SLOBS frontend: soak first mac-virtualcam start event

* Commit c85d4fa renames virtualcam events into start & stop. Problem
is OBS frontend will always assume the user has started the virtualcam now.
Unfortunately now there is a modal popup that is
displayed if you attempt to close OBS because it thinks you started
virtualcam (when you didnt). This change at least gets rid of the modal
dialog when you run SLOBS backend

Author: sandboxcoder

frontend/utility/BasicOutputHandler.cpp

@@ -144,7 +144,13 @@ void OBSReplayBufferSaved(void *data, calldata_t * /* params */)
 static void OBSStartVirtualCam(void *data, calldata_t * /* params */)
 {
 	BasicOutputHandler *output = static_cast<BasicOutputHandler *>(data);
-
+#ifdef __APPLE__
+	// Streamlabs - Suppress first "start" signal from mac-virtualcam which is spun up automatically by OBS. SLD doesnt work this way
+	if (!output->hasReceivedStartSignal) {
+		output->hasReceivedStartSignal = true;
+		return;
+	}
+#endif
 	output->virtualCamActive = true;
 	os_atomic_set_bool(&virtualcam_active, true);
 	QMetaObject::invokeMethod(output->main, "OnVirtualCamStart");

frontend/utility/BasicOutputHandler.hpp

@@ -25,6 +25,7 @@ struct BasicOutputHandler {
 	bool delayActive = false;
 	bool replayBufferActive = false;
 	bool virtualCamActive = false;
+	bool hasReceivedStartSignal = false; // Streamlabs - ignore first signal
 	OBSBasic *main;
 
 	std::unique_ptr<MultitrackVideoOutput> multitrackVideo;