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mako
09-02-2003, 07:53 AM
Hi everyone,

is there an existing PBuffer class for Linux out there that can bind its color values directly to a texture? I think there were problems with the GLX version in the past? Has anything changed since then? I am using a GeForce FX. Can someone give me a link?


[This message has been edited by mako (edited 09-02-2003).]

jra101
09-02-2003, 08:40 AM
There is no OpenGL extension that allows you to render directly to a texture under Linux. There is one for Windows (WGL_ARB_render_texture) but there is no GLX equivalent yet.

azcoder
09-03-2003, 03:55 PM
WGL_ARB_PBUFFER is supported by nvidia under linux. Check out their hw_shadowmaps_simple.cpp from the sdk. Of course this example copies the depth values to the pbuffer, but you could also copy the color buffer instead.

good luck

azcoder
09-03-2003, 04:11 PM
Ooops - I meant GLX_SGIX_PBUFFER...Sorry. Anyway checkout the simple_pbuffer and simple_shared_pbuffer sample from the nvidia Linux sdk. The second one renders the glut teapot to a pbuffer and uses glCopyTexSubImage() to map it to a quad.

Happy coding

09-03-2003, 04:13 PM
no WGL* stuff is supported under linux. For pbuffers is GLX_SGIX_pbuffer supported by nvidia and also in the core GLX 1.3

09-03-2003, 04:14 PM
2 minuts to late http://www.opengl.org/discussion_boards/ubb/smile.gif

mako
09-03-2003, 05:28 PM
Yes, I already use this PBuffer extension and copy the color buffer about 16 times per frame via glCopyTexSubImage to a texture. Unfortunately, that consumes a lot of time. Time that I could spend elsewhere, if I could bind the PBuffer directly to a texture. Hope, there will be an appropriate extension in the near future.

nutball
09-04-2003, 12:24 AM
Yep, I'm waiting (patiently, so far) for GLX_ARB_render_texture, watching every set of ARB meeting minutes, watching every NVIDIA driver release... only to be disappointed.

It's almost enough to make me start writing software under Windows...

09-04-2003, 02:26 AM
There will be no GLX_ARB_render_texture, see http://groups.google.com/groups?hl=en&lr...r%2Bto%2Btextur (http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=bhjpf8%241l6l9%241%40fido.engr.sgi.com&rnum=9&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DISO-8859-1%26q%3Drender%2Bto%2Btextur) e%2Blinux%26meta%3D

We call glCopyTexSubImage for pbuffers but that is just a function name, it does not say what happens on the card. Calling the same function is faster for none pbuffers. If it was so easy as just to copy a pointer would nvidia have done that a long time ago. http://www.opengl.org/discussion_boards/ubb/smile.gif
Both ATi and nVidia has render_to_texture
and pbuffers under Windows and the difference is not that big.

I dont think that the superbuffer extension will solve all problems for todays hardware.

nutball
09-04-2003, 03:35 AM
*Sigh*, oh well, at least I can stop waiting. Or rather I can start waiting for superbuffers under Linux (let me guess, July 2004).

OK, Windows here I come...