Building An OpenAL Implementation Using Ambisonics

摘要

OpenAL allows 3D spatialization to be provided from outside game code; new implementations can be "plugged in". Ambisonics separates an abstract soundfield representation from actual speaker feeds and allows decoding to large number of speakers, including arrangements in 3D. We present the design of an Ambisonic OpenAL driver implemented in three segments: an "environment" managing state, a "renderer" using this state to generate an abstract Ambisonic soundfield representation and a "decoder" which applies whatever decoding algorithm is desired and feeds the available hardware. We also describe techniques to decode for surround stereo and headphones.