performance improvements

src/lib/GameEngine.js

@@ -214,18 +214,22 @@ class GameEngine extends EventManager{
 
         if (opts.ar) {
             renderer.xr.enabled = true;
-            document.body.appendChild(ARButton.createButton(renderer, {}));
+            this.arBtn = ARButton.createButton(renderer, {});
+            this.arBtn.classList.add('engine-ar-btn');
+            document.body.appendChild(this.arBtn);
         }
         if (opts.xr) {
             renderer.xr.enabled = true;
-            document.body.appendChild(XRButton.createButton(renderer, opts.depthSense ? {
+            this.xrBtn = XRButton.createButton(renderer, opts.depthSense ? {
                 'requiredFeatures': ['depth-sensing'],
                 'depthSensing': {
                     usagePreference: ["gpu-optimized"],
                     dataFormatPreference: ["unsigned-short"],
                     matchDepthView: false
                 }
-            } : {}));
+            } : {})
+            this.xrBtn.classList.add('engine-xr-btn');
+            document.body.appendChild(this.xrBtn);
             this.initXrControllers();
         }
 
@@ -611,6 +615,13 @@ class GameEngine extends EventManager{
         })
     }
 
+    destroy(){
+        this.renderer.dispose();
+        this.arBtn?.remove();
+        this.xrBtn?.remove();
+        this.stats?.dom?.remove();
+    }
+
     static textureLoader = new THREE.TextureLoader();
     static audioLoader = new THREE.AudioLoader();