From 04ea28defc85c09e44fbc317d1762f96335842cf Mon Sep 17 00:00:00 2001
From: Rachael Alexanderson <madame-rachelle@users.noreply.github.com>
Date: Mon, 30 Jan 2023 16:45:03 -0500
Subject: [PATCH] - add RedirectCVAR directive for loading alternate maps based
 on a Bool CVAR setting

---
 src/g_level.cpp            |  6 ++++++
 src/gamedata/g_mapinfo.cpp | 32 ++++++++++++++++++++++++++++++++
 src/gamedata/g_mapinfo.h   |  5 +++++
 3 files changed, 43 insertions(+)

diff --git a/src/g_level.cpp b/src/g_level.cpp
index 0a19c44fa..208913566 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -557,6 +557,12 @@ void G_InitNew (const char *mapname, bool bTitleLevel)
 		// [RH] Mark all levels as not visited
 		for (unsigned int i = 0; i < wadlevelinfos.Size(); i++)
 			wadlevelinfos[i].flags = wadlevelinfos[i].flags & ~LEVEL_VISITED;
+
+		auto redirectmap = FindLevelInfo(mapname);
+		if (redirectmap->RedirectCVAR != NAME_None)
+			redirectmap = redirectmap->CheckLevelRedirect();
+		if (redirectmap)
+			mapname = redirectmap->MapName;
 	}
 
 	UnlatchCVars ();
diff --git a/src/gamedata/g_mapinfo.cpp b/src/gamedata/g_mapinfo.cpp
index e2848c015..e85803af6 100644
--- a/src/gamedata/g_mapinfo.cpp
+++ b/src/gamedata/g_mapinfo.cpp
@@ -274,6 +274,8 @@ void level_info_t::Reset()
 	Translator = "";
 	RedirectType = NAME_None;
 	RedirectMapName = "";
+	RedirectCVAR = NAME_None;
+	RedirectCVARMapName = "";
 	EnterPic = "";
 	ExitPic = "";
 	Intermission = NAME_None;
@@ -388,6 +390,27 @@ level_info_t *level_info_t::CheckLevelRedirect ()
 			}
 		}
 	}
+	if (RedirectCVAR != NAME_None)
+	{
+		auto var = FindCVar(RedirectCVAR.GetChars(), NULL);
+		if ((var->GetRealType() == CVAR_Bool) && !(var->GetFlags() & CVAR_IGNORE))	// only check Bool cvars that are currently defined
+		{
+			if (var->GetFlags() & CVAR_USERINFO)
+			{
+				// user sync'd cvar, check for all players
+				for (int i = 0; i < MAXPLAYERS; ++i)
+				{
+					if (playeringame[i] && (var = GetCVar(i, RedirectCVAR.GetChars())))
+					{
+						if (var->ToInt())
+							return FindLevelInfo(RedirectCVARMapName);
+					}
+				}
+			}
+			else if (var->ToInt())
+				return FindLevelInfo(RedirectCVARMapName);
+		}
+	}
 	return NULL;
 }
 
@@ -1299,6 +1322,15 @@ DEFINE_MAP_OPTION(redirect, true)
 	parse.ParseNextMap(info->RedirectMapName);
 }
 
+DEFINE_MAP_OPTION(cvar_redirect, true)
+{
+	parse.ParseAssign();
+	parse.sc.MustGetString();
+	info->RedirectCVAR = parse.sc.String;
+	parse.ParseComma();
+	parse.ParseNextMap(info->RedirectCVARMapName);
+}
+
 DEFINE_MAP_OPTION(sndseq, true)
 {
 	parse.ParseAssign();
diff --git a/src/gamedata/g_mapinfo.h b/src/gamedata/g_mapinfo.h
index 166a53439..f9e97e0c5 100644
--- a/src/gamedata/g_mapinfo.h
+++ b/src/gamedata/g_mapinfo.h
@@ -380,6 +380,11 @@ struct level_info_t
 	FName		RedirectType;
 	FString		RedirectMapName;
 
+	// CVAR Redirection: If the CVAR Bool returns true, then
+	// you go to the RedirectMap instead of this one.
+	FName		RedirectCVAR;
+	FString		RedirectCVARMapName;
+
 	FString		EnterPic;
 	FString		ExitPic;
 	FString 	InterMusic;