Real-Time Acoustical Diffraction and First-Order Specular Reflection Modeling Using the GPU

Although the inclusion of spatial sound cues in virtual environments and video games can lead to increases in presence and immersion, spatial sound cues are often overlooked and neglected by designers of virtual environments and video games. However, simulating the propagation of a sound after being emitted from a sound source until it reaches the listener can be computationally very expensive given the potentially huge number of interactions that must be accounted for. Sound can be reflected specularly, diffusely, be refracted and diffracted in the presence of an occluding object/obstacle but for simplicity, diffraction is completely ignored despite the fact that diffraction is an important means of sound propagation. Driven by the gaming industry, consumer computer graphics hardware and the graphics processing unit (GPU) in particular, has greatly advanced in recent years, outperforming the computational capacity of central processing units (CPUs). Given the widespread use and availability of computer graphics hardware, a recent initiative involves the application of GPUs to spatial sound generation and processing. Here we describe a computationally efficient GPU-based acoustical occlusion method that approximates acoustical occlusion/diffraction and first order specular reflection effects for real-time, dynamic, and interactive virtual environments and video games.