RE: [Algorithms] FPS Questions

[Bass, G. T. <gt...@ut...>]

Algorithms folks,

	I'm surprised no one has mentioned thus far the most significant
difference between movie frames and real-time gfx frames.  I know I drag you
all through this each time this discussion comes up, but I'll rehash once
more.

	If you look at a single frame from a movie, you will notice that
moving objects are blurred, since the film is exposed for a short period of
time and records light reflected from moving objects continuously during
that time.  This is the well known "motion blur", which, incidentally, looks
nothing at all like what 3dfx acheives with their T-buffer.  Motion blur has
the effect of connecting the multiple discrete images into a more complete
recreation of motion as the eye is sequentially exposed to each frame,
essentially creating a near overlap between each frame.

	Examination of a single frame rendered by a real-time gfx system
will show something quite different.  Objects in the single frame appear to
be totally static, and there is no hint of motion.  For this reason, higher
framerates become important as 3D objects move more quickly across the
screen, as these fast objects will appear more disconnected if allowed to
move very far (in screenspace) before they are rendered again.

	A good example of this would be roadside objects in a driving game.
As you pass lightpoles and other such goodies, they begin to cover
screenspace very quickly near the outside edges of the screen, and may even
appear to move backwards at certain speeds when the next object is closer to
the location of the previous object from one frame to the next.

Regards,
Garett Bass
gt...@ut...