Effective Multi-resolution Rendering and Texture Compression for Captured Volumetric Trees

Trees can be realistically rendered in synthetic environments by creating volumetric representations from photographs. Volumetric trees created with previous methods are expensive to render due to the high number of primitives, and have very high texture memory requirements. We present an efficient multi-resolution rendering method and an effective texture compression solution, addressing both shortcomings. Our method uses an octree with appropriate textures at intermediate hierarchy levels and applies an effective pruning strategy. For texture compression, we adapt a vector quantization approach to use a perceptually accurate colour space, and modify the codebook generation of the Generalized Lloyd Algorithm to further improve texture quality. Combined with several hardware accelerations, our approach achieves a two orders of magnitude reduction in texture memory requirements; in addition, it is now possible to render tens or even hundreds of captured trees at interactive rates