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For my current project http://www.gamedev.net/blog/blog-807/cat-252-strife I was thinking of more ways to ceaply render massive amounts of far of terrain (7 km in all directions from the player). Currently I use a LOD aproach where the the resolution of the heightmap reduces with range and at the same time I draw bigger blocks of terrain in one draw call. (for example the terrain the player stands on would be a 128x128 vertice mesh that stretches over 128x128 meters ingame but a a 1024x1024 meter block thats 5 km away would be rendered using a 16x16 vertice mesh. So together with some frustum culling my solution gives acceptable results.
But now ive thought of another. That might allow me to go easier on the LOD (if I LOD too severly mountains in the distance might become a little spiky, not too bad but not ideal either).
What I i was thinking was to build up a skybox over a period of X frames. (lets say 120 for arguments sake). this skybox would contain all far of terrain and as soon as its done it will display it and imediatly start to build a new one.
Il elaborate. I want to render the far off terrain to a skybox texture over a perion of 120 frames (in other words it will render a little bit every frame) and when its done it will set that texture as the current skybox and start again in the background on a new one. seeing as the player in the game wont ever be moving very fast the changes in the distant terrain should not be noticeble over a 2 second timeframe. This method will thus allow you to do fairly detailed terrain rendering for far of terrain without it having a significant performance cost. Or so i think
. Of course you cant do frustum culling on the far of terrain if you do this since the player can easly turn 180 degrees in 2 seconds but i even so i think it will work.with far of terrain in my case i mean terrain futher away than 1.5 km. so in the case of my current project 1.5km - 7 km.
Is this technique used in games allready? is it feasable? what am i missing here.
Thnx in Advance!
