Controlling GPU-based Volume Rendering using Ray Textures

In this paper we introduce a novel approach to control different rendering parameters of volume ray casting. Since the introduction of ray casting implementations on programmable graphics hardware, both performance and flexibility have increased and are able to outperform texture-based techniques. In addition, by using rays for computing the volume integral instead of proxy geometry one has more control over local settings. Therefore, we employ dependent texture lookups to user editable 2D textures, thus allowing for interactive parameter setting on a per-ray basis, at a negligible performance overhead on modem graphics hardware. By those means we are able to control the volume rendering in a way not possible with proxy-based direct volume rendering and demonstrate some exemplary uses.