additional music checks

This adds several fixes to make the event and menu music more robust:
1. The game will now run with zero soundtracks.  All accesses into a potentially empty vector should now have checks.
2. Soundtracks and menu music are now checked for validity before being played (not just when importing a FSM mission).
3. The parsing validity checks and the in-game event music now check for skippable patterns using the same function.
4. Zero measures and zero samples-per-measure now cause the game to skip a pattern.  Negative values now trigger a warning.
5. Omitting some or all of the `$Name:` lines for a soundtrack will not cause an assert.

Fixes #5576.  Follow-up to #5572.

code/gamesnd/eventmusic.cpp

@@ -257,6 +257,19 @@ SCP_vector<menu_music> Spooled_music;
 int Mission_music[NUM_SCORES];
 
 
+bool event_music_pattern_is_skippable(const SOUNDTRACK_PATTERN_INFO &pattern)
+{
+	// check for blank or "none"
+	if (pattern.fname[0] == '\0' || !strnicmp(pattern.fname, NOX("none.wav"), 4))
+		return true;
+
+	// no content means this pattern isn't intended to play
+	if (pattern.num_measures == 0 || pattern.samples_per_measure == 0)
+		return true;
+
+	return false;
+}
+
 // -------------------------------------------------------------------------------------------------
 // event_music_init() 
 //
@@ -294,7 +307,7 @@ void event_music_init()
 	// now that we've parsed everything, check the validity
 	for (auto &soundtrack : Soundtracks)
 	{
-		bool all_patterns_found = true;
+		bool all_patterns_valid = true;
 
 		// Goober5000 - set the valid flag according to whether we can load all our patterns
 		// (since someone may be running an enhanced music.tbl without warble_fs1 installed)
@@ -302,10 +315,18 @@ void event_music_init()
 		{
 			auto filename = soundtrack.patterns[i].fname;
 
-			// check for "none"
-			if (!strlen(filename) || !strnicmp(filename, "none", 4))
+			// some patterns aren't played for various legitimate reasons
+			if (event_music_pattern_is_skippable(soundtrack.patterns[i]))
 				continue;
 
+			// check for negative numbers (zero is allowed)
+			if (soundtrack.patterns[i].num_measures < 0 || soundtrack.patterns[i].samples_per_measure < 0)
+			{
+				Warning(LOCATION, "Soundtrack file %s has a negative 'num_measures' or 'samples_per_measure'; this is not allowed", soundtrack.patterns[i].fname);
+				all_patterns_valid = false;
+				break;
+			}
+
 			// check for file with exact extension
 			// (since event music specifies samples and measures, the audio format is important; so we don't want to assume any format will work)
 			if (!cf_exists_full(filename, CF_TYPE_MUSIC))
@@ -318,12 +339,12 @@ void event_music_init()
 #endif
 
 				Warning(LOCATION, "One or more files in '%s' could not be loaded.  The soundtrack will not be used.", soundtrack.name);
-				all_patterns_found = false;
+				all_patterns_valid = false;
 				break;
 			}
 		}
 
-		if (all_patterns_found)
+		if (all_patterns_valid)
 			soundtrack.flags |= EMF_VALID;
 	}
 	
@@ -581,14 +602,11 @@ void event_music_level_start(int force_soundtrack)
 	if (force_soundtrack != -1)
 		Current_soundtrack_num = force_soundtrack;
 
+	// Check that soundtrack index is in range, except that < 0 means no soundtrack
 	if (Current_soundtrack_num < 0)
-	{
 		return;
-	}
-
-	Assert(Current_soundtrack_num >= 0 && Current_soundtrack_num < (int)Soundtracks.size());
-
-	if (Current_soundtrack_num < 0 || Current_soundtrack_num > (int)Soundtracks.size())
+	Assert(Current_soundtrack_num < (int)Soundtracks.size());
+	if (Current_soundtrack_num >= (int)Soundtracks.size())
 		return;
 
 	strack = &Soundtracks[Current_soundtrack_num];
@@ -601,7 +619,7 @@ void event_music_level_start(int force_soundtrack)
 	// tracks because their patterns weren't -1
 	for (i = 0; i < MAX_PATTERNS; i++)
 	{
-		if (!strnicmp(strack->patterns[i].fname, NOX("none.wav"), 4))
+		if (event_music_pattern_is_skippable(strack->patterns[i]))
 		{
 			Patterns[i].handle = -1;
 			continue;
@@ -1203,9 +1221,6 @@ void parse_soundtrack()
 	int i, strack_idx = -1;
 	bool nocreate = false;
 
