// 捕获音视频
- (void)setupCaputureVideo
{
    // 1.创建捕获会话,必须要强引用，否则会被释放
    AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
    _captureSession = captureSession;

    // 2.获取摄像头设备，默认是后置摄像头
    AVCaptureDevice *videoDevice = [self getVideoDevice:AVCaptureDevicePositionFront];

    // 3.获取声音设备
    AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];

    // 4.创建对应视频设备输入对象
    AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];
    _currentVideoDeviceInput = videoDeviceInput;

    // 5.创建对应音频设备输入对象
    AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:nil];

    // 6.添加到会话中
    // 注意“最好要判断是否能添加输入，会话不能添加空的
    // 6.1 添加视频
    if ([captureSession canAddInput:videoDeviceInput]) {
        [captureSession addInput:videoDeviceInput];
    }
    // 6.2 添加音频
    if ([captureSession canAddInput:audioDeviceInput]) {
        [captureSession addInput:audioDeviceInput];
    }

    // 7.获取视频数据输出设备
    AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    // 7.1 设置代理，捕获视频样品数据
    // 注意：队列必须是串行队列，才能获取到数据，而且不能为空
    dispatch_queue_t videoQueue = dispatch_queue_create("Video Capture Queue", DISPATCH_QUEUE_SERIAL);
    [videoOutput setSampleBufferDelegate:self queue:videoQueue];
    if ([captureSession canAddOutput:videoOutput]) {
        [captureSession addOutput:videoOutput];
    }

    // 8.获取音频数据输出设备
    AVCaptureAudioDataOutput *audioOutput = [[AVCaptureAudioDataOutput alloc] init];
    // 8.2 设置代理，捕获视频样品数据
    // 注意：队列必须是串行队列，才能获取到数据，而且不能为空
    dispatch_queue_t audioQueue = dispatch_queue_create("Audio Capture Queue", DISPATCH_QUEUE_SERIAL);
    [audioOutput setSampleBufferDelegate:self queue:audioQueue];
    if ([captureSession canAddOutput:audioOutput]) {
        [captureSession addOutput:audioOutput];
    }

    // 9.获取视频输入与输出连接，用于分辨音视频数据
    _videoConnection = [videoOutput connectionWithMediaType:AVMediaTypeVideo];

    // 10.添加视频预览图层
    AVCaptureVideoPreviewLayer *previedLayer = [AVCaptureVideoPreviewLayer layerWithSession:captureSession];
    previedLayer.frame = [UIScreen mainScreen].bounds;
    [self.view.layer insertSublayer:previedLayer atIndex:0];
    _previedLayer = previedLayer;

    // 11.启动会话
    [captureSession startRunning];
}

// 指定摄像头方向获取摄像头
- (AVCaptureDevice *)getVideoDevice:(AVCaptureDevicePosition)position
{
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *device in devices) {
        if (device.position == position) {
            return device;
        }
    }
    return nil;
}

#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate
// 获取输入设备数据，有可能是音频有可能是视频
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    if (_videoConnection == connection) {
        NSLog(@"采集到视频数据");
    } else {
        NSLog(@"采集到音频数据");
    }
}

// 切换摄像头
- (IBAction)toggleCapture:(id)sender {

    // 获取当前设备方向
    AVCaptureDevicePosition curPosition = _currentVideoDeviceInput.device.position;

    // 获取需要改变的方向
    AVCaptureDevicePosition togglePosition = curPosition == AVCaptureDevicePositionFront?AVCaptureDevicePositionBack:AVCaptureDevicePositionFront;

    // 获取改变的摄像头设备
    AVCaptureDevice *toggleDevice = [self getVideoDevice:togglePosition];

    // 获取改变的摄像头输入设备
    AVCaptureDeviceInput *toggleDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:toggleDevice error:nil];

    // 移除之前摄像头输入设备
    [_captureSession removeInput:_currentVideoDeviceInput];

    // 添加新的摄像头输入设备
    [_captureSession addInput:toggleDeviceInput];

    // 记录当前摄像头输入设备
    _currentVideoDeviceInput = toggleDeviceInput;

