From 59b567689a8cc971c43e513fc5ae5a692516b441 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Tue, 1 Oct 2024 16:38:14 +0200
Subject: [PATCH] make the broken ID24 levelnums work somehow so that Legacy of
 Rust's intermissions play.

---
 src/gamedata/g_mapinfo.cpp |  4 ++++
 src/gamedata/g_mapinfo.h   |  1 +
 src/gamedata/umapinfo.cpp  | 14 ++++++++++----
 src/wi_stuff.cpp           |  4 ++--
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/gamedata/g_mapinfo.cpp b/src/gamedata/g_mapinfo.cpp
index 6cd4fdcdf5..eb65e69433 100644
--- a/src/gamedata/g_mapinfo.cpp
+++ b/src/gamedata/g_mapinfo.cpp
@@ -2401,9 +2401,13 @@ static void SetLevelNum (level_info_t *info, int num)
 	for (unsigned int i = 0; i < wadlevelinfos.Size(); ++i)
 	{
 		if (wadlevelinfos[i].levelnum == num)
+		{
 			wadlevelinfos[i].levelnum = 0;
+			wadlevelinfos[i].broken_id24_levelnum = 0;
+		}
 	}
 	info->levelnum = num;
+	info->broken_id24_levelnum = num;	// at least make it work - somehow.
 }
 
 //==========================================================================
diff --git a/src/gamedata/g_mapinfo.h b/src/gamedata/g_mapinfo.h
index b07e6e442f..8b2706ed06 100644
--- a/src/gamedata/g_mapinfo.h
+++ b/src/gamedata/g_mapinfo.h
@@ -324,6 +324,7 @@ struct FExitText
 struct level_info_t
 {
 	int			levelnum;
+	int			broken_id24_levelnum;
 	
 	FString		MapName;
 	FString		NextMap;
diff --git a/src/gamedata/umapinfo.cpp b/src/gamedata/umapinfo.cpp
index 50757e7343..d6a2c47ee8 100644
--- a/src/gamedata/umapinfo.cpp
+++ b/src/gamedata/umapinfo.cpp
@@ -58,6 +58,7 @@ struct UMapEntry
 	char intermusic[9] = "";
 	int partime = 0;
 	int nointermission = 0;
+	int id24_levelnum = 0;	// note that this one's semantics are massively screwed up. Only to be used for ID24-style intermissions.
 };
 
 static TArray<UMapEntry> Maps;
@@ -124,7 +125,7 @@ static int ParseLumpName(FScanner &scanner, char *buffer)
 //
 // -----------------------------------------------
 
-static int ParseStandardProperty(FScanner &scanner, UMapEntry *mape)
+static int ParseStandardProperty(FScanner &scanner, UMapEntry *mape, int *id24_levelnum)
 {
 	// find the next line with content.
 	// this line is no property.
@@ -254,6 +255,7 @@ static int ParseStandardProperty(FScanner &scanner, UMapEntry *mape)
 			epi.mEpisodeMap = mape->MapName;
 			epi.mPicName = split[0];
 			epi.mNoSkill = false;
+			mape->id24_levelnum = *id24_levelnum = 1;
 
 			unsigned i;
 			for (i = 0; i < AllEpisodes.Size(); i++)
@@ -324,15 +326,16 @@ static int ParseStandardProperty(FScanner &scanner, UMapEntry *mape)
 //
 // -----------------------------------------------
 
-static int ParseMapEntry(FScanner &scanner, UMapEntry *val)
+static int ParseMapEntry(FScanner &scanner, UMapEntry *val, int *id24_levelnum)
 {
 	scanner.MustGetToken(TK_Identifier);
 
 	val->MapName = scanner.String;
+	val->id24_levelnum = ++(*id24_levelnum);
 	scanner.MustGetToken('{');
 	while(!scanner.CheckToken('}'))
 	{
-		ParseStandardProperty(scanner, val);
+		ParseStandardProperty(scanner, val, id24_levelnum);
 	}
 	return 1;
 }
@@ -348,12 +351,13 @@ int ParseUMapInfo(int lumpnum)
 	FScanner scanner(lumpnum);
 	unsigned int i;
 
+	int id24_levelnum = 1;
 	while (scanner.GetToken())
 	{
 		scanner.TokenMustBe(TK_Map);
 
 		UMapEntry parsed;
-		ParseMapEntry(scanner, &parsed);
+		ParseMapEntry(scanner, &parsed, &id24_levelnum);
 
 		// Endpic overrides level exits.
 		if (parsed.endpic[0])
@@ -455,6 +459,8 @@ void CommitUMapinfo(level_info_t *defaultinfo)
 		if (map.exitpic[0]) levelinfo->ExitPic = map.exitpic;
 		if (map.enteranim[0]) levelinfo->EnterAnim = map.enteranim;
 		if (map.exitanim[0]) levelinfo->ExitAnim = map.exitanim;
+		levelinfo->broken_id24_levelnum = map.id24_levelnum;
+		Printf("%s: id24 levelnum = %d\n", map.MapName, map.id24_levelnum);
 		/* UMAPINFO's intermusic is for the text screen, not the summary.
 		if (map.intermusic[0])
 		{
diff --git a/src/wi_stuff.cpp b/src/wi_stuff.cpp
index 8a5c7945cc..3af0a7829a 100644
--- a/src/wi_stuff.cpp
+++ b/src/wi_stuff.cpp
@@ -302,7 +302,7 @@ private:
 					auto* li = FindLevelInfo(state != StatCount ? wbs->next.GetChars() : wbs->current.GetChars());
 					if (!li)
 						return false;
-					if (li->levelnum != condition.param)
+					if (li->broken_id24_levelnum != condition.param)
 						return false;
 					break;
 				}
@@ -311,7 +311,7 @@ private:
 					auto* li = FindLevelInfo(state != StatCount ? wbs->next.GetChars() : wbs->current.GetChars());
 					if (!li)
 						return false;
-					if (li->levelnum <= condition.param)
+					if (li->broken_id24_levelnum <= condition.param)
 						return false;
 					break;
 				}