-	//Start parsing soundtrack
-	//required_string("#Soundtrack Start");
-
 	//Get the name, and do we have this track already?
 	required_string("$SoundTrack Name:");
 	stuff_string(namebuf, F_NAME, NAME_LENGTH);
@@ -1599,7 +1614,7 @@ int hostile_ships_present()
 // NOTE: callers to this function are advised to allocate a 256 byte buffer
 void event_music_get_info(char *outbuf)
 {
-	if ( Event_music_enabled == FALSE || Event_music_level_inited == FALSE || Current_pattern == -1 ) {
+	if ( Event_music_enabled == FALSE || Event_music_level_inited == FALSE || Current_soundtrack_num < 0 || Current_pattern < 0 ) {
 		strcpy(outbuf,XSTR( "Event music is not playing", 213));
 	}
 	else {	
@@ -1618,7 +1633,7 @@ int event_music_next_soundtrack(int delta)
 {
 	int new_soundtrack;
 
-	if ( Event_music_enabled == FALSE || Event_music_level_inited == FALSE ) {
+	if ( Event_music_enabled == FALSE || Event_music_level_inited == FALSE || Soundtracks.empty() ) {
 		return -1;
 	}
 		
@@ -1662,7 +1677,7 @@ void event_sexp_change_soundtrack(const char *name)
 // NOTE: callers to this function are advised to allocate a NAME_LENGTH buffer
 void event_music_get_soundtrack_name(char *outbuf)
 {
-	if ( Event_music_enabled == FALSE || Event_music_level_inited == FALSE ) {
+	if ( Event_music_enabled == FALSE || Event_music_level_inited == FALSE || Current_soundtrack_num < 0 ) {
 		strcpy(outbuf, XSTR( "Event music is not playing", 213));
 	}
 	else {
@@ -1673,11 +1688,15 @@ void event_music_get_soundtrack_name(char *outbuf)
 // set the current soundtrack based on name
 void event_music_set_soundtrack(const char *name)
 {
-	Current_soundtrack_num = event_music_get_soundtrack_index(name);
+	int index = event_music_get_soundtrack_index(name);
 
-	if ( Current_soundtrack_num == -1 ) {
+	if (index >= 0 && Soundtracks[index].flags & EMF_VALID)
+		Current_soundtrack_num = index;
+	else
+		Current_soundtrack_num = -1;
+
+	if (Current_soundtrack_num == -1)
 		mprintf(("Current soundtrack set to -1 in event_music_set_soundtrack\n"));
-	}
 }
 
 int event_music_get_soundtrack_index(const char *name)
@@ -1694,7 +1713,7 @@ int event_music_get_soundtrack_index(const char *name)
 
 int event_music_get_spooled_music_index(const char *name)
 {
-	// find the correct index for the event music
+	// find the correct index for the spooled music
 	for ( int i = 0; i < (int)Spooled_music.size(); i++ ) {
 		if ( !stricmp(name, Spooled_music[i].name) ) {
 			return i;
@@ -1714,8 +1733,12 @@ void event_music_set_score(int score_index, const char *name)
 {
 	Assert(score_index < NUM_SCORES);
 
-	// find the correct index for the event music
-	Mission_music[score_index] = event_music_get_spooled_music_index(name);
+	int index = event_music_get_spooled_music_index(name);
+
+	if (index >= 0 && Spooled_music[index].flags & SMF_VALID)
+		Mission_music[score_index] = index;
+	else
+		Mission_music[score_index] = -1;
 }
 
 // reset what sort of music is to be used for this mission

code/gamesnd/eventmusic.h

@@ -74,15 +74,16 @@ extern SCP_vector<menu_music> Spooled_music;
 
 
 // event music soundtrack storage
+typedef struct tagSOUNDTRACK_PATTERN_INFO {
+	char fname[MAX_FILENAME_LEN];
+	float num_measures;
+	int samples_per_measure;
+} SOUNDTRACK_PATTERN_INFO;
 typedef struct tagSOUNDTRACK_INFO {
 	int flags;
 	int	num_patterns;
 	char name[NAME_LENGTH];
-	struct {
-		char fname[MAX_FILENAME_LEN];
-		float num_measures;
-		int samples_per_measure;
-	} patterns[MAX_PATTERNS];
+	SOUNDTRACK_PATTERN_INFO patterns[MAX_PATTERNS];
 } SOUNDTRACK_INFO;
 
 // Goober5000 - event music flags

code/mission/missionparse.cpp

@@ -1126,7 +1126,7 @@ void parse_briefing_info(mission * /*pm*/)
  */
 void parse_music(mission *pm, int flags)
 {
-	int index, num;
+	int index;
 	char *ch;
 	char temp[NAME_LENGTH];
 
