Is OpenAL open-source?
I need to change something in it and I can't find the source code of it.
I checked the official OpenAL website too, but found nothing.
"Open" in OpenAL doesn't mean an open source. As in case of OpenGL, the main idea was an open specification of the library implemented by various hardware vendors.
OpenAL has been initially pushed by Creative to promote hardware features of their Audio cards, but nowadays the most active project is an open source library OpenAL-soft under LGPL: https://github.com/kcat/openal-soft
Documentation of this project has a weak reference to an older one:
It's forked from the open-sourced Windows version available originally from openal.org's SVN repository (now defunct)
The original project is defunct for a long time, but you may find a mirror on GitHub. Cannot say if it is of any use - I would better stick to OpenAL soft and consider the old project only for archeological researches: https://github.com/rpavlik/openal-svn-mirror