Archived

This topic is now archived and is closed to further replies.

Switching from 3D Globe model to terrain engine?

This topic is 5003 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello, I''m trying to develop a 3D globe representation of the earth, with satellites orbiting around the earth, etc. I would like to be able to fly up close to the planet, but currently when I do so the earth does not look "earth-like" in size, and the quality becomes very low (I''m using a .3ds model of a sphere with a globe image mapped around it). Two questions: 1) When I get close to the earth, do I need to adjust my FOV/perspective somehow to make my globe model seem huge? 2) How can I get down to the surface of the planet and not lose quality? Do I need to switch to a terrain engine? How do I get my terrain engine to match up with the actual earth surface? Thanks--any book recommendations or links to info would be appreciated as well.

Share this post


Link to post
Share on other sites
You''re actually looking at a very complex problem. What you need is some data set that is infinitely scaleable. A simple textured mesh quite simply will not cut it. There just isn''t nearly enough information in a simple texture map, and to store all of the texture information necessary to construct an entire planet would require a database larger than any simple home computer can store and manage. Your only choice, then, is random generation of the planet and it''s features.

I suggest you look into fractal generation of planets or worlds to get some ideas on how this is accomplished. If you have ever played with fractals, you know that they can be zoomed in or magnified, pretty much to infinity (or at least, to the limits of double precision), with no loss of detail. The information for the dataset is extracted through fractal calculations, rather than stored as hard data in a database, so it is feasible to construct a fractal planet simulation on a desktop system. Look into techniques such as Perlin noise, which can be magnified or refined at lower and lower sampling rates, and will return coherent and meaningful data at those lower levels.

Some links turned up by Google:
Fractal planets (Paul Bourke''s fractal planet page)
Building fractal planets (Ken Musgrave''s site in general is an interesting one if you are into fractals)

To solve this problem--especially, to be able to zoom in on a full-sized planet--will require some heavy thinking to come up with the fractal generators, and to overcome the limitations of double floating point precision. Even a double will begin to show artifacts as you zoom in on a full-scale planet. Accomplishing this in real-time for a game might be really more than most current systems can realistically manage.

Best of luck.


Golem
Blender--The Gimp--Python--Lua--SDL
Nethack--Crawl--ADOM--Angband--Dungeondweller

Share this post


Link to post
Share on other sites