it’s used wherever it is found to be useful. Primarily 3D games, apps, CAD, visualizations etc. (some of those, mostly games, use other APIs, like Direct3D on Windows or priopretary APIs on consoles).
“in” OpenGL or “with” OpenGL or “use OpenGL”? I guess some of better known ones are id software…
availability of the jobs for the smart persons: 10/10. Just knowing OpenGL won’t get you job (just like knowing any other API). API is just a tool to get something done, it is tiny, tiny fraction of what you’d actually need to know to get a job.
Andy, as someone said “knowing one API is knowing them all”. As every graphics API ultimatively uses the same ideas, being a good 3D programmer would mean the ability to quickly learn and utilize any 3D API. So you should concentrate on learning 3D graphics programming instead of “learning OpenGL” — it is just a tool, after all.
When I attended UCSD, many moons ago, I was shocked to find that the Chemistry department almost considered their class on OpenGL a requirement. Since then, I have been employed in a video conference company because I knew OpenGL. OpenGL has become a standard for graphics APIs in not only computers, but cell phones and other embedded programming environments. I don’t want to overstep bounds here, since I haven’t actually seen any game console APIs, but I wouldn’t be surprised if the only game console that didn’t use OpenGL was Microsoft’s.
If you are looking to learn a graphics API, be it 2d or 3d, I suggest learning OpenGL.
AFAIK, none of consoles use OpenGL (some use something similar, but not quite, to OpenGL ES). None of phones use OpenGL either (again, some use OpenGL ES).
Knowing API is nothing. You just have to know the principles hows things work (including how hardware works). Using one or another API is just a tool to put those principles to work, it can be learnt in a matter of days (ok, I am exaggerating here, but using the same principles on a different API is very easy).