Rendering Forest Scenes in Real-Time

Forests are crucial for scene realism in applications such as flight simulators. This paper proposes a new representation allowing for the real-time rendering of realistic forests covering an arbitrary terrain. It lets us produce dense forests corresponding to continuous non-repetitive fields made of thousands of trees with full parallax. Our representation draws on volumetric textures and aperiodic tiling: the forest consists of a set of edgecompatible prisms containing forest samples which are aperiodically mapped onto the ground. The representation allows for quality rendering, thanks to appropriate 3D non-linear filtering. It relies on LODs and on a GPUfriendly structure to achieve real-time performance. Dynamic lighting and shadowing are beyond the scope of this paper. On the other hand, we require no advanced graphics feature except 3D textures and decent fill and vertex transform rates. However we can take advantage of vertex shaders so that the slicing of the volumetric texture is entirely done on the GPU.