我使用GPUImage库和以下代码创建了一个简单的绿屏:importUIKitimportGPUImageclassCaptureViewController:UIViewController{varvideoCamera:GPUImageVideoCamera?varfilter:GPUImageChromaKeyFilter?@IBOutletweakvarcameraView:GPUImageView!overridefuncviewDidLoad(){super.viewDidLoad()cameraView.backgroundColor=UIColor.clearColor