An update about geodesics

Hello again Stefano,

I took your advice about blogging about my progress, I have been posting
short form notes about my development here:

http://crystalspacegeodesicsphere.tumblr.com/

currently I have to fix a slight problem with warping, but I believe I have
solved it on paper so I will probably have that finished tomorrow. I also
have made several small design changes:

First, I have chosen to use a truncated Icosahedron, since it has exactly
12 pentagons and follows a very specific pattern of hexagons and pentagons
(all of the pentagons are located on the X, Y, and Z axes making it easy to
subdivide the sphere using the tiles). So the truncated Icosahedron lends
itself to being drawn modularly and can be done iteratively opposed to
recursively. This should make tracking texture and LOD issues easier to
handle.

Since all geodesics follow certain patterns (the algorithm is something I
have already worked out on paper) the design will have to be set up as a
structure with a discrete resolution, i.e. the number of tiles that make up
a sphere, while the cords and radius can have continuous sizes. Due to this
I think it would be best to have the function that generates the sphere
only allow for a discrete resolution (meaning only available as whole
numbers, I am working on a function that will generate the resolution on a
real number scale).

As for LOD control, the latest idea that I have been playing with in my
designs is a modular tile design, since the whole surface is already built
entirely of regular sized tiles, I think it would super intuitive to handle
all of the terrain mapping to each tile individually. This would be done by
using the crystalspace terrain generator to build 2 square height maps that
would represent each hemisphere. After a hemisphere has been generated the
program will then break the height map into hexagonal tiles which can be
mapped directly to the sphere. I like this idea mainly because if it is
possible none of the existing libraries will need to be changed since all
the work will be done in the planet simulation.

A big problem with this idea is that I am not sure how to handle the
pentagon tiles yet, however on the higher resolutions this is less of a
problem due to the fact that the number of pentagons is a constant 12.

Although another upside to the modular design is I can use it with
Christian's math (from your previous correspondence) to turn off tiles that
are not seen by the camera.

have a few questions however, to save time since I was unsuccessful last
week at securing the time to work on it so I have just started really
working on this about 3 days ago, so I would like to know which classes and
functions I would have to look over to get a good grasp on how your
renderer works. So if you could get me a list of the classes you think
would be the most beneficial for me to look over I would be very
appreciative. I should be on track to finish the basic soccer ball model by
saturday.

Does everything seem to be in order? Any suggestions?

Thanks again,

Benjamin

P.S.  didn't really proof read this e-mail so let me know if anything needs
verification

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