Valve have just opened sourced their 3D audio solution Steam Audio that was used in such games as Half Life: Alyx and DOTA 2. The code has been released, along side with the code for the Unreal Engine and Unity plugins, on GitHub under the liberal Apache-2 open source license.
Details of the release from the Steam Community news article:
We are excited to announce that with the latest release of Steam Audio, the complete source code of the Steam Audio SDK is now available as open source. With this release, our goal is to provide more control to developers, which will lead to better experiences for their users, and hopefully valuable contributions back to the wider community of developers using Steam Audio.
This comes after receiving a lot of valuable feedback and contributions from the community to the plugins already available as open source (Unity, Unreal, and FMOD Studio), and we want to bring those same benefits to the core SDK. This will allow developers to tailor the SDK to their needs, and deliver improved experiences to everyone using the technology. We will also continue our ongoing work on Steam Audio, including the release of bug fixes and new features.
The choice of what features we work on is often driven by the needs of internal projects. For instance, during the development of Half-Life: Alyx, we spent a lot of time working on our hybrid reverb and pathing features, which we later released as part of Steam Audio 4.0.0. These priorities might not always align with partner priorities, so we want to remove roadblocks that prevent partners from implementing spatial audio features that require access to the core Steam Audio SDK. As an example, we may be working on fixing a performance issue in Steam Audio affecting an internal project, but a partner may need Steam Audio ported to a console platform. Making the entire SDK available as open source allows partners to manage the port themselves, and optimize it for their needs, while also allowing them to contribute their changes back if desired.
The entire Steam Audio codebase, including both the SDK and all plugins, is now released under the Apache 2.0 license. This allows developers to use Steam Audio in commercial products, and to modify or redistribute it under their own licensing terms without having to include source code. We welcome contributions from developers who would like to fix bugs or add features to Steam Audio; for more details, see the files LICENSE.md and CONTRIBUTING.md in the GitHub repository.
Key Links
Open Source Release Announcement
If you want to learn more about Valve Software open sourcing the Steam Audio SDK watch the video below.