@@ -1233,9 +1233,12 @@ void parse_music(mission *pm, int flags)
 			}
 		}
 
-		// last resort: pick a random track out of the 7 FS2 soundtracks
-		num = std::max((int)Soundtracks.size(), 7);
-		strcpy_s(pm->event_music_name, Soundtracks[Random::next(num)].name);
+		if (!Soundtracks.empty())
+		{
+			// last resort: pick a random track out of the 7 FS2 soundtracks
+			int num = std::max((int)Soundtracks.size(), 7);
+			strcpy_s(pm->event_music_name, Soundtracks[Random::next(num)].name);
+		}
 
 
 done_event_music:
@@ -1260,9 +1263,12 @@ done_event_music:
 		if (event_music_get_spooled_music_index(pm->briefing_music_name) >= 0)
 			goto done_briefing_music;
 
-		// last resort: pick a random track out of the first 7 FS2 briefings (the regular ones)...
-		num = std::max((int)Spooled_music.size(), 7);
-		strcpy_s(pm->briefing_music_name, Spooled_music[Random::next(num)].name);
+		if (!Spooled_music.empty())
+		{
+			// last resort: pick a random track out of the first 7 FS2 briefings (the regular ones)...
+			int num = std::max((int)Spooled_music.size(), 7);
+			strcpy_s(pm->briefing_music_name, Spooled_music[Random::next(num)].name);
+		}
 
 
 done_briefing_music:

code/missionui/missionscreencommon.cpp

@@ -315,10 +315,10 @@ void set_active_ui(UI_WINDOW *ui_window)
 	Active_ui_window = ui_window;
 }
 
-SCP_string common_music_get_filename(int score_index)
+const char *common_music_get_filename(int score_index)
 {
 	if (Cmdline_freespace_no_music) {
-		return SCP_string();
+		return "";
 	}
 
 	Assertion(score_index >= 0 && score_index < NUM_SCORES, "Invalid score index %d.", score_index);
@@ -330,7 +330,7 @@ SCP_string common_music_get_filename(int score_index)
 				"No briefing music is selected, so play first briefing track: %s\n",
 				Spooled_music[Mission_music[score_index]].name));
 		} else {
-			return SCP_string();
+			return "";
 		}
 	}
 
@@ -341,11 +341,11 @@ void common_music_init(int score_index)
 {
 	const auto file_name = common_music_get_filename(score_index);
 
-	if (file_name.empty()) {
+	if (file_name[0] == '\0') {
 		return;
 	}
 
-	briefing_load_music(file_name.c_str());
+	briefing_load_music(file_name);
 	// Use this id to trigger the start of music playing on the briefing screen
 	Briefing_music_begin_timestamp = ui_timestamp(BRIEFING_MUSIC_DELAY);
 }

code/missionui/missionscreencommon.h

@@ -106,15 +106,10 @@ void unload_wing_icons();
 void	common_flash_button_init();
 int	common_flash_bright();
 
-// functions for the multiplayer chat window
-void common_render_chat_window();
-void multi_chat_scroll_up();
-void multi_chat_scroll_down();
-
 void	set_active_ui(UI_WINDOW *ui_window);
 
 // music functions exported for multiplayer team selection screen to start briefing music
-SCP_string common_music_get_filename(int score_index);
+const char *common_music_get_filename(int score_index);
 void common_music_init( int score_index );
 void common_music_do();
 void common_music_close();

code/scripting/api/libs/ui.cpp

@@ -570,7 +570,7 @@ ADE_FUNC(getBriefingMusicName,
 	"string",
 	"The file name or empty if no music")
 {
-	return ade_set_args(L, "s", common_music_get_filename(SCORE_BRIEFING).c_str());
+	return ade_set_args(L, "s", common_music_get_filename(SCORE_BRIEFING));
 }
 
 ADE_FUNC(runBriefingStageHook,
@@ -956,7 +956,7 @@ ADE_FUNC(getDebriefingMusicName,
 	"string",
 	"The file name or empty if no music")
 {
-	return ade_set_args(L, "s", common_music_get_filename(debrief_select_music()).c_str());
+	return ade_set_args(L, "s", common_music_get_filename(debrief_select_music()));
 }
 
 ADE_FUNC(getDebriefing, l_UserInterface_Debrief, nullptr, "Get the debriefing", "debriefing", "The debriefing data")
@@ -1228,7 +1228,7 @@ ADE_FUNC(getFictionMusicName, l_UserInterface_FictionViewer, nullptr,
 	"string",
 	"The file name or empty if no music")
 {
-	return ade_set_args(L, "s", common_music_get_filename(SCORE_FICTION_VIEWER).c_str());
+	return ade_set_args(L, "s", common_music_get_filename(SCORE_FICTION_VIEWER));
 }
 
 //**********SUBLIBRARY: UserInterface/ShipWepSelect