Real-Time Programmable Volume Rendering

Real-time graphics hardware is rapidly becoming programmable, and has recently incorporated the features needed for direct volume rendering. Unfortunately, the standard interfaces to this hardware are at the assembly language level. When programming at this level, it is difficult re-use and modify existing implementations of volume rendering algorithms, and it is extremely tedious to experiment with the many possible tradeoffs between performance, visualization technique, and image quality. We address these problems with a programmable volume rendering pipeline that is implemented in a high-level shading language, and executes efficiently on commodity graphics hardware. We show how to write re-usable code modules for a variety of volume resampling, classification and shading algorithms, and demonstrate how these modules can be combined in mix-and-match fashion to build custom pipelines. We present results on current hardware.