Tetrahedral Projection using Vertex Shaders

"Tetrahedral Projection using Vertex Shaders." Brian Wylie, Kenneth Moreland, Lee Ann Fisk, and Patricia Crossno. In Proceedings of IEEE Volume Visualization and Graphics Symposium 2002, October 2002, pp. 7–12.

Abstract

Projective methods for volume rendering currently represent the best approach for interactive visualization of unstructured data sets. We present a technique for tetrahedral projection using the programmable vertex shaders on current generation commodity graphics cards. The technique is based on Shirley and Tuchman's Projected Tetrahedra (PT) algorithm and allows tetrahedral elements to be volume scan converted within the graphics processing unit. Our technique requires no pre-processing of the data and no additional data structures. Our initial implementation allows interactive viewing of large unstructured datasets on a desktop personal computer.

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Supplemental Materials

Vertex program for the GL_NV_vertex_program OpenGL extension.
Vertex program for the GL_ARB_vertex_program/shader extensions.
List of uniform parameters that need to be loaded.
Example OpenGL code that loads the vertex program.
Cg vertex program that also implements the tetrahedral projection.