[gameprogrammer] Re: argh, math!

I dont know if this helps any, but i might be going about this the wrong
way.

Im making a portal engine and what i need to be able to do is be able to
tell if a portal intersects with the frustum.

i have the 6 planes of the frustum, and i have the 8 points of the portal
(as well as the 6 planes of the portal). and need to be able to tell if the
portal and the frustum overlap.

is there a better way to do that maybe?

----- Original Message ----- 
From: "Kevin Jenkins" <gameprogrammer@xxxxxxxxxx>
To: <gameprogrammer@xxxxxxxxxxxxx>
Sent: Saturday, May 29, 2004 1:11 PM
Subject: [gameprogrammer] Re: argh, math!


> If I remember my linear algebra right, you have to put all 12 equations in
a
> matrix and do row reduction until you get a single 1 in each row.  Or
> something like that :(
>
> ----- Original Message -----
> From: "Alan Wolfe" <atrix2@xxxxxxx>
> To: <gameprogrammer@xxxxxxxxxxxxx>
> Sent: Saturday, May 29, 2004 1:14 PM
> Subject: [gameprogrammer] Re: argh, math!
>
>
> > Hey Rob,
> >
> > it sounds easy but nobody seems to be able to help :P
> >
> > lets say you have 12 of these:
> >
> > Ax+By+Cz+D > 0
> >
> > where in each of the 12 equations, there is a different value for A,B,C
> and
> > D.
> >
> > how could you be able to tell if there is some value for x,y,z that
> > satisfies all 12 equations?
> >
> > ----- Original Message -----
> > From: "Rob Quill" <rjquill@xxxxxxxxxx>
> > To: <gameprogrammer@xxxxxxxxxxxxx>
> > Sent: Saturday, May 29, 2004 1:01 PM
> > Subject: [gameprogrammer] Re: argh, math!
> >
> >
> > > OK, my maths isn't great, but they will be overlapping if the lines
> > > intersect, so by putting two of the equations equal to each other and
> > > solving you can see if there is a point of intersection.
> > >
> > > That sounds a bit too simple, so maybe I have mis-interpretted the
> > problem.
> > >
> > > Or thinking about it, could you not use vectors? If you had the vector
> > > equations you could use:
> > >
> > > a.b = |a||b|cos(x)
> > >
> > > But again, it seems too simple. Is it that hard to solve a equation 12
> > > times.
> > >
> > > Rob
> > >
> > > Rob
> > > ----- Original Message -----
> > > From: "Alan Wolfe" <atrix2@xxxxxxx>
> > > To: <gameprogrammer@xxxxxxxxxxxxx>
> > > Sent: Saturday, May 29, 2004 8:52 PM
> > > Subject: [gameprogrammer] argh, math!
> > >
> > >
> > > > hey everyone
> > > > I have a math problem im trying to solve for my game and am having
> > > difficulty :P
> > > >
> > > > i have a "box" defined by 6 planes in the form of: Ax+By+Cz+D=0,
where
> > > A,B,C and D are known constants for each equation.
> > > >
> > > > the box doesnt have to have corners at right angles, but it's
assumed
> to
> > > be concave.
> > > >
> > > > what im trying to do is take 2 of these "boxes" and see if they
> overlap
> > at
> > > all.
> > > >
> > > > so basicly from what i can tell i have 12 plane equations and what i
> am
> > > trying to do is find if there are any sets of X,Y,Z which satisfy all
12
> > > equations.
> > > >
> > > > I asked around how to solve systems of inequalities but people keep
> > saying
> > > "graph it", which doesnt help me any :P
> > > >
> > > > Does anyone know how to do this? I'm starting to think that there is
> no
> > > solution ::cry:: hehe
> > > >
> > > >
> > > >
> > > > ---------------------
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> > > >
> > > >
> > >
> > >
> > >
> > >
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> > >
> >
> >
> >
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> >
> >
> >
>
>
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