duck

// Frames Per Second visual display
// Robotduck 2010

using UnityEngine;
using System.Collections;

public class FramesPerSecond : MonoBehaviour {

    private float updatePeriod = 0.5f;
    private float[] runningAverages = { 60, 60, 60, 60, 60 };
    private int runningAverageIndex = 0;
    private float fps;
    private float countFrames = 0;
    private float nextAverageTime;
    private float lastSampleTime;

    void Start ()
    {
        float now = Time.realtimeSinceStartup;
        nextAverageTime = now + updatePeriod;
        lastSampleTime = now;
    }

    void Update ()
    {
        float now = Time.realtimeSinceStartup;
        if (now > nextAverageTime)
        {
            float samplePeriod = now - lastSampleTime;
            lastSampleTime = now;
            float periodFPS = countFrames / samplePeriod;
            runningAverageIndex++;
            runningAverageIndex %= runningAverages.Length;
            runningAverages[runningAverageIndex] = periodFPS;

            fps = 0;
            foreach(float entry in runningAverages)
            {
                fps += entry;
            }
            fps /= runningAverages.Length;

            nextAverageTime += updatePeriod;
            countFrames = 0;
        }

        countFrames++;
    }

    void OnGUI ()
    {
        GUI.Label (new Rect (10, 10, 100, 20), ((int) fps)+" FPS");
    }
}