Messages

1

General / Re: SFML Game Book - Delta Time Question?

« on: February 02, 2014, 03:34:39 pm »

ah, thanks. I do suppose that saves time in the long run.

2

General / SFML Game Book - Delta Time Question?

« on: February 02, 2014, 03:17:34 pm »

Hi there, I've got a problem understanding the reason for passing the TimePerFrame variable to the update member function of the game class in the following code from chapter 1 of the book:

void Game::run()
{
        sf::Clock clock;
        sf::Time timeSinceLastUpdate = sf::Time::Zero;
        while (mWindow.isOpen())
        {
                sf::Time elapsedTime = clock.restart();
                timeSinceLastUpdate += elapsedTime;
                while (timeSinceLastUpdate > TimePerFrame)  // I understand the fixed time step loop
                {
                        timeSinceLastUpdate -= TimePerFrame;

                        processEvents();
                        update(TimePerFrame); //Mistake?? or Really Needed??
                }

                updateStatistics(elapsedTime);
                render();
        }
}
 

Could someone tell me why this is necessary?? It's defined as a constant never changing value. (.01666.....) Why not just define Game::PlayerSpeed to 1.66666 instead of passing the TimePerFrame value and then multiplying Game::PlayerSpeed by TimePerFrame. Some insight would be greatly appreciated.

Edit:
Sorry forgot Link to full source i'm trying:
https://github.com/SFML/SFML-Game-Development-Book/tree/master/01_Intro/Source