Triton: Practical pre-computed sound propagation for games and virtual reality

Abstract

Triton is a pre-computed wave-based acoustics system recently shipped in the game “Gears of War 4.” Games and VR present exciting new opportunities for virtual acoustics by providing the player with scene-dependent reverberation cues and conveying information about visually occluded areas. Several technical challenges must be met. Scenes containing millions of polygons are common, with mixed indoor-outdoor spaces like broken buildings, courtyards, caves, and rocks. A viable technique must handle this complex visual geometry without users' intervention. The emphasis is on ensuring the resulting auralization is perceptually convincing, varying smoothly on source and listener motion in such scenes. Highly occluded cases with salient paths undergoing multiple edge-diffraction and scattering are common. Computational requirements are quite stringent. A fraction of a single CPU core must be used for acoustic calculations for many tens of moving sources. We discuss how these challenges shape Triton’s design. Pre-computation is used to minimize runtime cost. Wave simulation provides complete automation for complex scene geometry. The produced fields contain billions of responses that take terabytes of memory. A key contribution is compact encoding of this data in less than hundred megabytes: objective room acoustic parameters are approached from a novel perspective to aid in spatial compression. The resulting parametric framework is fast and practical for current games and VR applications. Video demonstrations will be shown.