Quartz Composer pixel formats and context handling

Hey there guys,

we are trying to implement some sort of pipeline with custom QCPlugins and CIFilters within QC. It all worked out well at first but we ran into problems lately.

The main issue is that we don't know how the CGLContext operates in conjunction with pixel formats. We want that all our components are working on floating point buffers to get the maximum quality possible.

However, we don't understand how Quartz Composer handles the input and output image buffers/textures. It seems that regardless of how we set the output image, it gets scaled down to RGBA 8 bit per component.

So, to phrase a question: is there any way to tell QC that it should use RGBA floating point buffers? Are the input and output images converted to fit the pixel format QC expects?

Maybe someone can shed some light on this! It's really confusing. Especially as Apple is using the word "pixel format" in CGL and QCPlugIn with totally different meanings.

Thanks in advance!!

Flo