Looping OpenAL sounds with one buffer - or how to do it correctly?

Question

I require to implement a statically played sound class which supports looping of the audio data - and requires this to be changed at runtime (e.g., turning off looping).

Maybe I understand something horribly wrong, but this is how I understood how to implement looping at all, and came to the following solution:

• I have exactly one buffer containing all the audio data.

• If looping is enabled, ensure that the source playing the sound has this buffer queued twice, so it replays the sound when the end of the current buffer has been reached:

  if (Loop && _source.BuffersQueued == 1)
  {
      _source.QueueBuffers(_buffer);
  }
  

• If a buffer has been processed (e.g. right after the sound audibly loops), it is unqueued and dismissed.

  if (_source.BuffersProcessed > 0)
  {
      _source.UnqueueBuffers(_source.BuffersProcessed); // Unqueue outdated buffers
  }
  

Here I ran into the first problem: If the user sets the sound to not loop anymore, I cannot unqueue the upcoming buffer (to make it not loop over another time while looping has already been turned off).

This is because I only found methods to unqueue by the handle of the buffer, but since I queue the same buffer twice, the handle is always the same to the one currently playing. OpenAL tries to unqueue the currently played buffer then, which obviously fails.

Unqueuing by the number of processed buffers also doesn't help, as no buffer has been marked as processed yet.

Do I really need to completely duplicate the buffer with all the audio data, keep it stored twice in memory, just to have two different buffer handles to unqueue the second buffer if looping gets disabled?

Answer 1

There is a simpler way to do looping:

alSourcei(source, AL_LOOPING, 1); enables it for a source and
alSourcei(source, AL_LOOPING, 0); disables it.