How would I go about implementing a stopwatch with different speeds?

Question

Ideally I would like to have something similar to the Stopwatch class but with an extra property called Speed which would determine how quickly the timer changes minutes. I am not quite sure how I would go about implementing this.

Edit

Since people don't quite seem to understand why I want to do this. Consider playing a soccer game, or any sport game. The halfs are measured in minutes, but the time-frame in which the game is played is significantly lower i.e. a 45 minute half is played in about 2.5 minutes.

Answer 1

I'm not entirely sure what you're looking to do (doesn't a minute always have 60 seconds?), but I'd utilize Thread.Sleep() to accomplish what you want.

Answer 2

Subclass it, call through to the superclass methods to do their usual work, but multiply all the return values by Speed as appropriate.

Answer 3

I would use the Stopwatch as it is, then just multiply the result, for example:

var Speed = 1.2; //Time progresses 20% faster in this example
var s = new Stopwatch();
s.Start();
  //do things
s.Stop();
var parallelUniverseMilliseconds = s.ElapsedMilliseconds * Speed;

Answer 4

According to modern physics, what you need to do to make your timer go "faster" is to speed up the computer that your software is running one. I don't mean the speed at wich it performs calculations, but the physical speed. The close you get to the speed of light ( the constant C ) the greater the rate at which time passes for your computer, so as you approach the speed of light, time will "speed up" for you.

Answer 5

The reason your simple "multiplication" doesn't work is that it doesn't speeding up the passing of time - the factor applies to all time that has passed, as well as time that is passing.

So, if you set your speed factor to 3 and then wait 10 minutes, your clock will correctly read 30 minutes. But if you then change the factor to 2, your clock will immediately read 20 minutes because the multiplication is applied to time already passed. That's obviously not correct.

I don't think the stopwatch is the class you want to measure "system time" with. I think you want to measure it yoruself, and store elapsed time in your own variable.

Assuming that your target project really is a game, you will likely have your "game loop" somewhere in code. Each time through the loop, you can use a regular stopwatch object to measure how much real-time has elapsed. Multiply that value by your speed-up factor and add it to a separate game-time counter. That way, if you reduce your speed factor, you only reduce the factor applied to passing time, not to the time you've already recorded.

You can wrap all this behaviour into your own stopwatch class if needs be. If you do that, then I'd suggest that you calculate/accumulate the elapsed time both "every time it's requested" and also "every time the factor is changed." So you have a class something like this (note that I've skipped field declarations and some simple private methods for brevity - this is just a rough idea):

public class SpeedyStopwatch 
{
    // This is the time that your game/system will run from
    public TimeSpan ElapsedTime
    {
       get 
       { 
           CalculateElapsedTime();
           return this._elapsedTime;
       }
    }

    // This can be set to any value to control the passage of time
    public double ElapsedTime
    {
       get  { return this._timeFactor; }
       set 
       { 
           CalculateElapsedTime();
           this._timeFactor = value;
       }
    }

    private void CalculateElapsedTime()
    {
       // Find out how long (real-time) since we last called the method
       TimeSpan lastTimeInterval = GetElapsedTimeSinceLastCalculation();

       // Multiply this time by our factor
       lastTimeInterval *= this._timeFactor;

       // Add the multiplied time to our elapsed time
       this._elapsedTime += lastTimeInterval;
    }
 }

Answer 6

It sounds like what you might actually be looking for is an event scheduler, where you specify that certain events must happen at specific points in simulated time and you want to be able to change the relationship between real time and simulated time (perhaps dynamically). You can run into boundary cases when you start to change the speed of time in the process of running your simulation and you may also have to deal with cases where real time takes longer to return than normal (your thread didn't get a time slice as soon as you wanted, so you might not actually be able to achieve the simulated time you're targeting.)

For instance, suppose you wanted to update your simulation at least once per 50ms of simulated time. You can implement the simulation scheduler as a queue where you push events and use a scaled output from a normal Stopwatch class to drive the scheduler. The process looks something like this:

Push (simulate at t=0) event to event queue
Start stopwatch
lastTime = 0
simTime = 0
While running
  simTime += scale*(stopwatch.Time - lastTime)
  lastTime = stopwatch.Time
  While events in queue that have past their time
      pop and execute event
      push (simulate at t=lastEventT + dt) event to event queue

This can be generalized to different types of events occurring at different intervals. You still need to deal with the boundary case where the event queue is ballooning because the simulation can't keep up with real time.