From d9dfc1913d42bec5d02a1fa7f9ff01bbcd194325 Mon Sep 17 00:00:00 2001
From: WarmUpTill <WarmUpTill@web.de>
Date: Sat, 24 Apr 2021 23:57:45 +0200
Subject: [PATCH] Fix previous scene not working for some sequences

If a duration for a transition is used that is longer than the scene
switcher check interval it could happen that the "incorrect" previous
scene could be chosen for uninterruptible scene sequences, as at the
time the sequence check was preformed the "previous scene" variable
was not yet updated as the transition was still ongoing.
---
 src/advanced-scene-switcher.cpp       | 17 +++++++++++++----
 src/headers/switcher-data-structs.hpp |  4 ++--
 src/switch-sequence.cpp               |  6 +++++-
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/src/advanced-scene-switcher.cpp b/src/advanced-scene-switcher.cpp
index 041514f8..f0c09900 100644
--- a/src/advanced-scene-switcher.cpp
+++ b/src/advanced-scene-switcher.cpp
@@ -479,6 +479,9 @@ void SwitcherData::Thread()
 		bool match = false;
 		OBSWeakSource scene;
 		OBSWeakSource transition;
+		// The previous scene might have changed during the linger duration,
+		// if a longer transition is used than the configured check interval
+		bool setPrevSceneAfterLinger = false;
 
 		endTime = std::chrono::high_resolution_clock::now();
 
@@ -512,7 +515,8 @@ void SwitcherData::Thread()
 		if (checkPause()) {
 			continue;
 		}
-		match = checkForMatch(scene, transition, linger);
+		match = checkForMatch(scene, transition, linger,
+				      setPrevSceneAfterLinger);
 		if (switcher->stop) {
 			break;
 		}
@@ -536,6 +540,8 @@ void SwitcherData::Thread()
 
 				match = false;
 				linger = 0;
+			} else if (setPrevSceneAfterLinger) {
+				scene = previousScene;
 			}
 		}
 
@@ -563,12 +569,14 @@ void SwitcherData::Thread()
 }
 
 bool SwitcherData::checkForMatch(OBSWeakSource &scene,
-				 OBSWeakSource &transition, int &linger)
+				 OBSWeakSource &transition, int &linger,
+				 bool &setPrevSceneAfterLinger)
 {
 	bool match = false;
 
 	if (uninterruptibleSceneSequenceActive) {
-		match = checkSceneSequence(scene, transition, linger);
+		match = checkSceneSequence(scene, transition, linger,
+					   setPrevSceneAfterLinger);
 		if (match) {
 			return match;
 		}
@@ -593,7 +601,8 @@ bool SwitcherData::checkForMatch(OBSWeakSource &scene,
 			match = checkWindowTitleSwitch(scene, transition);
 			break;
 		case round_trip_func:
-			match = checkSceneSequence(scene, transition, linger);
+			match = checkSceneSequence(scene, transition, linger,
+						   setPrevSceneAfterLinger);
 			break;
 		case media_func:
 			match = checkMediaSwitch(scene, transition);
diff --git a/src/headers/switcher-data-structs.hpp b/src/headers/switcher-data-structs.hpp
index faaadb36..2d36c6e9 100644
--- a/src/headers/switcher-data-structs.hpp
+++ b/src/headers/switcher-data-structs.hpp
@@ -188,9 +188,9 @@ struct SwitcherData {
 	void writeToStatusFile(QString status);
 
 	bool checkForMatch(OBSWeakSource &scene, OBSWeakSource &transition,
-			   int &linger);
+			   int &linger, bool &setPreviousSceneAsMatch);
 	bool checkSceneSequence(OBSWeakSource &scene, OBSWeakSource &transition,
-				int &linger);
+				int &linger, bool &setPrevSceneAfterLinger);
 	bool checkIdleSwitch(OBSWeakSource &scene, OBSWeakSource &transition);
 	bool checkWindowTitleSwitch(OBSWeakSource &scene,
 				    OBSWeakSource &transition);
diff --git a/src/switch-sequence.cpp b/src/switch-sequence.cpp
index 7c820b6a..611c0b73 100644
--- a/src/switch-sequence.cpp
+++ b/src/switch-sequence.cpp
@@ -180,7 +180,8 @@ void AdvSceneSwitcher::on_sceneSequenceSwitches_itemDoubleClicked(
 }
 
 bool SwitcherData::checkSceneSequence(OBSWeakSource &scene,
-				      OBSWeakSource &transition, int &linger)
+				      OBSWeakSource &transition, int &linger,
+				      bool &setPrevSceneAfterLinger)
 {
 	if (SceneSequenceSwitch::pause) {
 		return false;
@@ -206,9 +207,12 @@ bool SwitcherData::checkSceneSequence(OBSWeakSource &scene,
 			if (s.activeSequence) {
 				scene = s.activeSequence->getScene();
 				transition = s.activeSequence->transition;
+				setPrevSceneAfterLinger =
+					s.activeSequence->usePreviousScene;
 			} else {
 				scene = s.getScene();
 				transition = s.transition;
+				setPrevSceneAfterLinger = s.usePreviousScene;
 				if (verbose) {
 					s.logMatch();
 				}