Pausing an XNA game

Question

So I'm following a tutorial:

http://msdn.microsoft.com/en-us/library/bb195026%28v=xnagamestudio.31%29.aspx#Y539

to create a way to pause the game I'm making. But I'm stuck because the code includes "Simulate" which is not explained in the tutorial. I understand what it supposed to do.

It brings up an error about it doesn't exist - so my guess it that it needs to be created like a variable?

Heres the code:

if (!paused)
{
    Simulate(gameTime);
}

Could someone point me in the correct direction please? Thanks :)

Answer 1

It's just a simple way to wrap your entire Update method in a conditional, without mixing the pausing logic with your game's updating logic.

So instead of:

protected override void Update(GameTime gameTime)
{
    if(!paused)
    {
        // Lots and lots of code!
    }
}

You can have:

private void Simulate(GameTime gameTime)
{
    // Lots and lots of code!
}

protected override void Update(GameTime gameTime)
{
    if(!paused)
    {
        Simulate(gameTime);
    }
}

Of course, if you would prefer to express it as "continue the game like normal", you could also do this:

protected override void Update(GameTime gameTime)
{
    if(paused)
        return;

    // Lots and lots of code!
}

These all do the same thing. Which method you choose to do it is simply a matter of taste. Basically what the tutorial is telling you is:

• Determine if your game should be paused and store that in a variable (ie: bool paused)
• If it is paused, skip over the code that is responsible for updating your game's state (essentially freezing it in time, ie: "pausing" it.)

Answer 2

As Andrew mentioned, you can simply add a flag in the Update loop to check the game's state. However, if your game is a bit more complex, you might want to take a look at the Game State Management code sample, that demonstrates multiple screens, transitions and a pause menu.