                 session.addInput(audioInput)
                 session.addOutput(audioOutput)
             }
-            try addCamera(session:session)
-            if let _ = self.camera {
-                let videoOutput = AVCaptureVideoDataOutput()
-                videoOutput.videoSettings = [
-                  kCVPixelBufferPixelFormatTypeKey as AnyHashable: kCVPixelFormatType_32BGRA
-                ]
-                videoOutput.setSampleBufferDelegate(self, queue: .main)
-                session.addOutput(videoOutput)
+            guard try addCamera(session:session) else {
+                print("VSVS: no camera on this device")
+                return
+            }
+            let videoOutput = AVCaptureVideoDataOutput()
+            videoOutput.videoSettings = [
+              kCVPixelBufferPixelFormatTypeKey as AnyHashable: kCVPixelFormatType_32BGRA
+            ]
+            videoOutput.setSampleBufferDelegate(self, queue: .main)
+            session.addOutput(videoOutput)
 
-                let imageOutput = AVCapturePhotoOutput()
-                session.addOutput(imageOutput)
+            let imageOutput = AVCapturePhotoOutput()
+            session.addOutput(imageOutput)
 
-                self.session = session
-                session.startRunning()
-                print("session started")
-            } else {
-                print("no camera")
-            }
+            self.session = session
+            session.startRunning()
         } catch {
-          print("error")
+          print("VSVS: failed to start the video capture session")
         }
     }
 }

        super.viewDidLoad()

        guard let mtkView = self.view as? MTKView else {
            print("VSVS view is not an MTKView")
            return
        }
        

                if let metalTexture = metalTexture, status == kCVReturnSuccess {
                    renderer?.texture = metalTexture
                } else {
                    print("VSVS: failed to create texture")
                }
            }
        } else {
