Countdown Timer for Racing Game

Question

I want to make a countdown timer for my racing game such as "3... 2... 1... GO!" I'm using GLUT, OpenGL, and C++. I was wondering what the most appropriate method to handle this in C++. clock()? glutTimerFunc()? I plan on having 4 textured polygons that shrink and fade one after the other.

Answer 1

You need to accumulate time in your update loop. Don't think in terms of "what time it is", instead, keep a double variable, called timeTotal. Each frame, increment it by (1.0/60.0) (or whatever your fixed timestep is). When the game starts, you can reset the timer, and your race start introduction would just go something like this:

void update()
{
  totalTime += 1.0/60.0 ; //increase time

  if( timeTotal > 1 )  // 3.
  else if( timeTotal > 2 )  // 2.
  else if( timeTotal > 3 )  // 1
  else { GO } // race on

}

You can refactor this in any number of ways, but this is the basic idea of how to trip time based events in a game system.