Texture-encoded tetrahedral strips

The use of triangle strips is a common method to compactly store and efficiently render large polygonal meshes. The advantages of triangle stripification also apply to tetrahedral meshes; therefore, tetrahedral strips are an attractive data structure for storing and volume rendering tetrahedral meshes as noted in several publications. However, tetrahedral strips are still not supported by current graphics hardware. In this paper, we present the first system to take advantage of tetrahedral strips in off-the-shelf graphics hardware. This is achieved by encoding tetrahedral strips in texture maps and rendering them with the help of a ray casting algorithm running solely on the graphics chip. Our data structure supports sequential and generalized tetrahedral strips by including a small amount of adjacency information, which allows us to access all face neighbors in constant time. Utilizing these texture-encoded tetrahedral strips, our enhanced graphics-hardware-based volume ray casting algorithm for tetrahedral meshes is capable of handling large data sets. Additional improvements presented in this paper include support for multiple ray traversal steps in one rendering pass and the intrinsic support for non-convex meshes using a rendering technique similar to depth peeling.