end_draw_y ); draw_part_buffer( g, 0, start_draw_y, end_draw_x, screen_h - end_draw_y, s_t_x + screen_w - end_draw_x, s_t_y ); draw_part_buffer( g, 0, 0, end_draw_x, end_draw_y, s_t_x + screen_w - end_draw_x, s_t_y + screen_h - end_draw_y ); } } /** * 绘制 缓存区的一部分 */ private void draw_part_buffer( Graphics g, int srcX, int srcY, int width, int height, int desX, int desY ) { g.setClip( desX, desY, width, height ); g.drawImage( buffer_img, desX - srcX, desY - srcY, Graphics.LEFT|Graphics.TOP ); } /** * 绘制 缓存区 */ private void draw_buffer( Graphics g, int start_x, int