For the first arguement in gluPerspective what could be considered a default or natural
field of view, 45 degrees, 55, 110, for a human that is!.thanks.
The human eye has a total field of view of slightly less than 180 degree. However, you can not distinguish anything usefull, except movements, in the peripherical areas. A ‘normal’ field of view for a standard application should be around 60 degrees. But if you want ‘exact’ proportions, you should measure the angle between the vectors nosetip_to_leftsideofwindow and nosetip_to_rightsideofwindow, and use that as horizontal field of view. But I suggest something around 60-90 degrees, which usually end up with good perspective feelings.
[This message has been edited by Bob (edited 12-05-2000).]
90 degrees!?!? That isn’t very natural at all! I agree 60 is pretty good, but 90 is pretty out there!
Well, tried to give some general directions. 60 is good in most cases. Slightly lower angle might be ok aswell, but it’s getting a tad too narrow below 50. And OK, i can agree that 90 can look a little wide sometimes. But it depends on what you want. With a large window, and if you wans a slightly wide scene (not so wide that it starts looking bad), you end up close to 90 degrees.
Best is probably to make the fov variable while running and test for the best value/result.
Oh, another question. Is it anyhow possible that object which are at an edge of the fov aren’t differently fogged than objects in the center?
Heh, 60 degrees is trim. I play Quake3 at 120 deg. FOV. 
Makes me feel like an Alien. But, afa OGL proggies, I’d suggest 60 to 90.
Just my 2 cents…
Glossifah
The problem I see with using large fov’s like 90 is that when you turn, things to the side look ALOT bigger than when they’re in front of you which, to me, looks VERY unnatural. Or, as it has been put before, alien.
The alien feeling is because the actual radial distance to the verices is not used. It’s like the standard fogging system, it’s the projected Z-distance that matters. And as the fov is getting larger, the error is getting larger. And at 90 degrees, it can start behaving too strange. Below, it’s not that noticable, unless you know what it will look like. But as it had been said already, 60 is a good and common choise.
And to you Michael: Use the extension called NV_fog_distance . It lets you use radial fog instead of the usual Z-distance fog.