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billb
Posts: 177
Joined: Wed Sep 19, 2012 10:27 pm

OpenGL limitations

Sun Sep 23, 2012 3:50 pm

Sorry if this is covered clearly somewhere in the FAQ, Wiki, or introductory guides, but I haven't been able to find much information.

Most of my experience with Linux has been on a system with no hardware accelerated OpenGL capability (Sony's now-deprecated OtherOS / PS3 Linux). Having seen videos of the RPi running Quake 3 I was hoping to finally be able to run some OpenGL / 3D applications and games without much trouble.

Having played around on Raspbian for a while It's now becoming obvious that it's not that simple. Games like "Brutal Chess" are not going to work "out of the box" at this point. Emulators such as Stella (Atari 2600) and VICE (Commodore PET/VIC20/C64/128) with OpenGL support won't allow you to enable OpenGL (at least not without modification?).

So I've read a little about OpenGL vs OpenGL ES and the RPi's implementation of X, but am hoping someone will come along and explain the current status, where things are headed, and so on ... also, if it isn't already, I believe this information should be clearly posted in the new user section and/or the wiki to help set expectations.

Will "normal" OpenGL support be coming at some point so we can run things like Stellarium, Brutal Chess, BilliardGL and whatnot from X or would all these types of applications need source code modifications to possibly work?

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: OpenGL limitations

Sun Sep 23, 2012 4:19 pm

No, there will be no OGL support - it will remain OGLES. ES stands for Embedded system, which is the market from where the SoC came, hence staying OGLES.

Stellarium has an OGLES option I believe.

It's not a huge leap from GL to GLES - the original Q3 demo was OGL and had to be converted. Not sure exactly what was done though.
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hellonearthis
Posts: 22
Joined: Sun Aug 05, 2012 6:35 pm

Re: OpenGL limitations

Mon Sep 24, 2012 8:04 am

That short hand made understanding that hard,
I guess OGLES = OpenGL ES as in http://www.khronos.org/api/opengles/2_X.

Just been looking at what I would need to do work in OpenGL ES on the Pi.
http://benosteen.wordpress.com/2012/04/ ... x-windows/
The Wiki over on http://elinux.org/RPi_VideoCore_APIs is getting better too.

reggie
Posts: 151
Joined: Fri Aug 26, 2011 11:51 am

Re: OpenGL limitations

Thu Sep 27, 2012 11:56 am

Stellarium just requires that Qt4 is compiled with GL ES extentions, then when you're compiling stellarium, it needs a switch to tell it to use GL ES too. I haven't done this yet but it should work reasonably well.

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billb
Posts: 177
Joined: Wed Sep 19, 2012 10:27 pm

Re: OpenGL limitations

Thu Sep 27, 2012 10:20 pm

reggie wrote:Stellarium just requires that Qt4 is compiled with GL ES extentions, then when you're compiling stellarium, it needs a switch to tell it to use GL ES too. I haven't done this yet but it should work reasonably well.
I did try building Stellarium with OpenGL ES enabled but ran into exactly the same problem mentioned here:

http://www.raspberrypi.org/phpBB3/viewt ... 86#p147486

I haven't attempted to build Qt4 with GL ES -- would like to see that provided in the Raspbian repository.

As mentioned in my first post, it would be nice to include some information in the FAQ / wiki / intro guides regarding OpenGL vs OpenGL ES and what to expect. There are quite a few OpenGL-only applications and games in the Raspbian repo which are going to run extremely slowly or not at all.

reggie
Posts: 151
Joined: Fri Aug 26, 2011 11:51 am

Re: OpenGL limitations

Fri Sep 28, 2012 12:34 pm

Perhaps we need to speak to some qt4 guys then?

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