[Plib-users] How should I use plib?

[Troy Y. <tro...@ho...>]

Sorry for the long post.  I'll ask my question(s)
up front.  A description of what I've been up to follows.

Q: What is the best way to create a scene/world using plib?
   It seems to me that loaders are extremely useful but
   what is their impact on one's ability to render a scene
   quickly and efficiently?  Aside from loading a model,
   and scaling/rotating/translating it what else must be
   done to manage the scene/world (i.e. BSP trees, LOD, etc.)?


What I'm doing...

The project I'm working on (day job) is a naval simulator
in which ships, aircraft, subs, weapons, rain clouds,
countermeasures, and biologics (whales, birds, etc.) appear.
A game engine exists that moves things around periodically.

Currently the only view into the simulation is a via
a 2D birds-eye representation using standard symbology.
I'm interested in spicing things up with a 3D representation.

Enter OpenGl... Enter plib...

Using the Tux-on-a-box example as a starting point, I've
managed to put something together that places models at the
correct locations and even has an ocean and land... first
iteration complete!

Now it's time to refine/improve/tune through reiteration
- and there's lots to do here.  

My current method of populating the scene is not at all
practical (not to mention ugly) especially with regard to
land and ocean.  Right now, I'm using an AC3D model of a
plane composed of 4 co-planar quads and scaling that to my
game boundaries (2000 nautical miles on a side).  I know I
could get creative and draw only a large enough 'ocean' to
produce a rendered scene that looks right but I've been
working in'minimum intervention' mode - aside from pointing
the camera, I don't have to do anything once the models are
placed. (Please remember that this is my first iteration on
my first OpenGl/3D program! :)

One of the immediate problems with my ocean approach is that
the ocean often disappears - it depends on the direction the
camera is pointing and where in the scene it is placed.  I'm
guessing that it's getting culled because there are no vertices
of the ocean inside the view frustum. Ok, so I'll have to use a
different method.  Eventually I'll want to add a texture and
possibly even some height variations (waves).  Before I talk
about this further, let me tell you about land.

I mentioned above that the game area is quite large - 2000
nautical miles on a side.  Although all action will typically
take place in a very small portion of the map, there is no
way to decide up front where that might be.  It is also
possible to 'warp' any entity to any place on the map at any
time. Since this is a naval simulation, most of the action
will take place on the water but may be near a major land mass.

At the moment, my land resolution is very coarse - altitude
in feet at every nautical mile grid point
(= 2000x2000 = 4,000,000 points).  Since much of this will
be water in many instances, I'm not using a 2000x2000 array
to store the data.  

Here's the worst part (I think) of how I'm realizing this land
in the scene... <cringing in anticipation of being bashed about
the head>... I'm loading a single instance of a unit sized AC3D
cube, scaling the height to match the height of a grid point
(by adding model to ssgTransform node) and translating it to
the appropriate grid location.  The net result is lots of
stretched cubes clustered about.

I know this is not going to work (it's not scalable and it's
UGLY) but I wanted to put something together with minimum
effort on my part (Think 'baby steps!').  I noted that
FlightGear has defined a bunch of tiles that get loaded
in and I assume that something like this is the way to go
here. How does one deal with being able to warp the
camera anywhere on the map though?

Well, thanks for your time.  Any pointers/comments would
be appreciated - perhaps you know of a 'getting started'
tutorial?  Anyway, welcome to my adventure! :)

Troy.