I would like to render a composition into an offscreen buffer in order
to be able to pass it to other compositions (like it is done in the
performer sample application). However, I would like to show the
result
of the composition in a preview view. The approach I have taken is to
use the CIView from the CI sample application, but I'm not sure if
this
is the most efficient way. Do I have to share the opengl contexts from
the offscreen buffer and the CIView? Can I directly access the
CVImageBufferRef and render it without passing through a CIImage?
yes, you can do that. Going though CI requires a fragment shaders
capable card, and since you just want to display the image, that
might not be the best solution. Here's what I would try instead:
Create another QCView to display the preview and load a composition
on it that simply displays an image: billboard will do and publish
the image input. Then, just pass the CVOpenGLBuffers to the input
image of the QCView.
