Question

I’m ripping my hair out over this one. For some odd reason I cannot find out / think of how to move a sprite in SFML and or SDL. The tutorials I’ve looked at for both libraries state nothing about this; so I assume that it’s more of a C++ thing than a library thing.

So I was wondering; how do you move a sprite?

(When I say move, I mean have the sprite “glide” across the window at a set speed)

Answer 1

You need a loop that gets called a fixed number of times per second, then you update the x,y values of the sprite each frame.

For SFML you have sprite.move

while (App.IsOpened())
{
    // Process events
    sf::Event Event;
    while (App.GetEvent(Event))
    {
        if (Event.Type == sf::Event::Closed)
            App.Close();
    }

    // Get elapsed time
    float ElapsedTime = App.GetFrameTime();

    // Move the sprite
    if (App.GetInput().IsKeyDown(sf::Key::Left))  Sprite.Move(-100 * ElapsedTime, 0);
    if (App.GetInput().IsKeyDown(sf::Key::Right)) Sprite.Move( 100 * ElapsedTime, 0);
    if (App.GetInput().IsKeyDown(sf::Key::Up))    Sprite.Move(0, -100 * ElapsedTime);
    if (App.GetInput().IsKeyDown(sf::Key::Down))  Sprite.Move(0,  100 * ElapsedTime);
}