Important info for Terrain Rendering demos

Unlike most of the other examples, before you can run this code, you will
need to do some preparation work.

The terrain rendering code loads raw data from various file formats. In the
current code, that is the BT file format from the VTerrain Project
(http://www.vterrain.org). These are *big* files when uncompressed, so we
keep them as compressed data in the repository. You will need to uncompress
them before running the demo program, otherwise the demo will crash. When
you uncompress them (in GZip format) leave them in this directory and run
the application from this directory.

The Crater example does not have a texture, so all you will see is a green-ish
colour terrain. The alien surface does have a texture, but it is also twice
the size of the crater example. At least on my standard setup here, it creates
out of memory errors. That's not good and I'm working on doing some
optimisations to prevent this. However, if you have a lot of memory to play
with, try setting the minimum JVM heap size to 128MB and running it. Let me
know if it works, because my laptop I'm developing this on croaks at having
so much memory in use :(

There's a bug in the code currently that prevents the top-down view on the
right showing anything. I'm not sure what it is yet, but probably has
something to do with the height not being set correctly and the viewpoint is
"under" the terrain so there is nothing to see. Will look into that further.

The TiledCullingDemo will require a JVM with 256M of memory so use the -Xmx256M
option to run that demo.  The numgrid.jpg.gz will need to be uncompressed
before running.

Justin Couch, Alan Hudson
Oct '02