Precomputing Geometry-Based Reverberation Effects for Games

Current video games either pre-render reverberation effects into the sound effects or implement them at run-time using artificial reverberation filters. While interactive geometrical approaches can be used for more accurate acoustical modeling, the increased authoring complexity and the additional cost of geometrical calculations still appears to overshadow their potential benefits. This paper presents solutions to integrate off-line geometrical acoustic modeling in game environments. By pre-computing image-source gradients for early reflections and directional decay profiles, we can generate location dependent reverberation effects without storing or accessing the actual geometry at run-time. We render such reverberation effects using a frequency-domain scalable processing approach. In this context, we introduce an efficient prioritization scheme and evaluate alternative transforms for late reverberation processing. Our pipeline enables fine-grain rendering of distance and surface proximity effects and modeling of both outdoor and coupled indoor spaces with arbitrary reverberation decay profiles.