Hardware Accelerated Terrain Rendering by Adaptive Slicing
Stefan Röttger, Thomas Ertl · 2001
Many terrain rendering algorithms have been developed, which perform a variety of mesh optimizations to achieve interactive frame rates. The most prominent approach is the so called continuous level of detail technique, which approximates a terrain by computing a view-dependent triangulation. One disadvantage of this approach is the fact that the rendered terrain is of course just an approximation of the original data set. By exploiting the capabilities of todays mainstream PC graphics accelerators we propose a new technique for the exact rendering of height fields. Due to its relationship with volume slicing we call it adaptive terrain slicing. This technique is adaptive in the sense that a bundle of slices is used to sample the terrain, whereas the number of slices is determined to assure sub-pixel accuracy. The core of our approach is a hierarchical bounding box representation of the terrain, which is traversed in a top-down order. During traversal we calculate the actual rendering costs of our adaptive terrain slicing approach, which enables us to decide whether it would be faster to render the contents of the actual bounding box or to descend further down the hierarchy. After that the minimized terrain slicing costs are compared to the cost of polygonal rendering and the faster method of both is applied. Since the speed of our terrain slicing approach is limited mainly by the rasterization bandwidth of the graphics hardware, we can efficiently decouple the rendering costs from geometric complexity leading to high frame rates without compromising image quality. In particular, our approach is well suited for replacing the commonly used bump maps with the visually more pleasing displacement maps.