- added compatibility flag for buggy CheckSwitchRange behavior

https://forum.zdoom.org/viewtopic.php?t=63008
https://forum.zdoom.org/viewtopic.php?t=63650

src/d_main.cpp

@@ -600,7 +600,7 @@ CUSTOM_CVAR(Int, compatmode, 0, CVAR_ARCHIVE|CVAR_NOINITCALL)
 
 	case 4: // Old ZDoom compat mode
 		v = COMPATF_SOUNDTARGET | COMPATF_LIGHT;
-		w = COMPATF2_MULTIEXIT | COMPATF2_TELEPORT | COMPATF2_PUSHWINDOW;
+		w = COMPATF2_MULTIEXIT | COMPATF2_TELEPORT | COMPATF2_PUSHWINDOW | COMPATF2_CHECKSWITCHRANGE;
 		break;
 
 	case 5: // MBF compat mode
@@ -658,6 +658,7 @@ CVAR (Flag, compat_pointonline,			compatflags2, COMPATF2_POINTONLINE);
 CVAR (Flag, compat_multiexit,			compatflags2, COMPATF2_MULTIEXIT);
 CVAR (Flag, compat_teleport,			compatflags2, COMPATF2_TELEPORT);
 CVAR (Flag, compat_pushwindow,			compatflags2, COMPATF2_PUSHWINDOW);
+CVAR (Flag, compat_checkswitchrange,	compatflags2, COMPATF2_CHECKSWITCHRANGE);
 
 CVAR(Bool, vid_activeinbackground, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 

src/doomdef.h

@@ -328,6 +328,7 @@ enum : unsigned int
 	COMPATF2_MULTIEXIT		= 1 << 4,	// Level exit can be triggered multiple times (required by Daedalus's travel tubes, thanks to a faulty script)
 	COMPATF2_TELEPORT		= 1 << 5,	// Don't let indirect teleports trigger sector actions
 	COMPATF2_PUSHWINDOW		= 1 << 6,	// Disable the window check in CheckForPushSpecial()
+	COMPATF2_CHECKSWITCHRANGE = 1 << 7,	// Enable buggy CheckSwitchRange behavior
 };
 
 // Emulate old bugs for select maps. These are not exposed by a cvar

src/g_shared/p_switch.cpp

@@ -194,7 +194,9 @@ bool P_CheckSwitchRange(AActor *user, line_t *line, int sideno, const DVector3 *
 			}
 		}
 
-		return (user->Top() > open.top);
+		return (user->Level->i_compatflags2 & COMPATF2_CHECKSWITCHRANGE)
+			? (user->Top() >= open.top)
+			: (user->Top() > open.top);
 	}
 	else if ((TexMan.FindSwitch(side->GetTexture(side_t::bottom))) != NULL)
 	{
@@ -216,7 +218,9 @@ bool P_CheckSwitchRange(AActor *user, line_t *line, int sideno, const DVector3 *
 			}
 		}
 
-		return (user->Z() < open.bottom);
+		return (user->Level->i_compatflags2 & COMPATF2_CHECKSWITCHRANGE)
+			? (user->Z() <= open.bottom)
+			: (user->Z() < open.bottom);
 	}
 	else if ((flags & ML_3DMIDTEX) || (TexMan.FindSwitch(side->GetTexture(side_t::mid))) != NULL)
 	{
@@ -229,7 +233,9 @@ bool P_CheckSwitchRange(AActor *user, line_t *line, int sideno, const DVector3 *
 	else
 	{
 		// no switch found. Check whether the player can touch either top or bottom texture
-		return (user->Top() > open.top) || (user->isBelow(open.bottom));
+		return (user->Level->i_compatflags2 & COMPATF2_CHECKSWITCHRANGE)
+			? ( (user->Top() >= open.top) || (user->Z() <= open.bottom) )
+			: ( (user->Top() > open.top)  || user->isBelow(open.bottom) );
 	}
 }
 

src/gamedata/g_mapinfo.cpp

@@ -1619,6 +1619,7 @@ MapFlagHandlers[] =
 	{ "compat_multiexit",				MITYPE_COMPATFLAG, 0, COMPATF2_MULTIEXIT },
 	{ "compat_teleport",				MITYPE_COMPATFLAG, 0, COMPATF2_TELEPORT },
 	{ "compat_pushwindow",				MITYPE_COMPATFLAG, 0, COMPATF2_PUSHWINDOW },
+	{ "compat_checkswitchrange",		MITYPE_COMPATFLAG, 0, COMPATF2_CHECKSWITCHRANGE },
 	{ "cd_start_track",					MITYPE_EATNEXT,	0, 0 },
 	{ "cd_end1_track",					MITYPE_EATNEXT,	0, 0 },
 	{ "cd_end2_track",					MITYPE_EATNEXT,	0, 0 },

src/maploader/compatibility.cpp

@@ -164,6 +164,7 @@ static FCompatOption Options[] =
 	{ "multiexit",				COMPATF2_MULTIEXIT, SLOT_COMPAT2 },
 	{ "teleport",				COMPATF2_TELEPORT, SLOT_COMPAT2 },
 	{ "disablepushwindowcheck",	COMPATF2_PUSHWINDOW, SLOT_COMPAT2 },
+	{ "checkswitchrange",		COMPATF2_CHECKSWITCHRANGE, SLOT_COMPAT2 },
 	{ NULL, 0, 0 }
 };
 

wadsrc/static/language.enu

@@ -2184,6 +2184,7 @@ CMPTMNU_SOUNDCUTOFF			= "Sounds stop when actor vanishes";
 CMPTMNU_SOUNDTARGET			= "Use original sound target handling";
 CMPTMNU_TELEPORT			= "Scripted teleports don't trigger sector actions";
 CMPTMNU_PUSHWINDOW			= "Non-blocking lines can be pushed";
+CMPTMNU_CHECKSWITCHRANGE	= "Enable buggy CheckSwitchRange behavior";
 
 // Sound Options
 SNDMNU_TITLE			= "SOUND OPTIONS";

wadsrc/static/menudef.txt

@@ -1434,6 +1434,7 @@ OptionMenu "CompatibilityOptions" protected
 	Option "$CMPTMNU_MULTIEXIT",					"compat_multiexit", "YesNo"
 	Option "$CMPTMNU_TELEPORT",						"compat_teleport", "YesNo"
 	Option "$CMPTMNU_PUSHWINDOW",					"compat_pushwindow", "YesNo"
+	Option "$CMPTMNU_CHECKSWITCHRANGE",				"compat_checkswitchrange", "YesNo"
 
 	StaticText " "
 	StaticText "$CMPTMNU_PHYSICSBEHAVIOR",1

wadsrc/static/zscript/constants.txt

@@ -1338,4 +1338,5 @@ enum ECompatFlags
 	COMPATF2_MULTIEXIT		= 1 << 4,	// Level exit can be triggered multiple times (required by Daedalus's travel tubes, thanks to a faulty script)
 	COMPATF2_TELEPORT		= 1 << 5,	// Don't let indirect teleports trigger sector actions
 	COMPATF2_PUSHWINDOW		= 1 << 6,	// Disable the window check in CheckForPushSpecial()
+	COMPATF2_CHECKSWITCHRANGE = 1 << 7,	// Enable buggy CheckSwitchRange behavior
 };