libobs: Add obs_source_showing function

This allows the ability to see whether the source is being displayed
somewhere (though not necessarily active in the main output)

libobs/obs-source.c

@@ -2064,6 +2064,11 @@ bool obs_source_active(const obs_source_t *source)
 	return source ? source->activate_refs != 0 : false;
 }
 
+bool obs_source_showing(const obs_source_t *source)
+{
+	return source ? source->show_refs != 0 : false;
+}
+
 static inline void signal_flags_updated(obs_source_t *source)
 {
 	struct calldata data = {0};

libobs/obs.h

@@ -735,6 +735,11 @@ EXPORT void obs_source_enum_tree(obs_source_t *source,
 /** Returns true if active, false if not */
 EXPORT bool obs_source_active(const obs_source_t *source);
 
+/**
+ * Returns true if currently displayed somewhere (active or not), false if not
+ */
+EXPORT bool obs_source_showing(const obs_source_t *source);
+
 /**
  * Sometimes sources need to be told when to save their settings so they
  * don't have to constantly update and keep track of their settings.  This will