View Full Version : gluPerspective and fov question

12-04-2004, 12:06 PM
Hi there.

We generaly use 45 deg as a yFov in gluPerspective... But in real our yFov is 90, right? But when we put in gluP... 90 it cause big distortion. So whats up with it. Or am I getting sumthin' wron'???

12-04-2004, 01:35 PM
If you want a view without perspective distortion, you should calculate the angle between the top of the window, your face, and the bottom of the window. Typical vertical FOV for a fullscreen window then usually ends up at about 25 degrees.

12-11-2004, 06:28 AM
Well, I mean we can select in console or options fov to 90 and then it looks like we set 45 in gluPerspective. So my question is - does 90 from options correspond to 45 in gluPerspective?

12-11-2004, 04:07 PM
What "option" and "console" are you talking about? The angle you pass to gluPerspective is the angle between the bottom and top clip plane. 45 mean 45 degrees between the bottom and top clip planes, and that is a 45 degree vertical field of view.

12-12-2004, 02:52 AM
Right, I forgot something. I mean options or console in games - Quake, Unreal - 90 degrees is default value fov fov there. And it looks exactly like gluPerspective with 45 angle...

12-12-2004, 08:21 AM
In most apps and games, the FOV is the horizontal angle, whereas in Glut it is the vertical angle.
So you need some simple math to convert from h to v conversion.

12-12-2004, 11:47 AM
Anyway... If we assume that standard screen ratio is ~1,3 we have 68 degs in y. And that value in gluPerspective casues distortions, right???