On Fri, 9 May 2003 zmoelnig@iem.at wrote:
unfortunately i am not sure, whether the only use of [pix_rgba] is for conversion into "native" colour-space. sometimes i really like having an alpha-channel....
I was thinking the "native" colorspace is with alpha channel, but with yuv this is not the case, as I have heard. (In the film example pix_rgba was used to convert from RGB to RGBA, which I thought is a bit strange).
yes the buffer should be filled with R+G+B+A in order for the pix_objects to process the data. GEM currently has no way to work with a 24bpp RGB buffer. so it makes no sense to have the pix_film/video object deliver anything but 32bpp buffers.
Yes the alpha channel is quite nice in several circumstances .. will this be lost on OSX when there is no pix_rgba ?
nope. the native mac pixel format is ARGB and that's what the pix_film/video objects put in the buffers. there's an ifdef for OSX that changes the ordering of the channels and GL_BGRA_EXT is the corresponding GL format.
cgc
Guenter