Hi Airplane/submarine simulation world: Just played some silent hunter 3 and started working on some ideas. How would i go about doing the world? I mean most of the seas can just be flat-bottom (its very deep anyway) but all the landmass and shallow parts like in rivers etc? Ideally i would like to do huge maps like the mediterrainian sea:) I know a little about heightmaps and have experimented a bit with them. Would the world consist of myriads of sections, each defined by a heightmap? And then load (and build) and unload the heightmap as the player moves in the world? Thanks for your input Erik

Thats a pretty open ended question!

The easiest approach is probably just to take heightmaps (lots of if your thinking the size of the med) that are edited as 16bit greyscale images. If you want to get more inventive there are a billion papers on terrain LOD systems (ROAM etc).

However - if you want to make a game and have limited resources and don't want to get hung up on the myriad of implementation details I would advise you to KISS [keep it simple stupid]. Height maps have excellent existing editors (painting programs) are easy to understand for the data creator (normally non technical artist type) and are easy to turn into renderable data! If you don't need overhangs they're almost ideal ;)

-Tom

What are overhangs?
So the simple idea (your second suggestion) is basically what i said, use heightmaps in a tilesystem. I didnt understand the other suggestion. Is that the use of LOD systems? But i need some LOD right, i cannot draw my entire world...

There's a lot of old games in the flying-sim apartment. I guess they use geightmaps with very low "resolution" (a pic of 256x256 pixels are used for a very large peice of the world).

Why do you suggest 16bit pics? To save space? Standard bitmap is 24bits i think.
thanks
E

Bit depth selection really depends on height range required vs the resolution you need to display. The fewer bits used the less memory you require (perhaps allowing you to avoid "streaming" data - esp with some compression involved) which will also impact performance (memory reads can be pretty expensive).

24 seems likely to be an overkill in terms of range and accuracy. 16 bits gives you a lot of accuracy over a width range (for instance 0.5 foot intervals for a 30000 ft range). It also packs nicely into 32bit memory boundaries.

As for LOD - as I say there are a gazillion papers out there. You might want to start looking somewhere like this: http://www.vterrain.org/LOD/Papers/

Overhangs are might be seen where you have a vertical cliff. Heightmaps can't represent this. The more vertical you go the more UV stretch you'll see. This might not be an issue for your chosen game.

Choose your solution carefully - do you want to make a game or spend your time investigating / developing the perfect terrain engine ;)

Maybe you want to grab an off the shelf solution?