Lua Problem to get a Lua Table in LuaScript C++ Function.

[darkshin]

Hello Guys!!

I am having a trouble trying to get a Lua table at a C++ Function, in luascript.cpp.
Here is the code:

Lua file

function onUse(player, item, fromPosition, target, toPosition, isHotkey)

    local recipe = Recipe()

    local items = {
    item1 = {2157},
    valor1 = {50},
    item2 = {0},
    valor2 = {0},
    item3 = {0},
    valor3 = {0},
    item4 = {0},
    valor4 = {0},
    item5 = {0},
    valor5 = {0}
    }
   
    recipe:setRecipeItem(items)

end

C++ Function

int LuaScriptInterface::luaRecipeSetRecipeItem(lua_State* L)
{
    RecipeHandler* recipe = getUserdata<RecipeHandler>(L, 1);
    uint32_t items[5][2] = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } };

    lua_getglobal(L, "items");

    for (uint8_t i = 1; i < 5; ++i) {

        if (getField<uint32_t>(L, 2, "item" + std::to_string(i)) == 0 || getField<uint32_t>(L, 2, "valor" + std::to_string(i)) == 0) {
            std::cout << "[Error - LuaScriptInterface::SetRecipeItem] Null filed at: " << std::to_string(i) << std::endl;
            break;
        }
        else {
            items[i][1] = getField<uint32_t>(L, 2, "item" + std::to_string(i));
            items[i][2] = getField<uint32_t>(L, 2, "valor" + std::to_string(i));
        }
    }

    if (!isTable(L, 2)) {
        pushBoolean(L, false);
        return 1;
    }
    else {
   
        if (recipe) {
            std::cout << "[LuaScriptInterface::SetRecipeItem] Sending Values: " << std::to_string(items[1][1]) << std::endl;
            recipe->setRecipeItem(items);
        }
        else {
            lua_pushnil(L);
        }

    }

    return 1;
}

I am getting 0 at every"getField", so I assume that I am doing it wrong. Can anyone help me make it workout?

 

[Printer]

Wot?

 

[darkshin]

Wot?

Wot wot? haha

I am doing something wrong trying to receive a lua table to a function at server sources. Got it ?

 

[Non Sequitur]

Try this:

int LuaScriptInterface::luaRecipeSetRecipeItem(lua_State* L)
{
    RecipeHandler* recipe = getUserdata<RecipeHandler>(L, 1);
    if (!recipe) {
        lua_pushnil(L);
        return 1;
    }

    std::map<uint16_t, uint16_t> items;

    //push first key for next()
    lua_pushnil(L);
    while (lua_next(L, 2) != 0) {
        //right now -2 is key, -1 is value
        lua_rawgeti(L, -1, 1); //push itemid onto the stack
        lua_rawgeti(L, -2, 2); //push price onto the stack       
        uint16_t itemid = static_cast<uint16_t>(lua_tonumber(L, -2));
        uint16_t price = static_cast<uint16_t>(lua_tonumber(L, -1));
        items[itemid] = price;
        lua_pop(L, 3); // pop value, itemid and price, but leave the last key for next()
    }   

    recipe->setRecipeItem(items);
    // P.S: modify your function to receive a std::map<uint16_t, uint16_t> and then you can iterate over the items like this:
    /*
        for (const auto& it: items) {
            // it.first is the itemid
            // it.second is the price
        }
    */    
    return 0;
}

I have left some comments so you can grasp what is going on. You can then call your function like this:

function onUse(player, item, fromPosition, target, toPosition, isHotkey)

    local recipe = Recipe()

   
    local items = {
        {2157, 50},
        {2158, 100},
        {1988, 20}
    }
  
    recipe:setRecipeItem(items)
end

I hope it helps.

 

[darkshin]

Try this:

int LuaScriptInterface::luaRecipeSetRecipeItem(lua_State* L)
{
    RecipeHandler* recipe = getUserdata<RecipeHandler>(L, 1);
    if (!recipe) {
        lua_pushnil(L);
        return 1;
    }

    std::map<uint16_t, uint16_t> items;

    //push first key for next()
    lua_pushnil(L);
    while (lua_next(L, 2) != 0) {
        //right now -2 is key, -1 is value
        lua_rawgeti(L, -1, 1); //push itemid onto the stack
        lua_rawgeti(L, -2, 2); //push price onto the stack     
        uint16_t itemid = static_cast<uint16_t>(lua_tonumber(L, -2));
        uint16_t price = static_cast<uint16_t>(lua_tonumber(L, -1));
        items[itemid] = price;
        lua_pop(L, 3); // pop value, itemid and price, but leave the last key for next()
    } 

    recipe->setRecipeItem(items);
    // P.S: modify your function to receive a std::map<uint16_t, uint16_t> and then you can iterate over the items like this:
    /*
        for (const auto& it: items) {
            // it.first is the itemid
            // it.second is the price
        }
    */  
    return 0;
}

I hope it helps.

Hey @Non Sequitur ! It helped me alot with that function. However, I tried to use that code for a new function, but something is going wrong. Could you help me at this last one?

lua file:

local classItems = {
[2376] = {2144, 10}      
}

function onUse(player, item, fromPosition, target, toPosition, isHotkey)
    
    local recipe = Recipe()
    local tile = Tile(toPosition)
    local position = target:getPosition()

if tile then
           local items = tile:getItems()
           local finalItem = nil
           local itemArray = {}
           
           for key,valor in ipairs(items) do
              local id = valor:getId() 
             if classItems[id] then
                finalItem = id
                itemArray = classItems[id]
             end
           end
           
           if finalItem then

           for key,valor in ipairs(itemArray) do
           print(key, valor)
           end

           recipe:setRecipeClassItems(itemArray, finalItem, player, position)
           end
end
end

c++ function

RecipeHandler* recipe = getUserdata<RecipeHandler>(L, 1);

    if (!recipe) {
        lua_pushnil(L);
        return 1;
    }

    std::map<uint16_t, uint16_t> items;

    //push first key for next()
    lua_pushnil(L);
    while (lua_next(L, 2) != 0) {
        //right now -2 is key, -1 is value
        lua_rawgeti(L, -1, 1);
        lua_rawgeti(L, -2, 2); // ERROR AT THIS LINE..  ACCESS VIOLATING READING LOCATION 0x0...18
        uint16_t itemid = static_cast<uint16_t>(lua_tonumber(L, -2));
        uint16_t amount = static_cast<uint16_t>(lua_tonumber(L, -1));
        items[itemid] = amount;
        lua_pop(L, 3); // pop value, itemid and price, but leave the last key for next()
    }

    uint16_t itemID = getNumber<uint16_t>(L, 3);
    Position position = getPosition(L, 4);
    Player* player = getPlayer(L, 5);

    if (player) {
        recipe->setRecipeClasses(itemID, position, player, items);
    }

    return 1;

Does the error at the c++ functions means that the field is empty/nil ?

 

[Non Sequitur]

You're passing this table to the function:

{2144, 10}

When it expects a table of tables, like this:

{
    {2144, 10}
}

You should take a better look at the example in my last post.

 

[darkshin]

You're passing this table to the function:

{2144, 10}

When it expects a table of tables, like this:

{
    {2144, 10}
}

You should take a better look at the example in my last post.

Thank you! That's why it was returning null at the the second statement XD