快速的开发一个完整的iOS直播App(美颜)

- (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];  
    }  

}