[GEM-dev] RGBA confusion...

[IOhannes m zmoelnig]

chris clepper wrote:
> The problem with the pix_ objects is the MMX code on is fixed to a 
> different order than what OSX Intel uses.  For some objects this makes 
> no difference, but others require the components in a specific order.  
> So to fix some bug complaints I swapped the byte order to match the MMX 
> code, but this broke other things so it was switched back.  Perhaps 
> defining some MMX/SSE macros for the order would sort this out?
> 
> I don't think there are any GL alpha problems at all. 

the problem is most likely not with openGL.
however, the problem is not only with SIMD code, even after your changes.

a test of [pix_mask] revealed a lot of weirdnesses (but unfortunately i 
don't have access to my test-patch right now, so i try to reconstruct it 
by heart)
the tests have been done on an i686 (OSX-10.4.?)
i got different results when using [pix_image], [pix_film] and 
[pix_video] as pix-source; i also get different results when using 
[colorspace RGBA( vs [pix_rgba]
the results differ in both swapping color-channels _and_ having 
different "types". iirc, images in RGBA space with type 
GL_UNSIGNED_INT_8_8_8_8_REV where almost certain to yield blueish 
results with alpha mask not working.
finally, [pix_mask] does _not_ involve any MMX/SSE2 code.

i am pretty sure that on macIntel images of type GL_BGRA_EXT are _not_ 
of type GL_UNSIGNED_INT_8_8_8_8_REV, is this correct?

anyhow, i thought before i start thinking about changing things and 
making them worse, i would rather now what the target layout of the 
colors is, that's why i started the wiki.

and yes, i also think that having some macros for the SSE/MMX code will 
help us (but i am not that far yet...)

fgmadsr
IOhannes