So far most AAA games are still developed for DirectX only. Those are the games that make or break a platform. Doom 95 was arguably the kind of killer app that established Windows as the primary gaming OS. In the context of Valve's SteamOS strategy it makes perfect sense to encourage more major developers to build games on a portable API like OpenGL or possibly AMD's Mantle by making it as easy as possible. If they fail at this, SteamOS, Steam Boxes and gaming on Linux in general won't have a chance at mainstream success.
sorry if i wasn't clear, but i am aware that most AAA games use DX. the same is not true for open source.
there are already DX->GL compatibility layers, although most of them are in house, by companies that produce ports (ala Feral Games).
yes, i entirely agree with you.. almost. ideally, i'd like DirectX to.. go away, forever. proprietary APIs that result in lock in to a software or hardware platform are seriously holding back computing in general. and i'd never recommend anyone use AMD's Mantle for the same reason (which is a massive waste of everyone's time)
Well there are possibly smaller studios and devs who perhaps don't have the resources to roll their own translation layers, for whom this might be a tipping point towards supporting SteamOS and/or Linux.
Since Valve has already written this for their own purposes, it'll cost next to nothing for this to be published if they can stop people expecting support, and they might get a few bug reports into the bargain.
> there are already DX->GL compatibility layers, although most of them are in house, by companies that produce ports (ala Feral Games).
And this is Valve releasing their particular variant mostly targeted at other major game studios. There is no reason every studio should be forced to create their own in house compatibility layer.
