Help for OpenGL 4

[Stephane-M]

Hello,
my club is currently developing an opensource flight simulator in OpenGL 2 and C++.
http://fly.simvol.org/indexus.php

Given the number of graphic limitations of this version, the development team has decided to update progressively the project to allow it to run with the OpenGL 4 API.

Recently, the developers told me that given the lack of workforce, the upgrade to OpenGL 4 risks to take time.
My question is the following: is someone ready on this forum to help us, under any form, to convert this project in OpenGL 4 ?
Thank you.

[BionicBytes]

Why can't you complete the project using the compatability profile?
That way you don't have to recode existing functions and you can still use GL 4 funtionality. Also why GL 4 specifically? Tesselation a factor for you? It does rather limit your audience.

[dukey]

Opengl 4.0 seems like a fairly insane choice. You limit yourself to top end cards only. Even my nvidia 9800 card only supports opengl 3.0 ..

[Alfonse Reinheart]

You limit yourself to top end cards only.

You limit yourself to recent cards only. There are plenty of cheap graphics cards that support 4.0. You can get motherboard-embedded GPUs nowadays that support GL 4.0. AMD is already shipping AMD Fusion CPUs that have 4.0-capable GPUs.

That being said, there's not a huge difference between 3.x and 4.x, for most normal uses. The biggest obvious feature is tessellation, which might be of value in a flight simulator. The next biggest feature is shader_image_load_store, which has a variety of uses, but is really not for someone coming from 2.1 land.

Also, BionicBytes is correct in that you're limiting quite a bit of your audience. Using the Steam Hardware Survey as an example, the number of users with 4.0 capable hardware is much smaller than those with 3.3 capable hardware.

[dukey]

Intel has 50% of the market share, and they don't have any cards that support Opengl 3 yet ? We get a lot of customers with intel cards, and it's a headache for me because their drivers are so god damn buggy.

[malexander]

Now that Intel has released their Sandy Bridge Xeons with the new* P3000 professional graphics, perhaps they will put more effort into their OpenGL implementation.

Have you attempted to contact Intel about issues with their driver? We've had some success getting a few things fixed by raising issues with them.

* - not new hardware, just a different driver.[/B]

[dukey]

How does one complain about Intel drivers? The problems I had with intel were so bad that I had to code some pretty obscene work arounds just to be able to get usable output at all from their drivers.

Final output looked something like this on Intel
http://i126.photobucket.com/albums/p...uff/image1.png

Where as it should look something like
http://i126.photobucket.com/albums/p...uff/Image2.png

[malexander]

Yeah, that's not too far off some of the issues I've seen with trying to something moderately complex on Intel graphics. Complete freak out I usually have to kindly deny the Intel OpenGL driver entry to those codepaths and disable the associated feature(s).

Generally, reporting a driver issue involves simplifying the offending code until the problem area can be isolated. I usually strip everything out but the absolute basics and then gradually add them back in. It's pretty tedious.

Intel does have a forum for graphics software development:

http://software.intel.com/en-us/foru...sual-computing

You could try taking it up with them there. Sadly, drivers don't seem to get better on their own.

[Stephane-M]

We are not interested specifically in the 4.0 version as such. What we want is to use shaders rather than the fixed pipeline functionality, because we will be able to provide better graphic like per pixel lighing for instance.
So may be we can use shader from older version, but we think that OpenGL 4.0 will become rather commun in one or two years from now.

[malexander]

In that case, look into OpenGL 3.3. It's supported on all DirectX 10 capable hardware which has been around for about 6 years now (ATI HD 2000 series and up, Nvidia GEForce 8000 series and up). Once OpenGL 4 (DX11) hardware becomes more commonplace, you'll be able to add GL4 features to your GL3.3 engine without much trouble.

Besides tessellation, OpenGL 4.x gives you more flexibility when writing shaders (subroutines, sampler & uniform block array access). However, it's something that is easily worked around; I wouldn't restrict your audience just for those.