Function CreateCallback

engine/script/src/script.cpp:1684–1787

    }

    LuaCallbackInfo* CreateCallback(lua_State* L, int callback_stack_index)
    {
        luaL_checktype(L, callback_stack_index, LUA_TFUNCTION);

        DM_LUA_STACK_CHECK(L, 0);

        GetInstance(L);
        // [-1] instance

        if (!GetMetaFunction(L, -1, META_GET_INSTANCE_CONTEXT_TABLE_REF, sizeof(META_GET_INSTANCE_CONTEXT_TABLE_REF) - 1))
        {
            dmLogError("CreateCallback failed: missing %s meta function for instance context table", "INSTANCE_CONTEXT");
            lua_pop(L, 1);
            return 0x0;
        }
        // [-2] instance
        // [-1] META_GET_INSTANCE_CONTEXT_TABLE_REF()

        lua_pushvalue(L, -2);
        // [-3] instance
        // [-2] META_GET_INSTANCE_CONTEXT_TABLE_REF()
        // [-1] instance

        lua_call(L, 1, 1);
        // [-2] instance
        // [-1] instance context table ref
        assert(lua_type(L, -1) == LUA_TNUMBER);

        int context_table_ref = lua_tonumber(L, -1);

        lua_pop(L, 1);
        // [-1] instance

        uint32_t unique_script_id = INVALID_SCRIPT_ID;
        if (!GetMetaFunction(L, -1, META_GET_UNIQUE_SCRIPT_ID, sizeof(META_GET_UNIQUE_SCRIPT_ID) - 1))
        {
            dmLogError("CreateCallback failed: missing %s meta function for instance context table", "UNIQUE_SCRIPT");
            lua_pop(L, 1);
            return 0x0;
        }
        // [-2] instance
        // [-1] META_GET_UNIQUE_SCRIPT_ID()
        lua_pushvalue(L, -2); // push instance
        // [-3] instance
        // [-2] META_GET_UNIQUE_SCRIPT_ID()
        // [-1] instance
        lua_call(L, 1, 1);    // call __get_unique_script_id(self)
        // [-2] instance
        // [-1] unique script id
        unique_script_id = (uint32_t)lua_tointeger(L, -1);
        lua_pop(L, 1);
        // [-1] instance

        lua_pop(L, 1);

        lua_pushvalue(L, callback_stack_index);
        // [-1] callback