Useful literature and tutorials

The Virtual Terrain Project — an outstanding resource for all things terrain.

NeHe Productions — many excellent OpenGL tutorials.

Beautiful Landscapes By Means Of Height Mapping, B. Humphrey (via NeHe OpenGL tutorials).

Real-Time Dynamic Level of Detail Terrain Rendering with ROAM, B. Turner (via GamaSutra.com) — used for sapphire renderer.

ROAMing Terrain: Real-time Optimally Adapting Meshes, M. Duchaineau et. al.

Hardware Based Terrain Clipmapping, A. Holkner.

The Clipmap: A Virtual Mipmap, C. C. Tanner, C. J. Migdal, M. T. Jones.

Understanding and Using OpenGL Texture Objects, R. Wright (via GamaSutra.com) — used for sapphire renderer.