Fenney, SimonOzkan, AlperBikker, JaccoGribble, Christiaan2023-06-252023-06-252023978-3-03868-229-52079-8687https://doi.org/10.2312/hpg.20231133https://diglib.eg.org:443/handle/10.2312/hpg20231133Recently, schemes have been proposed for accelerating 'alpha-tested' triangles in ray-tracing through the use of precomputed, three-level Opacity Masks/Maps that can significantly reduce the need for expensive of 'Any-Hit shader' invocations. We propose and compare two related schemes, VQ2 and VQ4, of compressing such maps that provide both random access and low-cost decompression. Each compressed opacity map, however, relates to a pair of adjacent triangles, taking advantage of correlation across the shared edge and matching likely underlying hardware primitive models.Attribution 4.0 International LicenseCCS Concepts: Computing methodologies -> Ray tracing; VisibilityComputing methodologiesRay tracingVisibility10.2312/hpg.2023113323-319 pages