So, I'm new to OpenGL... I have general knowledge of game programming but little practical experience.

I've been looking into various articles and books and trying to dive into OpenGL, but I've found the various versions and old vs new way of doing things confusing.

I guess my first questions is does anyone know some figures about percentages of gamers that can run each version of OpenGL. What's the market share like? 2.x, 3.x, 4.x...

I looked into the requirements for Half Life 2 since I know Valve updated it with OpenGL to run on Mac and I know they usually try to hit a very wide user-base, and they say a minimum of GeForce 8 Series. I looked at the 8800 GT on Nvidia's website and it listed support for OpenGL 2.1. Which, maybe I'm wrong, sounds ancient to me since there's already 4.x. I looked up a driver for 8800GT and it says it supports 4.2! A bit of a discrepancy there, lol.

I've also read things like XP only supports up to a certain version, or OS X only supports 3.2, or all kinds of other things. Overall, I'm just confused as to how much support there is for various versions and what version to learn/use.

I'm also looking for learning resources. My search results thus far have pointed me to the OpenGL SuperBible. The 4th edition has great reviews on Amazon, but it teaches 2.1. The 5th edition teaches 3.3 and there are a couple things in the reviews that mention the 4th edition is better and that the 5th edition doesn't properly teach the new features or something? Basically, even within learning material I'm seeing discrepancies and I just don't even know where to start.

From what I understand, 3.x started a whole new way of doing things and I've read from various articles and reviews that you want to "stay away from deprecated features like glBegin(), glEnd()" yet a lot of books and tutorials I've seen use that method. I've seen people saying that, basically, the new way of doing stuff is more complicated yet the old way is bad >.>

Just a side note, personally, I know I still have a lot to learn beforehand, but I'm interested in tessellation; so I guess that factors into it as well, because, as far as I understand that's only in 4.x?

[just btw, my desktop supports 4.2]