Reply To: Syphon -> CoreImage

[Andrea Cremaschi]

well, actually what I am trying to do is to copy syphonimages in CPU memory space (i.e. in a NSBitmapImageRep). Since I am making some processing in realtime I need to do this in the fastest possible way. I tried to reuse some of the code that I wrote for a simple QTKit stream ( where CIImages were created with [CIImage imageWithCVImageBuffer:pixelBuffer] method), but the result now is: black images. Why? Here is the pseudo code:

CGLContextObj cgl_ctx = [[openGLRenderContext CGLContextObj]; // openGLRenderContext is a previously created openGL context
SyphonImage *image = [[syClient newFrameImageForContext:cgl_ctx] autorelease];
	GLuint texture = [image textureName];
	NSSize imageSize = [image textureSize];

    const CGRect r = {.origin = {0, 0}, .size = {imageSize.width, imageSize.height}};
    CIImage *ciImage = [CIImage imageWithTexture:texture
											size:r.size
										 flipped:YES
									  colorSpace:cs];

		NSBitmapImageRep* bitmap=[[[NSBitmapImageRep alloc]
													   initWithBitmapDataPlanes: nil
													   pixelsWide: [ciImage extent].size.width
													   pixelsHigh: [ciImage extent].size.height
													   bitsPerSample:8
													   samplesPerPixel:4
													   hasAlpha: YES
													   isPlanar: NO
													   colorSpaceName: NSCalibratedRGBColorSpace
													   bytesPerRow: 0
													   bitsPerPixel:32] autorelease] ;

							NSGraphicsContext * graphicsContext = [NSGraphicsContext
														   graphicsContextWithBitmapImageRep: bitmap] ;

							CGRect rect  = [ciImage extent];
							[[graphicsContext CIContext] drawImage: ciImage
												   atPoint: CGPointZero
												  fromRect: rect];

I suppose that it is not working because [graphicsContext CIContext] is not shared with cgl_ctx. So, how to proceed? Which is the “best practice”??