新增a*寻路

source/src/AI/Pathfinding/AStar/AstarGridGraph.ts

@@ -0,0 +1,67 @@
+/**
+ * 基本静态网格图与A*一起使用
+ * 将walls添加到walls HashSet，并将加权节点添加到weightedNodes
+ */
+class AstarGridGraph implements IAstarGraph<Point> {
+    public dirs: Point[] = [
+        new Point(1, 0),
+        new Point(0, -1),
+        new Point(-1, 0),
+        new Point(0, 1)
+    ];
+
+    public walls: Point[] = [];
+    public weightedNodes: Point[] = [];
+    public defaultWeight: number = 1;
+    public weightedNodeWeight = 5;
+
+    private _width;
+    private _height;
+    private _neighbors: Point[] = new Array(4);
+
+    constructor(width: number, height: number){
+        this._width = width;
+        this._height = height;
+    }
+
+    /**
+     * 确保节点在网格图的边界内
+     * @param node 
+     */
+    public isNodeInBounds(node: Point): boolean {
+        return 0 <= node.x && node.x < this._width && 0 <= node.y && node.y < this._height;
+    }
+
+    /**
+     * 检查节点是否可以通过。墙壁是不可逾越的。
+     * @param node 
+     */
+    public isNodePassable(node: Point): boolean {
+        return !this.walls.contains(node);
+    }
+
+    public search(start: Point, goal: Point){
+        return AStarPathfinder.search(this, start, goal);
+    }
+
+    public getNeighbors(node: Point): Point[] {
+        this._neighbors.length = 0;
+
+        this.dirs.forEach(dir => {
+            let next = new Point(node.x + dir.x, node.y + dir.y);
+            if (this.isNodeInBounds(next) && this.isNodePassable(next))
+                this._neighbors.push(next);
+        });
+
+        return this._neighbors;
+    }
+
+    public cost(from: Point, to: Point): number {
+        return this.weightedNodes.find((p)=> JSON.stringify(p) == JSON.stringify(to)) ? this.weightedNodeWeight : this.defaultWeight;
+    }
+
+    public heuristic(node: Point, goal: Point) {
+        return Math.abs(node.x - goal.x) + Math.abs(node.y - goal.y);
+    }
+
+}