OK, just skimmed the OpenGL 4 spec and it is hardly a joke. Bur there are some problems that still remain with the original article, and the benchmarks that compare the Windows and Linux versions of Steam.
- The comparison was made with DirectX 9 (eight years old) and OpenGL 4 (fairly recent), rather than an optimised DirectX 11.Notice that when they used the optimised OpenGL on Windows XP (an old OS), the frame rates were dead even.
- The specs on the machines for the benchmark are hardly that of the average Steam user, according to Valve's own user surveys. They used a high end gaming box, the average user has a dual core with integrated Intel graphics
- OpenGL uses a call to OpenCL (the 'glCreateShader()' function) to use Compute Shaders. It does this this very cleverly without having to load libraries, but if I'm not careful I can still get a scheduling stall. With DirectX, the Compute Shader is a part of DirectX itself, so I needn't worry about scheduling issues and resources.
And lastly, there is something else that really gets to me. See, we can talk about APIs and GPUs and what not, but at the end of the day, the only thing that matters to these people is ROI - Return on Investment. That is why OSS has not had major support from mainstream game studios, or why we have not had the Great Open Source Videogame? Why would I want to make a video game for a small segment of techies, who are philosophically opposed to paying for software?
Well, if you are a game studio with an App Store , who has just had their app banned from a major competitors App Store (as Microsoft has done to them in Windows 8), and cannot turn to , say Apple, you may to play Knight in Shining Armour to the Open Source crowd. Never mind that Steam is one of the most heavily DRMed software ever released, you know that the penguinistas and the tech media will do anything to get one in on Microsoft. Free advertising and support, without having to spend a single cent. Know that;s what I call Return on Investment.