Loop playback and host synchronization

[szk2s]

Thank you for releasing such a wonderful library. I am making good use of it.

I am trying to create a sequencer plugin, but I am encountering some issues. I'm not sure if it's a bug or an intentional design, so I decided to post here in the discussion first.

Plugin I want to create

I want to make the functionality of the StepSequencerDemo available as a DAW plugin. In other words, I want to loop-play the Edit while synchronizing with the host's playback position.

What I tried

I set it up to synchronize with the host using ExternalPlayheadSynchroniser, similar to EngineInPluginDemo.h. At the same time, I set up the loop as follows:

te::BeatRange loopBeatRange {{}, te::BeatDuration::fromBeats(4)};
te::TimeRange loopTimeRange = edit->tempoSequence.toTime(loopBeatRange);
edit->getTransport().setLoopRange(loopTimeRange);
edit->getTransport().looping = true;

The behavior I expect is that, regardless of the host's playback position, the first measure (4 beats) of the Edit will loop-play. However, when I tested it with Ableton Live and Reaper, only the first 4 beats of the Edit played, and then noise occurred.

Questions

• Is this behavior an intentional design or a bug?
• To achieve the behavior I desire, it seems like I should define a class similar to ExternalPlayheadSynchroniser myself. Is this the right direction, or is there an existing class that I might have overlooked that can achieve this?

[szk2s]

To be clear, I want to achieve the following synchronization.

Host Playhead	Edit Playhead
0	0
1	1
2	2
3	3
4	0
5	1
6	2
7	3
8	0

And looping around a single clip is not what I'm seeking for. My plugin plays a pattern which contains multiple audio clips.