created path finding web worker

2026-06-26 13:04:35 +00:00 · 2024-11-28 12:25:34 -08:00
parent 2216c34c41
commit 3e4f4e42cf
24 changed files with 643 additions and 306 deletions
@@ -0,0 +1,98 @@
+import { Tile } from "../game/Game";
+import { manhattanDist } from "../Util";
+import { AStar } from "./AStar";
+
+export enum PathFindResultType {
+    NextTile,
+    Pending,
+    Completed,
+    PathNotFound
+}
+
+export type TileResult = {
+    type: PathFindResultType.NextTile;
+    tile: Tile
+} | {
+    type: PathFindResultType.Pending;
+} | {
+    type: PathFindResultType.Completed;
+    tile: Tile
+} | {
+    type: PathFindResultType.PathNotFound;
+}
+
+
+export class PathFinder {
+
+    private curr: Tile = null
+    private dst: Tile = null
+    private path: Tile[]
+    private aStar: AStar
+    private computeFinished = true
+
+    constructor(
+        private iterations: number,
+        private canMove: (t: Tile) => boolean,
+        private maxTries: number = 20
+    ) { }
+
+    nextTile(curr: Tile, dst: Tile, dist: number = 1): TileResult {
+        if (curr == null) {
+            console.error('curr is null')
+        }
+        if (dst == null) {
+            console.error('dst is null')
+        }
+
+        if (manhattanDist(curr.cell(), dst.cell()) < dist) {
+            return { type: PathFindResultType.Completed, tile: curr }
+        }
+
+        if (this.computeFinished) {
+            if (this.shouldRecompute(curr, dst)) {
+                this.curr = curr
+                this.dst = dst
+                this.path = null
+                this.aStar = new AStar(curr, dst, this.canMove, sn => ((sn as Tile).neighbors()), this.iterations, this.maxTries)
+                this.computeFinished = false
+                return this.nextTile(curr, dst)
+            } else {
+                return { type: PathFindResultType.NextTile, tile: this.path.shift() }
+            }
+        }
+
+        switch (this.aStar.compute()) {
+            case PathFindResultType.Completed:
+                this.computeFinished = true
+                this.path = this.aStar.reconstructPath().map(sn => sn as Tile)
+                // Remove the start tile
+                this.path.shift()
+                return this.nextTile(curr, dst)
+            case PathFindResultType.Pending:
+                return { type: PathFindResultType.Pending }
+            case PathFindResultType.PathNotFound:
+                return { type: PathFindResultType.PathNotFound }
+        }
+    }
+
+    private shouldRecompute(curr: Tile, dst: Tile) {
+        if (this.path == null || this.curr == null || this.dst == null) {
+            return true
+        }
+        const dist = manhattanDist(curr.cell(), dst.cell())
+        let tolerance = 10
+        if (dist > 50) {
+            tolerance = 10
+        } else if (dist > 25) {
+            tolerance = 5
+        } else if (dist > 10) {
+            tolerance = 3
+        } else {
+            tolerance = 0
+        }
+        if (manhattanDist(this.dst.cell(), dst.cell()) > tolerance) {
+            return true
+        }
+        return false
+    }
+}