using UnityEngine;
using System.Collections;
 
[AddComponentMenu( "Utilities/HUDFPS")]
public class FPSCounter : MonoBehaviour
{
 //fps 顯示的初始位置和大小
 public Rect startRect=new Rect(512, 10f, 75f, 50f );
 //fps 過低時是否改變UI顏色
 public bool updateColor = true;
 //fps UI 是否允許拖動 
 public bool allowDrag = true; 
 //fps 更新的頻率
 public float frequency = 0.5F;
 //fps 顯示的精度
 public int nbDecimal = 1; 
 //一定時間內的fps數量
 private float accum = 0f;
 //fps計算的時間
 private int frames = 0;
 //GUI 依賴fps的顏色 fps<10 紅色 fps<30 黃色 fps>=30 綠色
 private Color color = Color.white;
 //fps 
 private string sFPS = "";
 //GUI 的樣式
 private GUIStyle style;
 
 void Start()
 {
 StartCoroutine(FPS());
 }
 
 void Update()
 {
 accum += Time.timeScale/ Time.deltaTime;
 ++frames;
 }
 
 IEnumerator FPS()
 {
 while( true )
 {
 //更新fps
 float fps = accum/frames;
 sFPS = fps.ToString( "f" + Mathf.Clamp( nbDecimal, 0, 10 ) );
 
 //更新顏色
 color = (fps >= 30) ? Color.green : ((fps > 10) ? Color.yellow : Color.red);
 
 accum = 0.0F;
 frames = 0;
 
 yield return new WaitForSeconds( frequency );
 }
 }
 
 void OnGUI()
 {
 if( style == null ){
 style = new GUIStyle( GUI.skin.label );
 style.normal.textColor = Color.white;
 style.alignment = TextAnchor.MiddleCenter;
 }
 
 GUI.color = updateColor ? color : Color.white;
 startRect = GUI.Window(0, startRect, DoMyWindow, "");
 }
 
 void DoMyWindow(int windowID)
 {
 GUI.Label( new Rect(0, 0, startRect.width, startRect.height), sFPS + " FPS", style );
 if( allowDrag ) GUI.DragWindow(new Rect(0, 0, Screen.width, Screen.height));
 }
}