Abstract
Terrains are challenging geometric objects for real-timerendering and interactive manipulation. State-of-the-artterrain rendering systems use custom, multiresolution, rep-resentations like geometry clipmaps for fast rendering onthe GPU. In this paper, we present a system that exploitsthe power and flexibility of the modern GPUs to store, ren-der, and manipulate terrains with minimal CPU involve-ment. The central idea is to use a regular-grid represen-tation and fixed size blocks/tiles that change in resolution.The potentially visible portion of the terrain is cached atthe highest necessary resolution and is rendered from theGPU. The CPU sends a light geometry template which isexpanded by the Geometry Shader to the triangles, usingthe heights stored in the GPU Cache. The CPU performsa coarse culling of the tiles with the GPU performing fineculling. The GPU cache is updated continuously as theviewpoint changes. Our system enables the terrain to bemodified procedurally or edited interactively on the GPUwith no CPU involvement. The terrain can also interactwith a large number of external objects in real-time entirelywithin the GPU. We achieve a consistent rendering rate of100 frames per second with terrain modification and inter-actions as well as a triangle rate of upto 350 million persecond on an Nvidia 8800 GTX GPU for large terrains, witha CPU load below 10%.