A Real-Time Physically Based Algorithm for Hard Shadows on Dynamic Height-Fields

Abstract

Bump maps are commonly used in computer graphics to visualize bumps and wrinkles on the surface of an object, more specifically, in height-field rendering. In order to render shadows for large terrain data using bump maps, various methods such as horizon mapping have been suggested. A horizon map describes the occlusion of terrain data by using angles with respect to a view point. In this paper, we propose a method exploiting ideas from horizon mapping to generate real time shadows for large terrain data. We only consider a single azimuth direction per height-field point to compute the shadows. The generated horizon map is computed in real time and allows for interactive exploration of the terrain. We demonstrate that our method produces accurate results while keeping the memory requirements low