CIContext drawImage导致EXC_BAD_ACCESS - iOS 6

Question

我试图将一个简单的核心图像过滤器应用于实时相机输入。我认为我的代码是好的，但在captureOutput方法中使用方法drawImage:inRect:fromRect会导致EXC_BAD_ACCESS或[__NSCFNumber drawImage:inRect:fromRect:]: unrecognized选择器，这让我认为在尝试调用drawImage时我的上下文已被释放。这对我来说没有意义，因为我的CIContext是班级成员。

这个问题似乎不是来自OpenGL，因为我尝试了一个简单的上下文（而不是从EAGLContext创建），我也遇到了同样的问题。

我使用ios 6在iphone 5上测试它，因为相机无法在模拟器上工作。

你能帮我解答吗？非常感谢您的宝贵时间

我有我的.h文件：

<!-- language: c# --> 

    // CameraController.h 

    #import <UIKit/UIKit.h> 
    #import <OpenGLES/EAGL.h> 
    #import <AVFoundation/AVFoundation.h> 
    #import <GLKit/GLKit.h> 
    #import <CoreMedia/CoreMedia.h> 
    #import <CoreVideo/CoreVideo.h> 
    #import <QuartzCore/QuartzCore.h> 
    #import <CoreImage/CoreImage.h> 
    #import <ImageIO/ImageIO.h> 

    @interface CameraController : GLKViewController <AVCaptureVideoDataOutputSampleBufferDelegate>{ 

     AVCaptureSession *avCaptureSession; 
     CIContext *coreImageContext; 
     CIContext *ciTestContext; 
     GLuint _renderBuffer; 
     EAGLContext *glContext; 
    } 

    @end 

和我的.m文件

<!-- language: c# --> 

    // CameraController.m 

    #import "CameraController.h" 

    @interface CameraController() 

    @end 

    @implementation CameraController 

    - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
    { 
     self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
     if (self) { 

     } 
     return self; 
    } 

    - (void)viewDidLoad 
    { 
     [super viewDidLoad]; 

     // Initialize Open GL ES2 Context 
     glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; 
     if (!glContext) { 
      NSLog(@"Failed to create ES context"); 
     } 
     [EAGLContext setCurrentContext:nil]; 

     // Gets the GL View and sets the depth format to 24 bits, and the context of the view to be the Open GL context created above 
     GLKView *view = (GLKView *)self.view; 
     view.context = glContext; 
     view.drawableDepthFormat = GLKViewDrawableDepthFormat24; 

     // Creates CI Context from EAGLContext 
     NSMutableDictionary *options = [[NSMutableDictionary alloc] init]; 
     [options setObject: [NSNull null] forKey: kCIContextWorkingColorSpace]; 
     coreImageContext = [CIContext contextWithEAGLContext:glContext options:options]; 

     glGenRenderbuffers(1, &_renderBuffer); 
     glBindRenderbuffer(GL_RENDERBUFFER, _renderBuffer); 

     // Initialize Video Capture Device 
     NSError *error; 
     AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; 
     AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error]; 

     // Initialize Video Output object and set output settings 
     AVCaptureVideoDataOutput *dataOutput = [[AVCaptureVideoDataOutput alloc] init]; 

     [dataOutput setAlwaysDiscardsLateVideoFrames:YES]; 
     [dataOutput setVideoSettings:[NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] 
                    forKey:(id)kCVPixelBufferPixelFormatTypeKey]]; 


     // Delegates the SampleBuffer to the current object which implements the AVCaptureVideoDataOutputSampleBufferDelegate interface via the captureOutput method 
     [dataOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()]; 

     // Initialize the capture session, add input, output, start urnning 
     avCaptureSession = [[AVCaptureSession alloc] init]; 
     [avCaptureSession beginConfiguration]; 
     [avCaptureSession setSessionPreset:AVCaptureSessionPreset1280x720]; 
     [avCaptureSession addInput:input]; 
     [avCaptureSession addOutput:dataOutput]; 
     [avCaptureSession commitConfiguration]; 
     [avCaptureSession startRunning]; 


    } 

    -(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection { 

     // Creates a CIImage from the sample buffer of the camera frame 
     CVPixelBufferRef pixelBuffer = (CVPixelBufferRef)CMSampleBufferGetImageBuffer(sampleBuffer); 
     CIImage *inputImage = [CIImage imageWithCVPixelBuffer:pixelBuffer]; 

     // Creates the relevant filter 
     CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone"]; 
     [filter setValue:inputImage forKey:kCIInputImageKey]; 
     [filter setValue:[NSNumber numberWithFloat:0.8f] forKey:@"InputIntensity"]; 

     // Creates a reference to the output of the filter 
     CIImage *result = [filter valueForKey:kCIOutputImageKey]; 

     // Draw to the context 
     [coreImageContext drawImage:result inRect:[result extent] fromRect:[result extent]]; // 5 

     [glContext presentRenderbuffer:GL_RENDERBUFFER]; 
    } 

    - (void)didReceiveMemoryWarning 
    { 
     [super didReceiveMemoryWarning]; 
     // Dispose of any resources that can be recreated. 
    } 


    @end 

Answer 1

在您的viewDidLoad方法，您有：

coreImageContext = [CIContext contextWithEAGLContext:glContext options:options]; 

如果您想在captureOutput方法中使用它，则需要保留coreImageContext。