Does anyone know if it’s possible to use OpenGL to draw directly to the video card without having to go through X? In other words, I’m at an 80x24 console and, for example, I’d like to draw a cube onto my screen without having to fire up X.
miranda
No, you have to fire up X perhaps with the exception of Mesa with Voodoo cards.
hello!
No, you have to fire up X perhaps with the exception of Mesa with Voodoo cards.
almost, isn’t it fact, that you need a driver to access to a piece of hardware under linux?
recently i had had a discussion about this matter: mesa is an opengl implementation and no hardware driver.
X has access to certain hardware resources, which enables it to modify them directly.
afaik, before version 4.0, X had only two video-hardware interfaces: the common and the one which enabled the voodoo cards to write the video-chip.
now, the voodoo interface was extended (don’t know exactly, though) to the dri/drm, which means there’s a kernel module and an interface for X.
and finally there’s this GLX interface for nvidia cards for example.
as i said, i don’t know this stuff exactly, but one thing is sure: X is only a userspace program with certain privileges. so you can write a similar driver, but it’s a huge effort, i’d say…
miranda, i hope you’re not too disappointed, but you might try the aalib… (don’t know the website)
hope this helps!
bye,
Tolga.
Actually there is a port of the dri to SDL on the frame buffer. It is supposed to work only with ati radeaons for the moment, but should be no problem to port to others.
http://www.opengl.org/discussion_boards/ubb/Forum4/HTML/000375.html
Just search for “frame buffer” on opengl.org
I found the link here
Tolga, I guess you are right about Mesa and drivers but I think they are pretty integrated. See the comment on the DRI driver download page for example http://dri.sourceforge.net/
I think of direct rendering as a way to bypass the X system and talk directly to the hardware. Here is some documentation about how OpenGL integrates with the X window system: http://toolbox.sgi.com/linux/documents/OpenGL/overviews.html#mjkOiX
almost (hum, you’d rather sign in with your real name, since it’s rather strange to call you almost),
tnx for your reply and links, they’re very useful. nevertheless, they are not really mesa specific, but rather glx. i’d guess, that glut for example uses the same routines (api) to access to opengl hardware.
Sorry for the silly username. Perhaps can I come up with something better in the future. 
Yes, you are right the documentation is not Mesa specific. It is the same for SGI, NVidia and probably all OpenGL with X implementations.
no, your name is not really stoopid, but …erm … unusual. tell me how you’ll call yourself.
anyway, that document is quite good, though it’s a bit old…
l8ers…
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