From feb595cb555b5807cde0b83d4560983e57f8657b Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Tue, 10 Jan 2023 15:14:01 +0100
Subject: [PATCH] Repair gamepad input state tracking

---
 src/engine.ts | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/engine.ts b/src/engine.ts
index 50a35be..bfd7b8d 100644
--- a/src/engine.ts
+++ b/src/engine.ts
@@ -12,6 +12,8 @@ import {
     WebXRSessionManager,
 } from '@babylonjs/core/Legacy/legacy';
 
+import { log } from './log.js';
+
 if ((navigator as any).oscpu?.startsWith('Linux')) {
     // ^ oscpu is undefined on chrome on Android, at least...
 
@@ -91,7 +93,7 @@ export class RunningEngine {
     leanBase: { position: Vector3 } | null = null;
     recenterBase: { rotation: Quaternion } | null = null;
 
-    padStates: Map<Gamepad, GamepadState> = new Map();
+    padStates: Map<number, GamepadState> = new Map();
 
     static async start(
         interactivity: Interactivity,
@@ -154,20 +156,30 @@ export class RunningEngine {
         }
 
         this.engine.runRenderLoop(() => {
-            Array.from(navigator.getGamepads()).forEach(gp => {
-                if (gp !== null) this.checkGamepadInput(gp);
-            });
-            this.scene.render();
+            try {
+                Array.from(navigator.getGamepads()).forEach(gp => {
+                    if (gp !== null) this.checkGamepadInput(gp);
+                });
+                this.scene.render();
+            } catch (e) {
+                console.error('Error in render loop', e);
+                throw e;
+            }
         });
 
         window.addEventListener("resize", () => this.engine.resize());
     }
 
     padStateFor(gp: Gamepad): GamepadState {
-        const state = this.padStates.get(gp);
-        if (state) return state;
+        const state = this.padStates.get(gp.index);
+        if (state) {
+            // Apparently reusing Gamepad instances across frames doesn't work,
+            // so we update (!) the stored instance here:
+            state.gp = gp;
+            return state;
+        }
         const newState = new GamepadState(gp);
-        this.padStates.set(gp, newState);
+        this.padStates.set(gp.index, newState);
         return newState;
     }