What is the reason to pass the texture through `passthroughFragment` shader before rendering to view to recording to video file?

[sbelmeha]

For example here:

func renderIntoPixelBuffer(_ pixelBuffer:CVPixelBuffer, texture:Texture) {
        guard let pixelBufferBytes = CVPixelBufferGetBaseAddress(pixelBuffer) else {
            print("Could not get buffer bytes")
            return
        }

        let bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer)

        let outputTexture:Texture
        if (Int(round(self.size.width)) != texture.texture.width) && (Int(round(self.size.height)) != texture.texture.height) {
            let commandBuffer = sharedMetalRenderingDevice.commandQueue.makeCommandBuffer()

            outputTexture = Texture(device:sharedMetalRenderingDevice.device, orientation: .portrait, width: Int(round(self.size.width)), height: Int(round(self.size.height)), timingStyle: texture.timingStyle)

            commandBuffer?.renderQuad(pipelineState: renderPipelineState, inputTextures: [0:texture], outputTexture: outputTexture)
            commandBuffer?.commit()
            commandBuffer?.waitUntilCompleted()
        } else {
            outputTexture = texture
        }

        let region = MTLRegionMake2D(0, 0, outputTexture.texture.width, outputTexture.texture.height)

        outputTexture.texture.getBytes(pixelBufferBytes, bytesPerRow: bytesPerRow, from: region, mipmapLevel: 0)
    }

Why do we need to render texture here by calling

 commandBuffer?.renderQuad(pipelineState: renderPipelineState, inputTextures: [0:texture], outputTexture: outputTexture)

if we already have an incoming one and can grab pixels from it?