Multiple Layer Displacement Mapping with Lossless Image Compression
AbstractWe introduce a lossless compression and rendering technique for a multiple layer displacement map. Compressed data are handled in GPU for real-time rendering. A multiple layer displacement map is useful in representing general objects which cannot be represented by a single layer displacement map. Multiple layer displacement mapping methods can provide realistic objects in digital content such as 3D games and films for relatively low costs. For this, we have to use many layers to represent high quality object details. However, in a multiple layer displacement map, the first layer has the most data and the lower layers have less data. Therefore, lower layers waste data space, because the same space is allocated for every layer. We only store data used for rendering and make an address map to refer to the stored data. We also compress additional information such as normal vectors and diffuse colors. The main advantage is that all the compressed data share just one address map, and compression efficiency will improve when we use more layers. Since we compress the maps without any data loss, the proposed technique provides the same quality as rendering with the original maps.KeywordsDisplacement mappingLossless image compressionReal-time rendering