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[News] Ogre 2.2.5 Cerberus Released and EGL Headless support!

Posted: Sat Feb 06, 2021 10:49 pm
by dark_sylinc

Re: [News] Ogre 2.2.5 Cerberus Released and EGL Headless support!

Posted: Sat Feb 06, 2021 11:32 pm
by paroj
not to be confused with 2000-era PBuffers which competed against FBOs
actually, these are exactly the 2000-era PBuffers. There is even EGL_TEXTURE_TARGET to be used instead of a FBO.
While NVidia does not support this, I could make it work using MESA and use EGL/PBuffers instead of FBOs on the GL1 RenderSystem, which still has code for rendering that way.

Re: [News] Ogre 2.2.5 Cerberus Released and EGL Headless support!

Posted: Sat Feb 06, 2021 11:53 pm
by mmozeiko
Please note Mesa SW at the time of writing supports up to OpenGL 3.3, which is the bare minimum to run Ogre. Some functionality may not be available.
This is not very accurate. For a few months mesa supports OpenGL 4.5 for llvmpipe software rasterizer. See the release notes for v20.3.0: https://docs.mesa3d.org/relnotes/20.3.0.html

Re: [News] Ogre 2.2.5 Cerberus Released and EGL Headless support!

Posted: Sun Feb 07, 2021 12:01 am
by dark_sylinc
mmozeiko wrote:
Sat Feb 06, 2021 11:53 pm
This is not very accurate. For a few months mesa supports OpenGL 4.5 for llvmpipe software rasterizer. See the release notes for v20.3.0: https://docs.mesa3d.org/relnotes/20.3.0.html
Article updated. That's nice to hear. Thanks!
paroj wrote:
Sat Feb 06, 2021 11:32 pm
actually, these are exactly the 2000-era PBuffers. There is even EGL_TEXTURE_TARGET to be used instead of a FBO.
While NVidia does not support this, I could make it work using MESA and use EGL/PBuffers instead of FBOs on the GL1 RenderSystem, which still has code for rendering that way.
Mmmm. It's one of the things where "you're right, yet...". It's a whole different mindset and philosophy.

The PBuffer support in 2000-era was competing against FBOs to get offscreen rendering as part of the regular rendering pipeline (e.g. to render into shadow maps).

While the PBuffer that EGL offers is more geared towards fully headless solutions.

Re: [News] Ogre 2.2.5 Cerberus Released and EGL Headless support!

Posted: Sun Feb 07, 2021 12:49 am
by paroj
dark_sylinc wrote:
Sun Feb 07, 2021 12:01 am
The PBuffer support in 2000-era was competing against FBOs to get offscreen rendering as part of the regular rendering pipeline (e.g. to render into shadow maps).
yes, thats what I made the GL1 RenderSystem do with EGL.

The PBuffers are the same, its EGL which is different. In contrast to GLX, EGL can run without an X server using a "default display" or a specific one which is associated with a particular GPU (the latter is an EGL extension though).
The PBuffer is just the missing bit to give it a in-memory surface to attach a context to - just as in the "old" days.

Re: [News] Ogre 2.2.5 Cerberus Released and EGL Headless support!

Posted: Sun Feb 07, 2021 2:44 am
by paroj
mmozeiko wrote:
Sat Feb 06, 2021 11:53 pm
This is not very accurate. For a few months mesa supports OpenGL 4.5 for llvmpipe software rasterizer. See the release notes for v20.3.0: https://docs.mesa3d.org/relnotes/20.3.0.html
they already claimed it for 20.2: https://docs.mesa3d.org/relnotes/20.2.0.html

but all I get here is OpenGL 3.1 - go figure..