On Windows, how does OpenGL differ from DirectX?

Question

I don\'t have any hands on experience with graphics programming. I got this doubt when I was reading about graphics programming.

From what I understand, because Wind

Answer 1

No, both languages talk directly to the graphics card hardware through a driver written by the card manufacturer so both offer the same level of hardware access.

Windows support DirectX directly, it's part of the OS needed for pretty display effects - their support of OpenGL is rather more limited, they only support v1.1 (we are now on version 4) so to do anything useful you need to use some extra extentions (such as glew) or the graphics card makers OpenGL SDK.

In terms of capabilities. DirectX is carefully controlled by MSFT - so all DirectX systems should behave identically. OpenGL allows graphics card makers to add their own extentions, so they can produce higher performance by adding specific features to the hardware (at least in theory). OpenGL is also cross platform, so your Windows OpenGL code will run anywhere (in theory)

In practice the only OpenGL drivers on Windows that aren't completely useless are NVidia - so high performance OpenGl apps on windows pretty much require an NVidia card. This means that it's easy to program OpenGL on Windows - you just stick to NVidias docs.