OpenGL, even though somewhat behind DirectX, is usually faster than DirectX.

@ThomasB, considering its missing most of the features that DirectX has (geometry shaders, for example), doing those tasks would be significantly slower in pure software mode than hardware accelerated DirectX.

Also, please, show us some benchmarks that somehow illustrate a feature to feature comparison of DirectX to OpenGL on the same hardware, same operating system and same 3d software.

Maybe you can compare feature to feature Direct3D with OpenGL. But there’s nothing like DirectX anywhere in the industry, and that’s why so many use it.

Here’s a reason to use openGL: If you want people who use all three major os’s, Mac, Windows, and Linux, to be able to play your game or whatever.

Oh wow.

“OpenGL has faster draw calls”
Correct, but the difference is only noticeable on models and environments that consist of ridiculously high amounts of polygons. Your average gamer would never notice it.

“OpenGL has supported Tesselation for three years”
Double edged sword here. One, OpenGL is sloooow at tesselation. Secondly, it was only available because modelers (or for that instance, Autocad) wanted tesselation for these vast environments. Again, your average gamer didn’t know and didn’t care.

“OpenGL is cross platform, and supports PS3, Linux, Mac, Wii, and (of course) Windows”
Right, but your target audience is playing their Xbox360 right now. Supporting DirectX is a much more feasable solution provided that the Wii cannot handle intense graphics, Mac’s are NOT built to be gaming machines, and nobody uses Linux. Why use some slow technology that takes longer to use when you can knock out 90% of the market in one fell swoop. Not to mention you saved yourself hours of support.

Meant Audodesk, not Autocad.

Second correction, PS3 has OpenGL, but it’s slower than dirt. Wii has a wrapper for OpenGL (NOT ACTUAL OPENGL), and it is also slower than dirt. You’ll be using the native toolkits for these.

OpenGL only has a real use for movies, modelers, and high end renderers, besides Linux and Mac support of course.