mergeRPG_client/assets/script/manager/AStarHelper.ts

/*
 * @Author: gyw
 * @Date: 2019-09-09 
 * @Desc: A*寻路
 * tilemap专用
 */


export class AStarHelper {
    //其中的MAP.arr是二维数组
    public static searchRoad(map: cc.TiledLayer, start_x: number, start_y: number, end_x: number, end_y: number, colliderTiles?: any[]) {
        if (start_x == end_x && start_y == end_y) return null;
        let layerSize = map.getLayerSize();
        let rows = layerSize.width;    //行
        let cols = layerSize.height;    //列
        // let rows = PathMgr.getInstance().mapJson.length;    //行
        // let cols = PathMgr.getInstance().mapJson[0].length;    //列
        var openList = [],    //开启列表
            closeList = [],   //关闭列表
            result = [],      //结果数组
            result_index;   //结果数组在开启列表中的序号

        openList.push({ x: start_x, y: start_y, G: 0 });//把当前点加入到开启列表中，并且G是0

        do {
            var currentPoint = openList.pop();
            closeList.push(currentPoint);
            // if (Math.abs(currentPoint.x - start_x) > 10 || Math.abs(currentPoint.y - start_y) > 10) continue;

            var surroundPoint = this.SurroundPoint(currentPoint);
            for (var i in surroundPoint) {
                var item = surroundPoint[i];                //获得周围的八个点
                if (
                    item.x >= 0 &&                            //判断是否在地图上
                    item.y >= 0 &&
                    item.x < rows &&
                    item.y < cols &&
                    (this.checkCell(map, item.x, item.y) == 0 || this.checkCell(map, item.x, item.y) == 65) &&         //判断是否是障碍物 0代表是空位
                    this.existList(item, closeList) == -100         //判断是否在关闭列表中
                    && (!colliderTiles || !colliderTiles[item.x] || !colliderTiles[item.x][item.y])
                ) {
                    //g 到父节点的位置
                    //如果是上下左右位置的则g等于10，斜对角的就是14
                    var g = currentPoint.G + ((currentPoint.x - item.x) * (currentPoint.y - item.y) == 0 ? 10 : 14);
                    if (this.existList(item, openList) == -100) {       //如果不在开启列表中
                        //计算H，通过水平和垂直距离进行确定
                        item['H'] = Math.abs(end_x - item.x) * 10 + Math.abs(end_y - item.y) * 10;
                        item['G'] = g;
                        item['F'] = item['H'] + item['G'];
                        item['parent'] = currentPoint;
                        openList.push(item);
                    }
                    else {                                  //存在在开启列表中，比较目前的g值和之前的g的大小
                        var index = this.existList(item, openList);
                        //如果当前点的g更小
                        if (g < openList[index].G) {
                            openList[index].parent = currentPoint;
                            openList[index].G = g;
                            openList[index].F = g + openList[index].H;
                        }

                    }
                }
            }
            //如果开启列表空了，没有通路，结果为空
            if (openList.length == 0) {
                break;
            }
            openList.sort(this.sortF);//这一步是为了循环回去的时候，找出 F 值最小的, 将它从 "开启列表" 中移掉
        } while ((result_index = this.existList({ x: end_x, y: end_y }, openList)) == -100);

        //判断结果列表是否为空
        if (result_index == -100 || result_index == void 0) {
            result = [];
        }
        else {
            var currentObj = openList[result_index];
            do {
                //把路劲节点添加到result当中
                result.unshift({
                    x: currentObj.x,
                    y: currentObj.y
                });
                currentObj = currentObj.parent;
            } while (currentObj.x != start_x || currentObj.y != start_y);

        }
        return result;

    }
    //用F值对数组排序
    private static sortF(a, b) {
        return b.F - a.F;
    }
    //获取周围八个点的值
    public static SurroundPoint(curPoint) {
        var x = curPoint.x, y = curPoint.y;
        return [
            { x: x - 1, y: y - 1 },
            { x: x, y: y - 1 },
            { x: x + 1, y: y - 1 },
            { x: x + 1, y: y },
            { x: x + 1, y: y + 1 },
            { x: x, y: y + 1 },
            { x: x - 1, y: y + 1 },
            { x: x - 1, y: y }
        ]
    }
    //判断点是否存在在列表中，是的话返回的是序列号
    private static existList(point, list) {
        for (var i in list) {
            if (point.x == list[i].x && point.y == list[i].y) {
                return i;
            }
        }
        return -100;
    }

    //检测单元格是否是障碍物
    public static checkCell(mapLayer: cc.TiledLayer, x: number, y: number) {
        let res = mapLayer.getTileGIDAt(x, y);
        // let res  =  PathMgr.getInstance().mapJson[x][y];
        return res;
    }




}