Scaling a value based on FPS?

Game Mechanics
#1

Hi

I was just wondering if there was a way to scale values based on FPS, if the entities move at fixed time intervals rather than based on frame count. For example, if player A gets 120 fps and player B gets 170 fps is there a way to scale the players speed so that both players would have an equal advantage?

CopyableCougar4

#2

You would use delta time.
Basically the time that has passed since the last update.

Then instead of moving objects a set amount per frame you would move them based on milliseconds.

example:


public void update(int deltaTime)
{
    this.x += dx * deltaTime;
}

Edit:
It’s a very commonly used method for gameloops, so it should be easy to find examples on google :slight_smile:

#3

Hi

That is probably going to be my best option :slight_smile: Thanks :slight_smile:

CopyableCougar4

#4

A word of caution with this method though:
If you for some reason have a huge lag spike or if you minimize the game (LWJGL) then your game will try to catch up and update with a deltaTime of thousands of milliseconds!
Not a huge problem but remember it :slight_smile:

#5

Hi

Thanks for the word of caution, but as of now the window is fullscreen and hitting escape will destroy the display :slight_smile: Also, as of now I took your idea and added it with only about 7-8 lines of code and it works beautifully :slight_smile: (It was noticeable before because two different sections of the world caused different FPS counts and the speed boost used to be noticeable).

CopyableCougar4

#6

I have a nice little explanation on delta time here (not very technical but it’s only meant to help you understand what delta time is), if you’re interested check it out. :slight_smile: