Valve Publically Releases "ToGL" Direct3D-to-OpenGL Shim
 

Though firmly rooted in the Microsoft technology camp for much of their history, in the past few years Valve has been expanding their reach to additional platforms and technologies. This started with porting their own games to OpenGL based OSes – first Mac OS X and later Linux – and of course more recently their efforts in rolling their own Linux distro with SteamOS. Throughout all of these processes Valve has been relatively open about what they’re doing and how they’re doing it, and this week they’re getting a bit more open on the API side.

Posted this week to GitHub, Valve has released the source code behind their “ToGL” shim to the public. ToGL is the translation layer Valve uses to bring OpenGL support to their games, essentially emulating a limited subset of the Direct3D 9.0c API and translating those calls to OpenGL. It is implemented within the game binary itself (this isn't an external wrapper), so this is primarily a tool for game developers. And although not particularly common, translation layers such as ToGL and even bigger full-on wrappers are often used to bring big budget multiplatform games to OpenGL platforms, as the PC ports of many games are still primarily coded against Direct3D and native OpenGL renders are sparse.

http://www.anandtech.com/show/7856/v...to-opengl-shim