From 792bb65e9e2e228c099e67d81fa58ab0f653fae0 Mon Sep 17 00:00:00 2001
From: GenericHeroGuy <genericheroguy@noreply.codeberg.org>
Date: Mon, 21 Jul 2025 18:12:07 +0200
Subject: [PATCH] Add compat for old P_SetScale behavior, fixes Malicious
 Metropolis

---
 src/lua_baselib.c |  2 +-
 src/lua_mobjlib.c |  4 ++--
 src/p_mobj.c      | 14 +++++++++++---
 src/p_mobj.h      |  3 ++-
 4 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/lua_baselib.c b/src/lua_baselib.c
index c0506afff..19110cf5f 100644
--- a/src/lua_baselib.c
+++ b/src/lua_baselib.c
@@ -970,7 +970,7 @@ static int lib_pSetScale(lua_State *L)
 		return LUA_ErrInvalid(L, "mobj_t");
 	if (newscale < FRACUNIT/100)
 		newscale = FRACUNIT/100;
-	P_SetScale(mobj, newscale);
+	P_SetScale2(mobj, newscale, lua_compatmode);
 	return 0;
 }
 
diff --git a/src/lua_mobjlib.c b/src/lua_mobjlib.c
index 5811dba0b..2c1412683 100644
--- a/src/lua_mobjlib.c
+++ b/src/lua_mobjlib.c
@@ -897,7 +897,7 @@ static int mobj_set(lua_State *L)
 			return luaL_error(L, "mobj.type %d out of range (0 - %d).", newtype, NUMMOBJTYPES-1);
 		mo->type = newtype;
 		mo->info = &mobjinfo[newtype];
-		P_SetScale(mo, mo->scale);
+		P_SetScale2(mo, mo->scale, lua_compatmode);
 		break;
 	}
 	case mobj_info:
@@ -972,7 +972,7 @@ static int mobj_set(lua_State *L)
 		if (scale < FRACUNIT/100)
 			scale = FRACUNIT/100;
 		mo->destscale = scale;
-		P_SetScale(mo, scale);
+		P_SetScale2(mo, scale, lua_compatmode);
 		mo->old_scale = scale;
 		break;
 	}
diff --git a/src/p_mobj.c b/src/p_mobj.c
index b80cfdaa9..0fabc21d6 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -6165,7 +6165,7 @@ void P_SpawnParaloop(fixed_t x, fixed_t y, fixed_t z, fixed_t radius, INT32 numb
 //
 // Sets the sprite scaling
 //
-void P_SetScale(mobj_t *mobj, fixed_t newscale)
+void P_SetScale2(mobj_t *mobj, fixed_t newscale, boolean compat)
 {
 	player_t *player;
 	fixed_t oldscale;
@@ -6177,8 +6177,16 @@ void P_SetScale(mobj_t *mobj, fixed_t newscale)
 
 	mobj->scale = newscale;
 
-	mobj->radius = FixedMul(FixedDiv(mobj->radius, oldscale), newscale);
-	mobj->height = FixedMul(FixedDiv(mobj->height, oldscale), newscale);
+	if (compat)
+	{
+		mobj->radius = FixedMul(mobj->info->radius, newscale);
+		mobj->height = FixedMul(mobj->info->height, newscale);
+	}
+	else
+	{
+		mobj->radius = FixedMul(FixedDiv(mobj->radius, oldscale), newscale);
+		mobj->height = FixedMul(FixedDiv(mobj->height, oldscale), newscale);
+	}
 
 	player = mobj->player;
 
diff --git a/src/p_mobj.h b/src/p_mobj.h
index 1329b8da9..d17a38772 100644
--- a/src/p_mobj.h
+++ b/src/p_mobj.h
@@ -566,7 +566,8 @@ boolean P_SupermanLook4Players(mobj_t *actor);
 boolean P_PrecipThinker(precipmobj_t *mobj);
 void P_NullPrecipThinker(precipmobj_t *mobj);
 void P_FreePrecipMobj(precipmobj_t *mobj);
-void P_SetScale(mobj_t *mobj, fixed_t newscale);
+#define P_SetScale(mobj, newscale) P_SetScale2(mobj, newscale, false)
+void P_SetScale2(mobj_t *mobj, fixed_t newscale, boolean compat);
 void P_XYMovement(mobj_t *mo);
 void P_RingXYMovement(mobj_t *mo);
 void P_SceneryXYMovement(mobj_t *mo);