修复physics register失效问题

source/src/Physics/Physics.ts

@@ -1,8 +1,14 @@
 class Physics {
     private static _spatialHash: SpatialHash;
+    /** 调用reset并创建一个新的SpatialHash时使用的单元格大小 */
+    public static spatialHashCellSize = 100;
 
     public static readonly allLayers: number = -1;
 
+    public static reset(){
+        this._spatialHash = new SpatialHash(this.spatialHashCellSize);
+    }
+
     public static overlapCircleAll(center: Vector2, randius: number, results: any[], layerMask = -1){
         return this._spatialHash.overlapCircle(center, randius, results, layerMask);
     }

source/src/Physics/Verlet/SpatialHash.ts

@@ -35,6 +35,21 @@ class SpatialHash {
         collider.registeredPhysicsBounds = bounds;
         let p1 = this.cellCoords(bounds.x, bounds.y);
         let p2 = this.cellCoords(bounds.right, bounds.bottom);
+
+        if (!this.gridBounds.contains(new Vector2(p1.x, p1.y))){
+            this.gridBounds = RectangleExt.union(this.gridBounds, p1);
+        }
+        
+        if (!this.gridBounds.contains(new Vector2(p2.x, p2.y))){
+            this.gridBounds = RectangleExt.union(this.gridBounds, p2);
+        }
+
+        for (let x = p1.x; x <= p2.x; x++){
+            for (let y = p1.y; y <= p2.y; y++){
+                let c = this.cellAtPosition(x, y, true);
+                c.push(collider);
+            }
+        }
     }
 
     public overlapCircle(circleCenter: Vector2, radius: number, results: Collider[], layerMask){