Add metatables to lua vectors (#11039)

Add backwards-compatible metatable functions for vectors.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/script/common/c_converter.cpp b/src/script/common/c_converter.cpp
index c00401b58..d848b75b8 100644
--- a/src/script/common/c_converter.cpp
+++ b/src/script/common/c_converter.cpp
@@ -51,6 +51,29 @@ if (value < F1000_MIN || value > F1000_MAX) { \
 #define CHECK_POS_TAB(index) CHECK_TYPE(index, "position", LUA_TTABLE)
 
 
+/**
+ * A helper which sets (if available) the vector metatable from builtin as metatable
+ * for the table on top of the stack
+ */
+static void set_vector_metatable(lua_State *L)
+{
+	// get vector.metatable
+	lua_getglobal(L, "vector");
+	if (!lua_istable(L, -1)) {
+		// there is no global vector table
+		lua_pop(L, 1);
+		errorstream << "set_vector_metatable in c_converter.cpp: " <<
+				"missing global vector table" << std::endl;
+		return;
+	}
+	lua_getfield(L, -1, "metatable");
+	// set the metatable
+	lua_setmetatable(L, -3);
+	// pop vector global
+	lua_pop(L, 1);
+}
+
+
 void push_float_string(lua_State *L, float value)
 {
 	std::stringstream ss;
@@ -69,6 +92,7 @@ void push_v3f(lua_State *L, v3f p)
 	lua_setfield(L, -2, "y");
 	lua_pushnumber(L, p.Z);
 	lua_setfield(L, -2, "z");
+	set_vector_metatable(L);
 }
 
 void push_v2f(lua_State *L, v2f p)
@@ -281,6 +305,7 @@ void push_v3s16(lua_State *L, v3s16 p)
 	lua_setfield(L, -2, "y");
 	lua_pushinteger(L, p.Z);
 	lua_setfield(L, -2, "z");
+	set_vector_metatable(L);
 }
 
 v3s16 read_v3s16(lua_State *L, int index)