[Xorg] Re: X on OpenGL

Andy Sy andy at nospam.com
Tue Jul 13 04:18:32 PDT 2004

John Dennis wrote:

> Assigning the task of rendering for a windowing system to a rendering
> API which is windowing system neutral is completely consistent with the
> design goals of OpenGL.

The task in question is not merely rendering /for/ a windowing system.
It's rendering /the/ windowing system itself.  So again, the question
is, how suitable and how efficiently implemented is the OpenGL API
(built mainly with *3D* rendering in mind) for the task of _implementing_
a 2D windowing system.

My main worries are that 2D operations might be klunkier or less
efficient (considering the horror stories I've heard about the
performance of glXXXXPixels()) to execute using the OpenGL API.

If Quartz Extreme is indeed completely implemented via the OpenGL
API then that bodes well.  On the other hand, if it relies on even
one or two non-standard or non-OpenGL API functions / extensions
for basic or key functionality, then it is virtually a sure bet that
the designers of Quartz Extreme have found out that one cannot
efficiently or elegantly implement a windowing system on top of
/pure/ OpenGL (i.e. that the OpenGL API lacks certain suitable
kinds of calls for such a task).

reply to: a n d y @ n e t f x p h . c o m

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