Why run xserver on the OpenGL API?

[Allen Akin]

On Sun, Jan 04, 2004 at 05:12:35PM -0600, Marcelo E. Magallon wrote:
|  I was trying to avoid the "but this can be done with a fragment
|  program" mantra :-)

I apologize for repeating it so frequently. :-)  I want to make sure
everyone's thinking about the implications of programmability at so many
levels of the system, though.  It will have significant effects on the
application programming interfaces, the internal systems programming
interfaces, and the system's architectural tradeoffs.  The commercial
folks are dealing with all these issues; if we don't, what we build runs
a significant risk of being obsolete from the beginning.

|  Logic operations (bitwise operations) are not supported by the current
|  ARB_fragment_program specification.  ...

Right.

|                                   ... I can't recall if the SLang spec
|  says something about it.

I don't recall either, but I know from the ARB discussions that people
are debating it intensely.  If I remember correctly, color-channel logic
ops, like blending to framebuffer destinations, are currently performed
downstream of the fragment processors.  Moving them up to the fragment
processing stage requires not only solving the read/modify/write
performance problems you mentioned elsewhere in your note, but also
defining the semantics of bitwise operations on floating-point color
values.

Allen