Method process

src/MidiThing.cpp:42–69

if a channel (0 - 11) should be updated, return it's index, otherwise return -1

struct RoundRobinProcessor {
	// if a channel (0 - 11) should be updated, return it's index, otherwise return -1
	int process(float sampleTime, float period, int numActiveChannels) {

		if (numActiveChannels == 0 || period <= 0) {
			return -1;
		}

		time += sampleTime;

		if (time > period) {
			time -= period;

			// special case: when there's only one channel, the below logic (which looks for when active channel changes)
			// wont fire. as we've completed a period, return an "update channel 0" value
			if (numActiveChannels == 1) {
				return 0;
			}
		}

		int currentActiveChannel = numActiveChannels * time / period;

		if (currentActiveChannel != previousActiveChannel) {
			previousActiveChannel = currentActiveChannel;
			return currentActiveChannel;
		}

		// if we've got this far, no updates needed (-1)
		return -1;
	}
private:
	float time = 0.f;
	int previousActiveChannel = -1;