How do you separate game logic from display?

Question

How can you make the display frames per second be independent from the game logic? That is so the game logic runs the same speed no matter how fast the video card can render

Answer 1

You could make your game loop look like:

int lastTime = GetCurrentTime();
while(1) {
    // how long is it since we last updated?
    int currentTime = GetCurrentTime();
    int dt = currentTime - lastTime;
    lastTime = currentTime;

    // now do the game logic
    Update(dt);

    // and you can render
    Draw();
}

Then you just have to write your Update() function to take into account the time differential; e.g., if you've got an object moving at some speed v, then update its position by v * dt every frame.