diff --git a/src/doomdef.h b/src/doomdef.h
index 1c034f5f7..593ad0358 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -538,4 +538,7 @@ extern const char *compdate, *comptime, *comprevision, *compbranch;
 ///      	SRB2CB itself ported this from PrBoom+
 #define NEWCLIP
 
+/// Cache patches in Lua more safely, so that renderer switching can work.
+#define LUA_PATCH_SAFETY
+
 #endif // __DOOMDEF__
diff --git a/src/lua_hudlib.c b/src/lua_hudlib.c
index ba8b3a6d9..5e104c77a 100644
--- a/src/lua_hudlib.c
+++ b/src/lua_hudlib.c
@@ -34,6 +34,11 @@ static UINT8 hud_enabled[(hud_MAX/8)+1];
 
 static UINT8 hudAvailable; // hud hooks field
 
+#ifdef LUA_PATCH_SAFETY
+static patchinfo_t *patchinfo, *patchinfohead;
+static int numluapatches;
+#endif
+
 // must match enum hud in lua_hud.h
 static const char *const hud_disable_options[] = {
 	"stagetitle",
@@ -231,12 +236,17 @@ static int colormap_get(lua_State *L)
 
 static int patch_get(lua_State *L)
 {
+#ifdef LUA_PATCH_SAFETY
 	patch_t *patch = *((patch_t **)luaL_checkudata(L, 1, META_PATCH));
+#else
+	patchinfo_t *patch = *((patchinfo_t **)luaL_checkudata(L, 1, META_PATCH));
+#endif
 	enum patch field = luaL_checkoption(L, 2, NULL, patch_opt);
 
 	// patches are CURRENTLY always valid, expected to be cached with PU_STATIC
 	// this may change in the future, so patch.valid still exists
-	I_Assert(patch != NULL);
+	if (!patch)
+		return LUA_ErrInvalid(L, "patch_t");
 
 	switch (field)
 	{
@@ -333,8 +343,59 @@ static int libd_patchExists(lua_State *L)
 
 static int libd_cachePatch(lua_State *L)
 {
+#ifdef LUA_PATCH_SAFETY
+	int i;
+	lumpnum_t lumpnum;
+	patchinfo_t *luapat;
+	patch_t *realpatch;
+
+	HUDONLY
+
+	luapat = patchinfohead;
+	lumpnum = W_CheckNumForName(luaL_checkstring(L, 1));
+	if (lumpnum == LUMPERROR)
+		lumpnum = W_GetNumForName("MISSING");
+
+	for (i = 0; i < numluapatches; i++)
+	{
+		// check if already cached
+		if (luapat->wadnum == WADFILENUM(lumpnum) && luapat->lumpnum == LUMPNUM(lumpnum))
+		{
+			LUA_PushUserdata(L, luapat, META_PATCH);
+			return 1;
+		}
+		luapat = luapat->next;
+		if (!luapat)
+			break;
+	}
+
+	if (numluapatches > 0)
+	{
+		patchinfo->next = Z_Malloc(sizeof(patchinfo_t), PU_STATIC, NULL);
+		patchinfo = patchinfo->next;
+	}
+	else
+	{
+		patchinfo = Z_Malloc(sizeof(patchinfo_t), PU_STATIC, NULL);
+		patchinfohead = patchinfo;
+	}
+
+	realpatch = W_CachePatchNum(lumpnum, PU_PATCH);
+
+	patchinfo->width = realpatch->width;
+	patchinfo->height = realpatch->height;
+	patchinfo->leftoffset = realpatch->leftoffset;
+	patchinfo->topoffset = realpatch->topoffset;
+
+	patchinfo->wadnum = WADFILENUM(lumpnum);
+	patchinfo->lumpnum = LUMPNUM(lumpnum);
+
+	LUA_PushUserdata(L, patchinfo, META_PATCH);
+	numluapatches++;
+#else
 	HUDONLY
 	LUA_PushUserdata(L, W_CachePatchName(luaL_checkstring(L, 1), PU_PATCH), META_PATCH);
+#endif
 	return 1;
 }
 
