ofOpenALSoundPlayer uses a thread internally does not appear thread-safe

ofOpenALSoundPlayer looks like it ought to have locks around all of its functions. it's using a threadedFunction to handle updating/processing the sound playback streams in a background thread.

although OpenAL is itself thread-safe, our code is not thread safe. for example unloadSound deletes channels and sources but if it does this while threadedFunction() is running so a channel might become invalid halfway through updating it on our side, leading to for example a bad buffer reference being passed to different functions.

also, handling of stream_end is broken. if in the main thread stream_end is assigned true while the threadedFunction is executing code between https://github.com/openframeworks/openFrameworks/blob/master/libs/openFrameworks/sound/ofOpenALSoundPlayer.cpp#L505 and line 520, when line 521 executes the value of stream_end is assigned back to false and the stream will not end.

Start in libs/openFrameworks/sound/ofOpenALSoundPlayer.cpp, especially threadedFunction() and the code around lines 505–521, then inspect unloadSound and related playback functions. Reproduce or reason through concurrent stream updates and unloading; done means shared state remains consistent and stream_end is not incorrectly cleared during background processing.