John Carmack PCGamer interview...next engine to have "unique texturing on everything"

[Rodéric]

If iD Tech 5 MegaTexture is close to ET:Quake Wars, then it's a simple clipmap.
(or so it seemed to me overlooking the shaders)

The mipmap selection can be done software, taking filerting mode into account.

 

[Laa-Yosh]

It's probably far more complex, as it's not just on the terrain but on everything. And the terrain itself is quite more complex then QW, too - not just a simple height field.

 

[Richard]

It's probably far more complex, as it's not just on the terrain but on everything. And the terrain itself is quite more complex then QW, too - not just a simple height field.

QW's terrains are not height fields either.

 

[Laa-Yosh]

They don't seem to have overlapping geometry, that's what I've meant. They look like simple grids displaced on the vertical axis, whereas Rage has totaly arbitrary structures for terrain.

Point is, it's a lot more complex then clip maps.

 

[Richard]

They don't seem to have overlapping geometry, that's what I've meant. They look like simple grids displaced on the vertical axis, whereas Rage has totaly arbitrary structures for terrain.

That's how ETQW's megatexture works but the terrain models themselves do have overlapping geometry is a few places. Here's one: