Angus Dorbie (dorbie++at++sgi.com)
Mon, 06 Apr 1998 11:42:39 -0700
This is because they don't move their eye w.r.t. the display surface.
The FOV in a simulator should be determined by the display and the
position of the eye w.r.t. that display. So sit in the design eyepoint
with a protractor and measure the angle of the fullk screen horizontally
and vertically. That's the horizontal and vertical FOV you need.
Anything
else either too narrow or too wide will distorted.
The wider the FOV the poorer the resolution in the center of the
channel because your eye is basically too close to the screen.
>
> (NOTE: I'm talking angle-subtended-by-screen-at-eyepoint here -
> some people talk "half-angles" - make sure you know which you are
> talking about)
>
> * If you are projecting onto a FLAT screen then there is no distortion
> in the image for any field of view up to some point just under 180
> degrees. At or beyond 180 degrees everything screws up big time!
>
> The Z buffer precision for objects at the edges of very wide angle
> displays becomes a bit of a problem - and the kludgy way that
> fog is implemented is certainly a problem with wide FOV.
I disagree with the zbuffer part, in fact I'd say precision _better_ by
range at the sides because you have nearer z for equivalent range. The
penalty is ofcourse the clip is in z not range but this is trivial. Fog
is a problem because it's z fog and not range fog so I agree with you
there.
Cheers,Angus.
-- "Only the mediocre are always at their best." -- Jean GiraudouxFor advanced 3D graphics Performer + OpenGL based examples and tutors: http://www.dorbie.com/ ===================================List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/ Submissions: info-performer++at++sgi.com Admin. requests: info-performer-request++at++sgi.com
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