Path: chuka.playstation.co.uk!news
From: "John \( QuietBloke \)" <quietbloke@btinternet.com>
Newsgroups: scee.yaroze.freetalk.english
Subject: Re: Daft Question [long]
Date: Sun, 26 Aug 2001 00:26:30 +0100
Organization: PlayStation Net Yaroze (SCEE)
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Good point.. in fact the pause would probably make for a more realistic
response.

btw.. all that stuff I wrote about shifting etc.. it really was twaddle.. I
had a bit more of a think about other solutions and I have a nice simple
elegent one which should still be pretty quick... quicker then all them if's
and shifts and stuff !
Havent written it yet ( Ive been mucking around with the crap graphics
again.. trying to make them look reasonable ) but it goes something like
this.

I keep the table just as you got it but in the function : long
getAngleForXY(int dx, int dy, long currentAngle)



int tmpx, tmpy, tmp
tmpx = abs(dx);
tmpy = abs(dy);
tmp = (tmpx<tmpy) ? tmpy : tmpx;

if ( tmp > XYRange )
{
    tmp = ( tmp + XYRange -1 ) / XYRange;
    dx = dx / tmp;
    dy = dy / tmp;
}

return angleForXY[dy+XYRange][dx+XYRange];
}

So : for example if XYRange = 16 and dx = -17 and dy = 4
then
tmp = ( 17 + 16 - 1) / 16 which is 2
therefore
dx = -17/2 = -8
dx = 4/2 = 2

voila... the function will work.. OK.. so it doesnt end up with a brilliant
position in the table but its quick. The worst case would be this particular
one where I end up in the middle of the table. Im gonna have to try it to
make sure it doesnt end up giving me wobbly results but increasing the table
size should reduce it.

Dunno if this is of interest to anyone but what the heck.. Im sitting taking
a break from drawing so I thought Id share my thoughts.

Cheers
John ( QuietBloke )

"pal" <pal_news@hotmail.com> wrote in message
news:01c12ceb$fba64880$9709e4d5@pal-s-omnibook...
> John ( QuietBloke ) <quietbloke@btinternet.com> wrote in article
> <9m1d9c$b2i7@www.netyaroze-europe.com>...
> <snip> The only change I am going to have to do is that as I am
> > trying to find the angle between a bug and its target ( whatever it may
> be )
> > the distance may be quite large..
>
> Oh, yes, I had'nt thought about that. I just needed the angle to properly
> rotate a ship according to its deplacement. This will make a difference...
>
> ><snip>and I end up with 30-40 bugs calculating new directions each frame.
>
> What about not calculating every frame? A bug changing direction only once
> in ten or whatever frames should'nt make a visible difference; this makes
> for a cheap and big processor time saving.
>
> No other suggestions for now...
>
> pal
>