Re: RE: 3D Follow Terrain =?iso-8859-1?Q?=BFdo?= I need gravity?

[Agust�n Mar�a Rodr�guez]

Thank you very much for your thoughts. They really help me a lot. I
can�t implement them right now in my project �cause I�m "upgrading" it
from globals to properties. All that discussion about how bad are
globals messed my mind and I decided to learn how OOP works. So I�m
starting again my project. Besides, all the demos and example have in
their code properies instead of globals...I think that�s for a reason.
Doesn�t?.

But I�ll let you know how my project goes as soon as I finish with this
properties stuff.
Thanks again.
Agust�n 

Thomas Higgins wrote:

> Agustin,
> Gravity of some sort is needed, but let's talk about how we implement that...
>
> What is desired? To hold the cylinder _down_ on the terrain of movement. Therefore 
>I'd suggest that you periodically (every exitFrame, prepareFrame or using a timeout 
>object) determine the model's position in the plane of movement (you cite "y" as up, 
>therefore the plane of movement is the x-z plane), then from the model's position 
>cast a ray downward (along -y in your case). This ray will intersect the terrain 
>below and the detailed information returned will allow you to get the distance 
>between the model and the point of intersection. If this distance is less than 
>desired, calculate the diff and raise the model (increase its y position by that diff 
>amount). If this distance is greater than desired, calculate the diff and lower the 
>model (decrease its y position by that diff amount).
>
> Does that help? I'm using this same technique in my terrain following demos for the 
>dummy box used to orient the biped character, but with a twist. I was concerned with 
>the character possibly moving so far between ray casting that it might actually drop 
>below my terrain (and thus a ray cast downward would *never* intersect the terrain). 
>Therefore I actually cast a ray from a point at some increased altitude position 
>directly above the model (I pick an altitude higher than my highest mountain top for 
>example). This prevents any problems if the character drops below the terrain. This 
>may or may not work for you being as you'll have a second floor somewhere above your 
>head leading to confusion.
>
> I hope my thoughts have helped, keep us posted on how things go!
>
> Rock on,
> Tom
>
> > -----Original Message-----
> > From: Agust�n Mar�a Rodr�guez [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, June 28, 2001 3:50 PM
> > To: [EMAIL PROTECTED]
> > Subject: <lingo-l> 3D Follow Terrain �do I need gravity?
> >
> >
> > Thanks Tom Higgins and Alex Smith for your help. It has been
> > very useful
> > to me.
> >
> > I would like to know how my cylinder (happy parent of my camera) can
> > follow a simply terrain. For example: to walk on a stair and
> > going from
> > the first floor to the second. Let�s do it without steps,
> > only climbing
> > a ramp.
> >
> > I imagine that I can tell the cylinder to increase the Y axis when it
> > collides with the ramp. Suposing that�s right, for going down I would
> > have to put an invisible ramp in the roof and decrease the Y axis?.
> >
> > These ideas are a little bit crazy, so I imagine that it has
> > to be some
> > gravity behaviour for going down like there is in the common 2D
> > sprites.  I�ve tried to figure this out alone studing the
> > terrain follow
> > and Island examples, but they are too difficult to me and I
> > don�t think
> > my simple stairs require all that code.
> >
> > I would aprreciate your help. Thanks again.
> >
> >
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>
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