UI: Change certain scene functions to slot functions

This allows using the functions via Qt message queue.  The reason for
this is so a frontend API can queue these functions to call safely from
another thread.

UI/window-basic-main-transitions.cpp

@@ -220,7 +220,7 @@ obs_source_t *OBSBasic::FindTransition(const char *name)
 	return nullptr;
 }
 
-void OBSBasic::TransitionToScene(obs_scene_t *scene, bool force)
+void OBSBasic::TransitionToScene(OBSScene scene, bool force)
 {
 	obs_source_t *source = obs_scene_get_source(scene);
 	TransitionToScene(source, force);
@@ -237,7 +237,7 @@ void OBSBasic::TransitionStopped()
 	swapScene = nullptr;
 }
 
-void OBSBasic::TransitionToScene(obs_source_t *source, bool force)
+void OBSBasic::TransitionToScene(OBSSource source, bool force)
 {
 	obs_scene_t *scene = obs_scene_from_source(source);
 	bool usingPreviewProgram = IsPreviewProgramMode();
@@ -293,7 +293,7 @@ static inline void SetComboTransition(QComboBox *combo, obs_source_t *tr)
 	}
 }
 
-void OBSBasic::SetTransition(obs_source_t *transition)
+void OBSBasic::SetTransition(OBSSource transition)
 {
 	obs_source_t *oldTransition = obs_get_output_source(0);
 
@@ -530,7 +530,7 @@ static T GetOBSRef(QListWidgetItem *item)
 	return item->data(static_cast<int>(QtDataRole::OBSRef)).value<T>();
 }
 
-void OBSBasic::SetCurrentScene(obs_source_t *scene, bool force)
+void OBSBasic::SetCurrentScene(OBSSource scene, bool force)
 {
 	if (!IsPreviewProgramMode()) {
 		TransitionToScene(scene, force);

UI/window-basic-main.hpp

@@ -232,10 +232,7 @@ private:
 
 	void InitDefaultTransitions();
 	void InitTransition(obs_source_t *transition);
-	void TransitionToScene(obs_scene_t *scene, bool force = false);
-	void TransitionToScene(obs_source_t *scene, bool force = false);
 	obs_source_t *FindTransition(const char *name);
-	void SetTransition(obs_source_t *transition);
 	OBSSource GetCurrentTransition();
 	obs_data_array_t *SaveTransitions();
 	void LoadTransitions(obs_data_array_t *transitions);
@@ -265,7 +262,6 @@ private:
 	void SetPreviewProgramMode(bool enabled);
 	void ResizeProgram(uint32_t cx, uint32_t cy);
 	void SetCurrentScene(obs_scene_t *scene, bool force = false);
-	void SetCurrentScene(obs_source_t *scene, bool force = false);
 	static void RenderProgram(void *data, uint32_t cx, uint32_t cy);
 
 	std::vector<QuickTransition> quickTransitions;
@@ -316,6 +312,11 @@ public slots:
 	void SaveProjectDeferred();
 	void SaveProject();
 
+	void SetTransition(OBSSource transition);
+	void TransitionToScene(OBSScene scene, bool force = false);
+	void TransitionToScene(OBSSource scene, bool force = false);
+	void SetCurrentScene(OBSSource scene, bool force = false);
+
 private slots:
 	void AddSceneItem(OBSSceneItem item);
 	void RemoveSceneItem(OBSSceneItem item);