Geo-mip-mapping

Cited Tutorial

Geo-mip-mapping and texture splatting 

So what is geo-mip-mapping? 

It is a technique used to create different levels of detail for terrains efficiently. 

The terrain gets split up into a couple of quadratic tiles. Each of these tiles has five different LoDs with a triangle count in the range from 512 to 2. Due to the efficient structure of the LoDs all of them can use the same vertex buffer. The following graphic illustrates how the different LoDs look

  Depending on the height difference of the tile and the distance to the camera, Ultimate 3D will decide which level of detail is to be used for rendering the tile. This extreme variety of the LoDs makes the terrain renderer incredibly efficient. One problem you are confronted with frequently when rendering terrain, is how to get good textures for the terrain. Every part of the terrain should have a different color, but a texture that covers the whole terrain would be either extremely big or extremely undetailed. Neither is desirable. One technique to avoid this is the use of a detail map, but that does not look very good.