Iphone 带角点检测的GPUImage叠加实时视频

尝试使用GPUImage获得一个基本过滤器，但不确定如何正确设置它，以便在检测角点时在实时视频提要上显示十字光标。我尝试将十字光标与视频一起添加到混合过滤器，然后将其添加到gpuimageview，但我得到的只是一个白色屏幕。有什么想法吗

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.



    videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
    videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;


    GPUImageView *filteredVideoView = (GPUImageView *)self.view;


    GPUImageCrosshairGenerator *crosshairGenerator = [[GPUImageCrosshairGenerator alloc] init];
    crosshairGenerator.crosshairWidth = 15.0;
    [crosshairGenerator forceProcessingAtSize:CGSizeMake(480.0, 640.0)];


    customFilter = [[GPUImageHarrisCornerDetectionFilter alloc] init];
    [customFilter setCornersDetectedBlock:^(GLfloat* cornerArray, NSUInteger cornersDetected, CMTime frameTime){
        [crosshairGenerator renderCrosshairsFromArray:cornerArray count:cornersDetected frameTime:frameTime];
        NSLog(@"corners: %u", cornersDetected);
    }];


    GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init];
    [blendFilter forceProcessingAtSize:CGSizeMake(480.0, 640.0)];

    [videoCamera addTarget:blendFilter];
    [crosshairGenerator addTarget:blendFilter];
    [blendFilter addTarget:filteredVideoView];


    [videoCamera startCameraCapture];

}

---

这就是您的代码在Swift 2.0中的显示方式

var liveCam:GPUImageVideoCamera!
var edgesDetector:GPUImageHarrisCornerDetectionFilter!
var crosshairGenerator:GPUImageCrosshairGenerator!
@IBOutlet weak var camView: GPUImageView!

override func viewDidLoad() {
    super.viewDidLoad()
    liveCam = GPUImageVideoCamera(sessionPreset: AVCaptureSessionPreset640x480, cameraPosition: .Back)
    liveCam.outputImageOrientation = .Portrait

    crosshairGenerator = GPUImageCrosshairGenerator()
    crosshairGenerator.crosshairWidth = 15
    crosshairGenerator.forceProcessingAtSize(CGSize(width: 480, height: 640))


    edgesDetector = GPUImageHarrisCornerDetectionFilter()
    edgesDetector.blurRadiusInPixels = 2 //Default value
    edgesDetector.threshold = 0.2 //Default value

    edgesDetector.cornersDetectedBlock = {(cornerArray:UnsafeMutablePointer<GLfloat>,cornersDetected:UInt,frameTime:CMTime) -> Void in
        self.crosshairGenerator.renderCrosshairsFromArray(cornerArray, count: cornersDetected, frameTime: frameTime)
        print("\(cornerArray) =-= \(cornersDetected) =-= \(frameTime)")

    }


    liveCam.addTarget(edgesDetector)
    edgesDetector.addTarget(crosshairGenerator)
    crosshairGenerator.addTarget(camView)

    liveCam.startCameraCapture()
}

var-liveCam:GPUImageVideoCamera！
var edgesDetector:GPUImageHarrisCornerDetectionFilter！
var crosshairGenerator:GPUImageCrosshairGenerator！
@IBVAR camView:GPUImageView！
重写func viewDidLoad（）{
super.viewDidLoad（）
liveCam=GPUImageVideoCamera（会话预设：AVCaptureSessionPreset640x480，cameraPosition:.Back）
liveCam.outputImageOrientation=.Portrait
crosshairGenerator=GPUImageCrosshairGenerator（）
crosshairGenerator.crosshairWidth=15
crosshairGenerator.forceProcessingAtSize（CGSize（宽：480，高：640））
edgesDetector=gpuimageriscornerDetectionFilter（）
edgesDetector.blurRadiusInPixels=2//默认值
edgesDetector.threshold=0.2//默认值
edgesDetector.cornersDetectedBlock={（cornerArray:UnsafemtablePointer，cornersDetected:UInt，frameTime:CMTime）->中的Void
self.crosshairGenerator.renderCrosshairsFromArray（cornerArray，计数：cornersDetected，帧时：帧时）
打印（“\（角落数组）=-=\（角落检测）=-=\（帧时间）”）
}
liveCam.addTarget（edgesDetector）
edgesDetector.addTarget（十字线生成器）
crosshairGenerator.addTarget（camView）
liveCam.startCameraCapture（）
}

结果是：

---

为什么不在GPUImageView之外添加十字线？就像使用另一个视图的覆盖一样？我的意思是在ViewController的视图中的GPUImageView顶部设置一个CAShapeLayer，并在其上绘制十字线。除非我遗漏了您试图实现的其他目标，否则这是非常简单的。我可能遗漏了它，但您何时将

customFilter

添加为

videoCamera

的目标？就目前的情况来看，看起来你并没有将帧送入角探测器。@BradLarson看起来就是这样。不确定如何正确添加所有内容