[fixermark]

But as the original article notes (in a bit of a roundabout way), OpenGL-the-standard vs. OpenGL-the-ecosystem is a bit of an empty debate. Unless you're one of the privileged few who only writes OpenGL code that targets one hardware platform... It doesn't much matter what the standard says if my customers don't install hardware that can take advantage of the new standardized features, if they never upgrade their graphics drivers for their older hardware, if the driver vendors never bother to update the old drivers to meet newer versions of the standard that their hardware could support but is no longer in their financial interests to support, etc., etc., etc.

"OpenGL is broken" refers to the market adoption of the standard, because when you're developing graphics software for consumers that's the aspect you care about.

[fzltrp]

> "OpenGL is broken" refers to the market adoption of the standard, because when you're developing graphics software for consumers that's the aspect you care about.

(This isn't the only point the OP is arguing about, but anyway.) What exactly would be the alternative? It's either there's a standard, and adherents must follow its core features to get the compliancy stamp, or there are no standards, and each go its merry way, up to third parties to follow up on all the completely different API resulting from that. As someone else said, there are core levels in the standard, which give garantees to third parties. It hasn't always been like that, but now we do have them.

As for support of the latest features on my old Geforce 7600, I guess I should accept the fact that they cannot be implemented efficiently, and if I want to play the latest installment of Wolfenstein, I'll have to grab a new card. Or I could try getting a more modest game. There is clearly a commercial aspect to this whole upgrade mechanism too, but since upgrades are necessary for technical reasons, it's difficult to argue against the mercantile part.

[fixermark]

> It's either there's a standard... or there are no standards, and each go its merry way

In my experience, OpenGL walks the middle line. There is certainly a core set of functions that (almost always, discounting buggy drivers) work. But the core set doesn't span all the critical functions you need for what modern game players would consider a performant game engine (such as hardware synchronization to eliminate "tearing"). So game engines will need to factor in the GL extensions, which put us in the "up to third parties to follow up" world. It's a frustrating environment to work in; you can't really ever trust that your code will either succeed or fail on any given hardware configuration, and you're stuck playing whack-a-mole on bug reports that you lack the hardware to reproduce.

> As for support of the latest features on my old Geforce 7600, I guess I should accept the fact that they cannot be implemented efficiently

I wish it were that simple. That, I could deal with.

I've worked with a card that had a bug in the GLSL compiler. A particular sum simply wasn't compiled, and we had to work around the problem by multiplying by 1.000000000000000001 to force the compiler to generate the bytecode for the whole calculation (the fact this trick works is something one of our veteran engineers "just knew would work," so we got lucky). There is functionally no chance of that software bug ever getting patched; card vendors don't care about older versions of their technology, and even if a driver version were out there that patched the bug, you can't trust machine owners to keep their drivers up-to-date.

More frustratingly, as I mentioned elsewhere, I've worked with cards that implement things that should be high-performance (like stages of the shader pipeline) in software, just to claim they have the capability. Since OpenGL gives you no way in the API to query whether a feature is implemented in a reasonably-performant way, you either do some clever tricks to suss this stuff out (F.E.A.R. has a test mode where it runs a camera through a scene in the game and quietly tunes graphics pipeline features based upon actual framerate) or gather bug reports, blacklist certain card configurations, and keep going.

Old cards not being as powerful as good cards I can deal with; if we could simply say "Your card must be X or better to play," we'd be fine. New cards with bugs and under-performant cards that lie about their performance to clear some market hurdles are the maddening corners of the ecosystem.

[fzltrp]

> There is functionally no chance of that software bug ever getting patched; card vendors don't care about older versions of their technology,

Well, is that an OpenGL issue? Wouldn't you get that very same problem with D3D?

> reasonably-performant way

I don't understand. How can you objectively define such thing? Doesn't it depend on the workload? If you're pushing 3 tris per frame, any feature can be labeled as reasonably performing, but if you have 300M, can any card these days maintain reasonable framerate even on the most basic settings? I am exagerating on purpose; some apps will require a very small amount of work on each stage of rendering, and could reasonably afford any extra pass, even if software implemented. And in other cases (which might be the majority), it doesn't cut work. I don't see how there could be an objective way of deciding if a feature is sufficiently performant. Your example is telling: an application as complex as F.E.A.R. Should clearly make its benchmarks (or keep a database) to decide which feature can be included without hurting performances. And even then, players have also different perceptions of what constitutes playability.

I agree with you: multiple standards, multiple vendors, multiple products, the fallout is "struggling compatibilities" at worst, "varying performances" at best. But that's a common point between D3D and OpenGL, not a divergence. Am I missing something?

[Tmmrn]

> There is functionally no chance of that software bug ever getting patched; card vendors don't care about older versions of their technology,

Isn't it interesting that not more developers are pushing for open source drivers? Try finding a GLSL compiler bug in mesa and asking in #dri-devel on freenode or bugs.freedesktop.org. There you most likely get a very quick and helpful reply.