Posted: Tue Mar 09, 2010 2:25 pm
Irrlicht provides mipmap access since Irrlicht 1.7. So everything should work as expected 

Official forum of the Irrlicht Engine
https://irrlicht.sourceforge.io/forum/
Depending on the desired use of terrain; if your intent is to give the impression of and endless world, one could repeat/tile the terrain like the Tribes series games.Again, my thinking around truly endless terrain, shifting into a newly loaded terrain would need to have the old one removed to conserve memory. In theory, using files, we should be able to construct many terrains, load them, unload them etc. I know this is far reaching however, if indeed your in a rewrite, maybe you could consider some of these idea's.
If say you have three 1024 terrains complete with hightmaps, in a truly enless world, we should be able to place these terrains in locations. in the "grid" for a lack of a better term. And where there are empty places in the grid, produce a random terrain. If my knowledge of this were hightened by a large percent, I would surely help you with this amazing task.