Blend Maps: Enhanced Terrain Texturing

Abstract

Very large textures are prohibitive for most interactive terrain rendering. Alternatively, tiled textures can be linearly blended to produce interesting transitions between predefined textures. However, these transitions seldom work well when the texture frequency content is not high. This paper introduces blend maps, a technique used to enhance the blending of textures so that features of the underlying texture are maintained or emphasised. The resulting texture appears more realistic in many cases, and adds to the perceived detail of the terrain. Blend maps are constructed by identifying important features in a texture. These features are often highlighted under certain lighting conditions. The blend maps are created manually, but some automation is possible. The importance is then used to control a blending operation in such a way that features can be preserved. The proposed algorithm is simple enough to allow realtime rendering on modern graphics hardware.