Re: The big divide - graphics contexts and window servers

[Jeff Teunissen]

Pete French wrote:

> > OpenGL is designed for 3D, and it's not happy with 2D. Most GL
> > implementations don't accelerate 2D operations beyond throwing a quad
> > on the screen, and some even leave it incomplete.
> 
> Are you sure about this ? I thought there wernt concepts of '2D' and
> '3D' in OpenGL - you just provide a transformation matrix, and if that
> happens to be 'flat' so that the points get mapped onto one plane then
> you have 2D and the library knowns nothing about it.

Of course the library knows everything about it, the library is what has to
draw it!  The difference is there are fast paths and slow paths in any GL
pipeline, and "2D" stuff is usually slow-pathed because there's usually not
enough of it to matter.

> > Also throw in the fact that on most non-professional
> > implementations/cards, you can only have one direct-rendering window
> > at a time.
> 
> Somewhat irrelevent - GLUT allows you to open and render into multiple
> windows, so any implementation oif GLUT will let you do this.

I didn't say "you can only have one window at a time". I said "one
direct-rendering window". DRI doesn't do multiple direct contexts. Neither
does NVIDIA.

Anyone can draw to multiple windows. That's dead simple. Drawing to multiple
windows and getting them both accelerated, that's a little more of a problem.

> If people buy cheap harrdware that does a crap job of rendering it then
> thats not our fault or our problem. The top layers should be independent
> of the hardware. After all a lot of systems will be using something like
> Mesa anyway as they dont have hardware GL. Its a bonus if it exists, but
> the fact that it doesnt or is badly implemented shouldnt bother us
> unduly.

Systems without hardware GL would be an order of magnitude slower. We're not
talking about "ohh, this is a little choppy" -- slide show city.

-- 
| Jeff Teunissen  -=-  Pres., Dusk To Dawn Computing  -=-  deek @ d2dc.net
| GPG: 1024D/9840105A   7102 808A 7733 C2F3 097B  161B 9222 DAB8 9840 105A
| Core developer, The QuakeForge Project        http://www.quakeforge.net/
| Specializing in Debian GNU/Linux              http://www.d2dc.net/~deek/