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Clock.cpp
Package: OpenGL动画演示(包含代码).rar　[view]
Upload User: sz83729876
Upload Date: 2013-03-07
Package Size: 4140k
Code Size: 4k
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OpenGL program

Development Platform:

Windows_Unix

Clock.cpp：Code Content
  1. #include "Clock.h"
  3. //-------------------------------------------------------
  4. //  Static variables
  5. //-------------------------------------------------------
  6. LARGE_INTEGER   Timer::m_llPerformanceFreq;
  7. LARGE_INTEGER   Timer::m_llBeginTime;
  8. LARGE_INTEGER   Timer::m_llLastTime;
  9. LARGE_INTEGER   Timer::m_llCurTime;
  11. float           Timer::m_fTimeScale;
  13. float           Timer::m_fBeginTime;
  14. float           Timer::m_fCurrentTime;
  15. float           Timer::m_fSecSinceLastFrame;
  17. float           Timer::m_fCounter;
  18. float           Timer::m_fFPS, Timer::m_fTempFPS;
  19. long            Timer::m_dwFrameCount;
  21. //-------------------------------------------------------
  22. //  Initialize()
  23. //-------------------------------------------------------
  24. //      Checks performance counter for it's
  25. //      frequency (if it exists) and resets the 
  26. //      counters.
  27. //
  28. bool Timer::Initialize()
  29. {
  30.     if ( QueryPerformanceFrequency( &m_llPerformanceFreq ) )
  31.     {
  32.         QueryPerformanceCounter( &m_llBeginTime );
  33.         m_llLastTime.QuadPart = m_llBeginTime.QuadPart;
  34.         m_llCurTime.QuadPart = m_llBeginTime.QuadPart;
  35.         m_fTimeScale = 1.0f / m_llPerformanceFreq.QuadPart;
  37.         m_fBeginTime          = m_llBeginTime.QuadPart * m_fTimeScale;
  38.         m_fCurrentTime        = m_llBeginTime.QuadPart * m_fTimeScale;
  39.         m_fSecSinceLastFrame  = 0.0f;
  40.         m_fCounter            = 0.0f;
  41.         m_fFPS                = 0.0f;
  42.         m_fTempFPS            = 0.0f;
  43.         m_dwFrameCount        = 0;
  45.         return true;
  46.     }
  48.     return false;
  49. }
  51. //-------------------------------------------------------
  52. //  GetTimer()
  53. //-------------------------------------------------------
  54. //      Retrieves one of the four timer values.
  55. //
  56. //      TIMER_APPSTART
  57. //          Returns the time when the app started.
  58. //
  59. //      TIMER_SINCEAPPSTART
  60. //          Returns the time elapsed since the 
  61. //          app started. 
  62. //
  63. //      TIMER_SINCELASTFRAME
  64. //          Returns the time it took the to render
  65. //          the last frame.
  66. //
  67. //      TIMER_ACTUAL
  68. //          Returns the *actual* time at the moment
  69. //          GetTimer() is called.
  70. //
  71. float Timer::GetTimer( TIMER_TYPE enumType )
  72. {
  73.     LARGE_INTEGER ct;
  74.     switch( enumType )
  75.     {
  76.         case TIMER_APPSTART:
  77.             return m_fBeginTime;
  78.         case TIMER_SINCEAPPSTART:
  79.             return m_fCurrentTime;
  80.         case TIMER_SINCELASTFRAME:
  81.             return m_fSecSinceLastFrame;
  82.         case TIMER_ACTUAL:
  83.             QueryPerformanceCounter( &ct );
  84.             return ( (ct.QuadPart-m_llBeginTime.QuadPart) * m_fTimeScale );
  85.     }
  86.     return -1.0f;
  87. }
  89. //-------------------------------------------------------
  90. //  OncePerFrameQuery()
  91. //-------------------------------------------------------
  92. //      Called once per frame to get the current
  93. //      time and calculate the fps and other things
  94. //      from that.
  95. //
  96. bool Timer::OncePerFrameQuery( HWND hWnd )
  97. {
  98.     m_llLastTime = m_llCurTime;
  100.     if (!QueryPerformanceCounter( &m_llCurTime ))
  101.         return false;
  103.     m_fCurrentTime       = (float)( (m_llCurTime.QuadPart-m_llBeginTime.QuadPart) * m_fTimeScale );
  104.     m_fSecSinceLastFrame = (float)( (m_llCurTime.QuadPart-m_llLastTime.QuadPart) * m_fTimeScale );
  105.     m_fFPS = 1.0f / m_fSecSinceLastFrame;
  107.     m_dwFrameCount++;
  109.     m_fCounter += m_fSecSinceLastFrame;
  110.     if ( m_fCounter>= 1.0f )
  111.     {
  112.         char ss[128];
  113.         sprintf( ss, "The Hollow   %1.2f fps   running %1.2f seconds", m_fFPS, m_fCurrentTime );
  114.         SetWindowText( hWnd, ss );
  115.         m_fCounter = 0.0f;
  116.     }
  118.     return true;
  119. }
  121. //-------------------------------------------------------
  122. //  OncePerFrameQuery()
  123. //-------------------------------------------------------
  124. //      Returns the current frames per second.
  125. //
  126. float Timer::GetFPS()
  127. {
  128.     return m_fFPS;
  129. }