Fast Terrain Rendering with Continuous Detail on a Modern GPU

Terrain rendering is challenging. It requires both high detail close to the camera and a large extent. There must be less detail per square meter in the distance to render this efficiently (and ideally, the amount of detail per pixel would be about the same), but the transitions from high to low detail should be imperceptible.

There's been a lot of research and development on terrain rendering systems. The best systems today can render worlds in which the viewer can pull back continuously from individual stones and flowers to observing entire planets from space, and when looking at the flowers can still see mountains in the distance. The underlying perception, art, and geometric issues of course remain unchanged over time, but hardware architectures and available resources change dramatically. So, terrain rendering methods that were preferred even a few years ago (e.g., ROAM, geomipmapping, projective grid) may be obsolete today. (Today's methods will likely be obsolete in a few more years). Fortunately, the last few hardware generations have moved in a direction where the currently-preferred implementations are more simple to implement than the previously-preferred ones.



In this post I describe a terrain renderer that I built with some current best practices. It draws on a lot of other blog posts and research articles that I'll mention in passing. My implementation renders in 3.4 ms at 1680x1050 resolution on NVIDIA GeForce 650M under Windows 7 (i.e., on a MacBook 2012 Pro under boot camp), and supports both forward and deferred shading. It is written in OpenGL using the G3D Innovation Engine 10.0 beta (SVN revision 4283) and I provide the full source code. I don't expect anyone to compile and run that code directly, however. I'm releasing it without support (i.e., I'm always happy to discuss algorithms, but please don't ask me for help dealing with your compiler/library/installation) to help others with their own implementations and as a case study in GPU optimization of large mesh rendering.