From: Brian P. <br...@tu...> - 2003-02-06 23:32:17
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Alexander Stohr wrote: > first let me separate the framebuffer data from GL data > by four more spaces. > > > >>>>> MGA > > >>>>> r g b a amask bsz ar ag ab aa Xvisual dpth > > >>>>> 5 6 5 0 00000000 16 16 16 16 0 16 > > >>>>> 8 8 8 8 00000000 32 16 16 16 0 24 > > >>> > > >>> alphaMask should be 0xff000000. > > >> > > >> In the argb8888 READ_RGBA in mgaspan.c, alpha is always > > returned as > > >> 255. One or the other of these is wrong. > > > > > > Hmmm, I don't remember if the g200/400 supports dest alpha. > > The span > > > functions would seem to indicate "no". > > > > I've changed the mga_dri.c to report 0 for alpha bits, and 24 > > as the buffer size. > > Then result should be: > > MGA > r g b a amask bsz ar ag ab aa Xvisual dpth > 5 6 5 0 00000000 16 16 16 16 0 16 > 8 8 8 0 00000000 24 16 16 16 0 24 Right. > it seems that no one never ever tried that alpha bits > or used the bsz value. Most likely, the later. I've never seen any application care about GLX_BUFFER_SIZE. > > >>>>> GLINT > > >>>>> r g b a amask bsz ar ag ab aa Xvisual dpth > > >>>>> 5 5 5 5 000f1000 16 16 16 16 0 15 (pScrn->depth) > > >>>>> 8 8 8 0 00000000 32 16 16 16 0 24 (pScrn->depth) > > >>>> > > >>>> This might be right. > > >>> > > >>> Looks OK. > > > > > > >> Shouldn't the buffer size be 24 here? > > > > > > Ooops, yes. > > > > Fixed. > > Assumed result: > > GLINT > r g b a amask bsz ar ag ab aa Xvisual dpth > 5 5 5 5 000f1000 16 16 16 16 0 15 (pScrn->depth) > 8 8 8 0 00000000 24 16 16 16 0 24 (pScrn->depth) > > Hey and why does 5+5+5+5 = 20, but sum up to 24 in your sheme? Huh??? It looks like 5+5+5+5 was mistakenly adding to 16, not 24 (or 20). It's not my "scheme" - I didn't write that code! > i mean the alpha bits would be only 1 bit (my prefrered thing, matches > Xvis) > or the bsz is truely 24 for the first line. (dont like that) > > here my prefered fix: > > GLINT > r g b a amask bsz ar ag ab aa Xvisual dpth > 5 5 5 1 00008000 16 16 16 16 0 15 (pScrn->depth) > 8 8 8 0 00000000 24 16 16 16 0 24 (pScrn->depth) > > sorry i dont have that hardware handy or any specs nearby. Me neither. I don't know what it's supposed to really be. The span fallback functions treat the first mode as a 565 RGB visual. I think Alan H. did some work on this driver a while back. Do you remember anything about this? -Brian |