Adding a frames-per-second counter

The frames per second (FPS) counter is the cornerstone of all graphical application profiling and performance measurements. In this recipe, we will learn how to implement a simple FPS counter class and use it to roughly measure the performance of a running application.

Getting ready

The source code for this recipe can be found in Chapter4/GL02_FPS.

How to do it...

Let's implement the FramesPerSecondCounter class containing all the machinery required to calculate the average FPS rate for a given time interval:

1. First, we need some member fields to store the duration of a sliding window, the number of frames rendered in the current interval, and the accumulated time of this interval:

   class FramesPerSecondCounter {
   private:
     const float avgIntervalSec_ = 0.5f;
     unsigned int numFrames_ = 0;
     double accumulatedTime_ = 0;
     float currentFPS_ = 0.0f;

2. The single constructor can override...