plib-users

[Plib-users] Loading geometry information

[Ben W. <be...@ec...>]

Hello

Is it possible to send geometry information without using a model 
loader. I would like to send the model information across a network 
using worldforge. Also how do I setup a height field.

Thanks Ben

-- 
Programming law 1:
It's easy to make things complex but it's hard to make them simple.

Programming law 2:
In theory, theory and practice are the same.
In practice they're NOT!

Re: [Plib-users] Loading geometry information

[Wolfram K. <w_...@rz...>]

Ben Woodhead <be...@ec...> wrote:

>Hello
>
>Is it possible to send geometry information without using a model=20
>loader. I would like to send the model information across a network=20
>using worldforge.

You can create a ssgVertexArray and do a addKid.
I would suggest you start with a loader, either by tweaking the code
or by understand a loader and then coding what you need from scratch.
A simple one is ssgLoadTRI.

> Also how do I setup a height field.

You have the heights for a regular 2D grid? Then I would
"manually" create TriStrips or QuadStrips. Most things you know from
OpenGL may be used in PLIB.

>Thanks Ben

Bye bye,
Wolfram.

Re: [Plib-users] Loading geometry information

[Steve B. <sjb...@ai...>]

Ben Woodhead wrote:

> Is it possible to send geometry information without using a model
> loader.

You can *create* geometry without a loader - yes.

> I would like to send the model information across a network
> using worldforge.

I don't know much about worldforge.  Generally, to sent something
over a network, you have to convert it to a neutral format - and
probably the best way to do that would be to save it to disk and
transmit the file across the net...but it depends a LOT on how
much generality you need and the volume and speed of data you expect
to send.

> Also how do I setup a height field.
 
You could check the example program:

    examples/src/ssg/majik

...that creates a polygonal skin from a regular height field.

----------------------------- Steve Baker -------------------------------
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Re: [Plib-users] Loading geometry information

[Sam S. <sa...@sp...>]

----- Original Message -----
From: "Steve Baker" <sjb...@ai...>
To: <pli...@li...>
Sent: Sunday, June 10, 2001 11:44 AM
Subject: Re: [Plib-users] Loading geometry information


> Ben Woodhead wrote:
>
> > Is it possible to send geometry information without using a model
> > loader.
>
> You can *create* geometry without a loader - yes.
>
> > I would like to send the model information across a network
> > using worldforge.
>
> I don't know much about worldforge.  Generally, to sent something
> over a network, you have to convert it to a neutral format - and
> probably the best way to do that would be to save it to disk and
> transmit the file across the net...but it depends a LOT on how
> much generality you need and the volume and speed of data you expect
> to send.

Hmmm.. I saw a library on sorceforge that could send model information over
a network - I think it had it's own (basic) scenegraph library as well.  If
I remember correctly it could do model deformation as well. I'll see if I
can dig out the homepage for ya.

But, aside from using that library, it quite a task to do.  If I were you
I'd do like Steve suggests pick a compact (or easily compressable)
file-format - perhaps write your own ssg exporter.  You can send this file
to the clients along with a GUID of some type to reference it.

What you do also depends if you intend on sending models only when a client
connects, or if you want to be sending them at other times as well (ie.
during gameplay). (If it's the later you'll need some way - or WorldForge
will - to prioritze data streams so you don't flood connections).

If you are also using a LOD system for your models (with seperate meshes),
you can send the low-detail ones first so the client should always have
something to display.  For a worst case situation keep the most basic meshes
very very simple (ie. a rectangle, or a sphere - use ssgAux's shapes to
describe them and you can keep the file sizes down a lot).

But if you want to do more complex stuff (deformation of vertex meshes
etc.), then it's a LOT more work.

Sam