Question

I have a simple timer class in a game, intended to allow me to make an entity do something every so many seconds. It has two functions:

void Timer::GameTimer() // Gets time between frames
{
    ::ElapsedTime = Clock.GetElapsedTime();
    Clock.Reset();
}

This just updates the ElapsedTime Global so that it can be grabbed by anything that needs it. It’s placed inside the gameloop.

Then the important one:

bool Timer::tCounter(int total) // Returns true every 'total' seconds
{
    static float ftime; // Variable to hold the mounting elapsed time
    static int n; // Counter variable for true trigger

    ftime += ElapsedTime;

    int itime = (int)ftime; //Truncate

    if(!(itime%total) && itime != 0)
    {
        n++;
    }
    else
    {
        n = 0;
    }

    if (n == 1)
    {
        return true;
    }
    else
    {
        return false;
    }
}

Timer is instantiated inside the Entity class as Timer::Timer timer

The function is then called inside Entity::Update once per loop for every instance of the entity class in the game:

if (timer.tCounter(2))
    {
        Do stuff
    }

The problem is it doesn’t seem to count uniquely for each instance of Entity, resulting in only one doing stuff at a time and other weird stuff occasionally happening. The problem seems to be the static variables being shared. How do I ensure that this tCounter function holds unique variables for each instance that calls it?

Answer 1

static in this context means only one instance of something exists at a time and is initialized once.

The easiest fix to me would be to (not necessarily the best fix):
– Remove the static qualifier
– make ftime and n member variables of Timer
– Create an instance of Timer for each entity that you want to react to a timer.