Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: shade@dragonshadow.com (Scott Cartier)
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: What do'you mean I have to brush up on me maths!
Date: Wed, 14 Jul 1999 20:56:30 GMT
Organization: SCEA News Server
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>Surely there's a maximum amount that can be entered, as the input is
>calculated from the position of a player, which is probably on the screen.
>You could probably work out the maximum input for the inverse tan, by taking
>the largest point on the screen, and using it in the calculation for the
>input. However, you'd have to be certain that the maximum screen
>width/height will be the maximum of values used in the input.

As "dx" approaches zero (which means the velocity vector approaches
straight up or down - not at all unreasonable) the division result of
(dy / dx) blows up.  Plus, if dx is EQUAL to zero then you have that
dreaded divided-by-zero error.  You could special case that away
though.

Yeah, I guess if you're not going for high precision you could make a
look-up table.  But without high precision you're more at risk for
rounding errors which could make things look bad.

Scott