将原始IOS相机数据上传到纹理
问题描述:
我们在IOS上使用AVCaptureDevice
来扫描QR码。我们将相机的输出使用AVCaptureMetadataOutput
传递给识别QR码的代码,目前我们还将该相机作为独立视图显示在Open GL视图上。不过,我们现在希望其他图形显示在相机预览中,因此我们希望能够将相机数据加载到我们的Open GL纹理中。将原始IOS相机数据上传到纹理
那么,有没有一种方法来从相机
此获取原始RGB数据的代码(下)我们使用初始化捕获设备和看法。
我们如何修改它以访问RGB数据,以便我们可以将其加载到我们的GL纹理之一上?我们使用C++/Objective C的
感谢
肖恩南
self.captureSession = [[AVCaptureSession alloc] init];
NSError *error;
// Set camera capture device to default and the media type to video.
AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
// Set video capture input: If there a problem initialising the camera, it will give am error.
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
if (!input)
{
NSLog(@"Error Getting Camera Input");
return;
}
// Adding input souce for capture session. i.e., Camera
[self.captureSession addInput:input];
AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
// Set output to capture session. Initalising an output object we will use later.
[self.captureSession addOutput:captureMetadataOutput];
// Create a new queue and set delegate for metadata objects scanned.
dispatch_queue_t dispatchQueue;
dispatchQueue = dispatch_queue_create("scanQueue", NULL);
[captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
// Delegate should implement captureOutput:didOutputMetadataObjects:fromConnection: to get callbacks on detected metadata.
[captureMetadataOutput setMetadataObjectTypes:[captureMetadataOutput availableMetadataObjectTypes]];
// Layer that will display what the camera is capturing.
self.captureLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
[self.captureLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
gCameraPreviewView= [[[UIView alloc] initWithFrame:CGRectMake(gCamX1, gCamY1, gCamX2-gCamX1, gCamY2-gCamY1)] retain];
[self.captureLayer setFrame:gCameraPreviewView.layer.bounds];
[gCameraPreviewView.layer addSublayer:self.captureLayer];
UIViewController * lVC = [[[UIApplication sharedApplication] keyWindow] rootViewController];
[lVC.view addSubview:gCameraPreviewView];
答
你不需要直接访问RGB摄像头帧,使之作为纹理,因为IOS支持纹理缓存,其比你快。
- (void) writeSampleBuffer:(CMSampleBufferRef)sampleBuffer ofType:(NSString *)mediaType pixel:(CVImageBufferRef)cameraFrame time:(CMTime)frameTime;
在回调方法
,则可以使用下面
CVOpenGLESTextureCacheCreate(...)
CVOpenGLESTextureCacheCreateTextureFromImage(...)
答
那些参数和功能。在我们从CMSampleBuffer转换成原始数据的结束生成纹理(所以我们可以上传到GL纹理) 喜欢这个。它需要一点时间,但对我们的目的来说足够快。
如果有任何的改进,我会很高兴知道:)
肖恩
- (void)captureOutput:(AVCaptureFileOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection;
{
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CIImage *ciImage = [CIImage imageWithCVPixelBuffer:imageBuffer];
if(!self.context)
{
self.context = [CIContext contextWithOptions:nil]; //only create this once
}
int xsize= CVPixelBufferGetWidth(imageBuffer);
int ysize= CVPixelBufferGetHeight(imageBuffer);
CGImageRef videoImage = [self.context createCGImage:ciImage fromRect:CGRectMake(0, 0, xsize, ysize)];
UIImage *image = [[UIImage alloc] initWithCGImage:videoImage];
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
if(!colorSpace)
{
return ;
}
size_t bitsPerPixel = 32;
size_t bitsPerComponent = 8;
size_t bytesPerPixel = bitsPerPixel/bitsPerComponent;
size_t bytesPerRow = xsize * bytesPerPixel;
size_t bufferLength = bytesPerRow * ysize;
uint32_t * tempbitmapData = (uint32_t *)malloc(bufferLength);
if(!tempbitmapData)
{
CGColorSpaceRelease(colorSpace);
return ;
}
CGContextRef cgcontext = CGBitmapContextCreate(tempbitmapData, xsize, ysize, bitsPerComponent, bytesPerRow, colorSpace, kCGImageAlphaPremultipliedLast);
if(!cgcontext)
{
free(tempbitmapData);
return;
}
CGColorSpaceRelease(colorSpace);
CGRect rect = CGRectMake(0, 0, xsize, ysize);
CGContextDrawImage(cgcontext, rect, image.CGImage);
unsigned char *bitmapData = (unsigned char *)CGBitmapContextGetData(cgcontext); // Get a pointer to the data
CGContextRelease(cgcontext);
[image release];
CallbackWithData((unsigned int *)bitmapData,xsize,ysize); //send data
free(bitmapData);
CGImageRelease(videoImage);
}