     }
     
     internal func setupPixelBufferPoolIfNecessary(_ pixelBuffer: CVPixelBuffer, orientation: CGImagePropertyOrientation) {
+        guard self._pixelBufferPool == nil else {
+            return
+        }
+        
         let formatType = CVPixelBufferGetPixelFormatType(pixelBuffer)
         let width = CVPixelBufferGetWidth(pixelBuffer)
         let height = CVPixelBufferGetHeight(pixelBuffer)
-        
-        guard self._pixelBufferPool == nil else {
-            return
-        }
         
         // check dimension/orientation/format changed
         if width == self._bufferWidth && height == self._bufferHeight && formatType == self._bufferFormatType {

    public convenience init(view: ARSCNView) {
        self.init()
        
        #if !( targetEnvironment(simulator) )
        self._device = view.device
        self._renderer = SCNRenderer(device: view.device, options: nil)
        self._renderer?.scene = view.scene
        #endif
        
        self._arView = view
        self._presentationFrame = view.bounds
    }
    #endif
    

            return
        }
        
        let options : [CIContextOption : Any] = [.outputColorSpace : CGColorSpaceCreateDeviceRGB(),
                                                 .outputPremultiplied : true,
                                                 .useSoftwareRenderer : NSNumber(booleanLiteral: false)]