}

if ([currentDevice isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
    CGPoint autofocusPoint = CGPointMake(0.5f, 0.5f);
    [currentDevice setFocusPointOfInterest:autofocusPoint];
    [currentDevice setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
}

if ([currentDevice isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) {
    CGPoint exposurePoint = CGPointMake(0.5f, 0.5f);
    [currentDevice setExposurePointOfInterest:exposurePoint];
    [currentDevice setExposureMode:AVCaptureExposureModeContinuousAutoExposure];
}

- (void)viewDidLoad {
    [super viewDidLoad];

    // 创建视频源
    // SessionPreset:屏幕分辨率，AVCaptureSessionPresetHigh会自适应高分辨率
    // cameraPosition:摄像头方向
    GPUImageVideoCamera *videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPresetHigh cameraPosition:AVCaptureDevicePositionFront];
     videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
    _videoCamera = videoCamera;

    // 创建最终预览View
    GPUImageView *captureVideoPreview = [[GPUImageView alloc] initWithFrame:self.view.bounds];
    [self.view insertSubview:captureVideoPreview atIndex:0];

    // 创建滤镜：磨皮，美白，组合滤镜
    GPUImageFilterGroup *groupFilter = [[GPUImageFilterGroup alloc] init];

    // 磨皮滤镜
    GPUImageBilateralFilter *bilateralFilter = [[GPUImageBilateralFilter alloc] init];
    [groupFilter addTarget:bilateralFilter];
    _bilateralFilter = bilateralFilter;

    // 美白滤镜
    GPUImageBrightnessFilter *brightnessFilter = [[GPUImageBrightnessFilter alloc] init];
    [groupFilter addTarget:brightnessFilter];
    _brightnessFilter = brightnessFilter;

    // 设置滤镜组链
    [bilateralFilter addTarget:brightnessFilter];
    [groupFilter setInitialFilters:@[bilateralFilter]];
    groupFilter.terminalFilter = brightnessFilter;

    // 设置GPUImage响应链，从数据源 => 滤镜 => 最终界面效果
    [videoCamera addTarget:groupFilter];
    [groupFilter addTarget:captureVideoPreview];

    // 必须调用startCameraCapture，底层才会把采集到的视频源，渲染到GPUImageView中，就能显示了。
    // 开始采集视频
    [videoCamera startCameraCapture];
}

- (IBAction)brightnessFilter:(UISlider *)sender {
    _brightnessFilter.brightness = sender.value;
}

- (IBAction)bilateralFilter:(UISlider *)sender {
    // 值越小，磨皮效果越好
    CGFloat maxValue = 10;
    [_bilateralFilter setDistanceNormalizationFactor:(maxValue - sender.value)];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    // 创建视频源
    // SessionPreset:屏幕分辨率，AVCaptureSessionPresetHigh会自适应高分辨率
    // cameraPosition:摄像头方向
    GPUImageVideoCamera *videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPresetHigh cameraPosition:AVCaptureDevicePositionFront];
    videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
    _videoCamera = videoCamera;

    // 创建最终预览View
    GPUImageView *captureVideoPreview = [[GPUImageView alloc] initWithFrame:self.view.bounds];
    [self.view insertSubview:captureVideoPreview atIndex:0];
    _captureVideoPreview = captureVideoPreview;

    // 设置处理链
    [_videoCamera addTarget:_captureVideoPreview];

    // 必须调用startCameraCapture，底层才会把采集到的视频源，渲染到GPUImageView中，就能显示了。
    // 开始采集视频
    [videoCamera startCameraCapture];

}

- (IBAction)openBeautifyFilter:(UISwitch *)sender {

    // 切换美颜效果原理：移除之前所有处理链，重新设置处理链
    if (sender.on) {

        // 移除之前所有处理链
        [_videoCamera removeAllTargets];

        // 创建美颜滤镜
        GPUImageBeautifyFilter *beautifyFilter = [[GPUImageBeautifyFilter alloc] init];

        // 设置GPUImage处理链，从数据源 => 滤镜 => 最终界面效果
        [_videoCamera addTarget:beautifyFilter];
        [beautifyFilter addTarget:_captureVideoPreview];

    } else {

        // 移除之前所有处理链
        [_videoCamera removeAllTargets];
        [_videoCamera addTarget:_captureVideoPreview];
    }
}