Re: [stella] which way to turn?

Subject: Re: [stella] which way to turn?
From: Kirk Israel <kirkjerk@xxxxxxxxx>
Date: Mon, 25 Jul 2005 13:58:43 -0400
Hmm...actually I haven't tried to hard but it was tough finding a good
online description of how to calculate a cross product, and then
multiply it...

On 7/22/05, Aaron <stella-receiver@xxxxxxxxxxxxxxxxx> wrote:
> Kirk Israel said:
> > So I'm trying to get something a bit like combat biplanes.  And I've
> > been musing on this problem: how would I get, say, an onscreen heat
> > seeking missile to work?
> >
> > Basically, it has to know if it should turn left or right to get to the
> > target.
> Hey, I have something useful to say for once! :)
> Take the missile velocity, that's one vector.  Then take the distance from
> the missile to its target, that's another vector.  Take their cross
> product, i.e. y1*x2 - y2*x1.  If it's negative, you turn one way, if it's
> positive you turn the other (I forget which is which, but it should be
> easy to figure out).  I did this in a Palm game once and it looks cool...
> -Aaron
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