@@ -342,12 +403,22 @@ static int libd_draw(lua_State *L)
 {
 	INT32 x, y, flags;
 	patch_t *patch;
+#ifdef LUA_PATCH_SAFETY
+	patchinfo_t *luapat;
+#endif
 	const UINT8 *colormap = NULL;
 
 	HUDONLY
 	x = luaL_checkinteger(L, 1);
 	y = luaL_checkinteger(L, 2);
+#ifdef LUA_PATCH_SAFETY
+	luapat = *((patchinfo_t **)luaL_checkudata(L, 3, META_PATCH));
+	patch = W_CachePatchNum((luapat->wadnum<<16)+luapat->lumpnum, PU_PATCH);
+#else
 	patch = *((patch_t **)luaL_checkudata(L, 3, META_PATCH));
+	if (!patch)
+		return LUA_ErrInvalid(L, "patch_t");
+#endif
 	flags = luaL_optinteger(L, 4, 0);
 	if (!lua_isnoneornil(L, 5))
 		colormap = *((UINT8 **)luaL_checkudata(L, 5, META_COLORMAP));
@@ -363,6 +434,9 @@ static int libd_drawScaled(lua_State *L)
 	fixed_t x, y, scale;
 	INT32 flags;
 	patch_t *patch;
+#ifdef LUA_PATCH_SAFETY
+	patchinfo_t *luapat;
+#endif
 	const UINT8 *colormap = NULL;
 
 	HUDONLY
@@ -371,7 +445,14 @@ static int libd_drawScaled(lua_State *L)
 	scale = luaL_checkinteger(L, 3);
 	if (scale < 0)
 		return luaL_error(L, "negative scale");
+#ifdef LUA_PATCH_SAFETY
+	luapat = *((patchinfo_t **)luaL_checkudata(L, 4, META_PATCH));
+	patch = W_CachePatchNum((luapat->wadnum<<16)+luapat->lumpnum, PU_PATCH);
+#else
 	patch = *((patch_t **)luaL_checkudata(L, 4, META_PATCH));
+	if (!patch)
+		return LUA_ErrInvalid(L, "patch_t");
+#endif
 	flags = luaL_optinteger(L, 5, 0);
 	if (!lua_isnoneornil(L, 6))
 		colormap = *((UINT8 **)luaL_checkudata(L, 6, META_COLORMAP));
@@ -659,6 +740,10 @@ int LUA_HudLib(lua_State *L)
 {
 	memset(hud_enabled, 0xff, (hud_MAX/8)+1);
 
+#ifdef LUA_PATCH_SAFETY
+	numluapatches = 0;
+#endif
+
 	lua_newtable(L); // HUD registry table
 		lua_newtable(L);
 		luaL_register(L, NULL, lib_draw);
diff --git a/src/r_defs.h b/src/r_defs.h
index 1cb4e0815..c09635bd5 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -726,6 +726,24 @@ typedef struct
 #pragma pack()
 #endif
 
+// Same as a patch_t, except just the header
+// and the wadnum/lumpnum combination that points
+// to wherever the patch is in memory.
+struct patchinfo_s
+{
+	INT16 width;          // bounding box size
+	INT16 height;
+	INT16 leftoffset;     // pixels to the left of origin
+	INT16 topoffset;      // pixels below the origin
+
+	UINT16 wadnum;        // the software patch lump num for when the patch
+	UINT16 lumpnum;       // was flushed, and we need to re-create it
+
+	// next patchinfo_t in memory
+	struct patchinfo_s *next;
+};
+typedef struct patchinfo_s patchinfo_t;
+
 //
 // Sprites are patches with a special naming convention so they can be
 //  recognized by R_InitSprites.