Update app.py

app.py

@@ -365,14 +365,20 @@ with gr.Blocks(css=css) as demo:
               this.parentNode.childNodes[2].innerText = BABYLON.Engine.LastCreatedScene.activeCamera.metadata.pipeline.imageProcessing.exposure;
             '/><span>1.0</span>""")
             canvas = gr.HTML(value="""<a href='#' onclick='
+              if (!BABYLON.Engine.LastCreatedScene.activeCamera.metadata) {
+                BABYLON.Engine.LastCreatedScene.activeCamera.metadata = { 
+                  screenshot: true,
+                  pipeline: new BABYLON.DefaultRenderingPipeline(\"default\", true, BABYLON.Engine.LastCreatedScene, [BABYLON.Engine.LastCreatedScene.activeCamera]) 
+                }
+              } 
               var cntxt = document.getElementsByClassName(\"model3D\")[0].getElementsByTagName(\"canvas\")[0].getContext(\"webgl2\");
               this.innerText = cntxt;
-              window.screenshot = true;
 
 BABYLON.Engine.LastCreatedScene.getEngine().onEndFrameObservable.add(function () {
   alert(\"begin\");
-  if (window.screenshot === true) {
-    window.screenshot = false;
+  if (BABYLON.Engine.LastCreatedScene.activeCamera.metadata.screenshot === true) {
+    BABYLON.Engine.LastCreatedScene.activeCamera.metadata.screenshot = false;
+    alert(\"do\");
     Tools.CreateScreenshotUsingRenderTarget(
       BABYLON.Engine.LastCreatedScene.getEngine(),
       BABYLON.Engine.LastCreatedScene.activeCamera,