Operator '*' is ambiguous (C++)

Question

Recently I have been making a test "game" in C++ (to get used with SFML). I have made a Super Mario sprite as shown below

sf::Texture SuperMarioAnim;
if (!SuperMarioAnim.loadFromFile("img/image.png"))
{
    std::wcout << L"Συγγνώμη, η εικόνα SuperMarioAnim δεν υπάρχει ή διαγράφηκε";
}

sf::Sprite SuperMario;
SuperMario.setTexture(SuperMarioAnim);
SuperMario.setPosition(200, 2900);

I also made a player_speed integer, with the value of the speed of the player, obviously, and I also created a time object equal to the value we get from clock.getElapsedTime() :

int player_spd = 30;

while (window.isOpen())
{
    //...
    sf::Time time;
    time = clock.getElapsedTime();
    //...
}

However, when I tell the sprite to move in the X axis with this:

if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
    SuperMario.move(sf::Vector2f((player_spd * time), 0));

I get this error: 1>c:\\[directory]\\visual studio 2017\\projects\\test_game\\test_game\\test_game.cpp(180): error C2593: 'operator *' is ambiguous (line 180 is the SuperMario.move command right above)

Could someone specify what I did wrong? I am using Visual Studio 2017 and SFML 2.4

Answer 1

sf::Time defines these overloads of operator* ¹ :

Time    operator* (Time left, float right)
    //Overload of binary * operator to scale a time value. 

Time    operator* (Time left, Int64 right)
    //Overload of binary * operator to scale a time value. 

Time    operator* (float left, Time right)
    //Overload of binary * operator to scale a time value. 

Time    operator* (Int64 left, Time right)
    //Overload of binary * operator to scale a time value. 

The error indicates that overload resolution failed because it can't choose among them. player_spd is an int . And calling operator* will require converting it to either float or Int64 . Neither is better than the other (according to the error message). So it's ambiguous.

You can cast, or just define player_spd as one of the types that sf::Time can be multiplied by.

Answer 2

'clock.getElapsedTime()' returns a 'Time' object. You have the option of returning a float from a 'Time' object as 'asSeconds()', 'asMilliseconds()', or 'asMicroseconds()'. I believe this will solve your error, but am unable to test on my end. I would also recommend changing 'player_spd' to a float.

if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
    SuperMario.move(player_spd * time.asSeconds()), 0));

Good luck!