From 0dfdb23bfb0a97957de61babb3fd5e69b7660b30 Mon Sep 17 00:00:00 2001
From: Jonathan Calvert <38069151+JDCalvert@users.noreply.github.com>
Date: Mon, 28 Feb 2022 20:17:54 +0000
Subject: [PATCH] Levels Compatibility: Clear pathfinding cache after changing
 elevation (#173)

---
 js/pathfinding.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/js/pathfinding.js b/js/pathfinding.js
index 7e89dad..1f663b9 100644
--- a/js/pathfinding.js
+++ b/js/pathfinding.js
@@ -7,6 +7,7 @@ import {getSnapPointForTokenObj, iterPairs} from "./util.js";
 import * as GridlessPathfinding from "../wasm/gridless_pathfinding.js"
 
 let cachedNodes = undefined;
+let cacheElevation;
 let use5105 = false;
 let gridlessPathfinders = new Map();
 let gridWidth, gridHeight;
@@ -22,6 +23,8 @@ export function isPathfindingEnabled() {
 }
 
 export function findPath(from, to, token, previousWaypoints) {
+	checkCacheValid(token);
+	
 	if (canvas.grid.type === CONST.GRID_TYPES.GRIDLESS) {
 		let tokenSize = Math.max(token.data.width, token.data.height) * canvas.dimensions.size;
 		let pathfinder = gridlessPathfinders.get(tokenSize);
@@ -161,6 +164,20 @@ export function wipePathfindingCache() {
 		debugGraphics.removeChildren().forEach(c => c.destroy());
 }
 
+/**
+ * Check if the current cache is still suitable for the path we're about to find. If not, clear the cache
+ */
+ function checkCacheValid(token) {
+	// If levels is enabled, the cache is invalid if it was made for a 
+	if (game.modules.get("levels")?.active) {
+		const tokenElevation = token.data.elevation;
+		if (tokenElevation !== cacheElevation) {
+			cacheElevation = tokenElevation;
+			wipePathfindingCache();
+		}
+	}
+}
+
 export function initializePathfinding() {
 	gridWidth = Math.ceil(canvas.dimensions.width / canvas.grid.w);
 	gridHeight = Math.ceil(canvas.dimensions.height / canvas.grid.h);