00001 
00002 //
00003 // Copyright (c) 2006 Audiokinetic Inc. / All Rights Reserved
00004 //
00006  
00007 #ifndef _AKFXDURATIONHANDLER_H_
00008 #define _AKFXDURATIONHANDLER_H_
00009 
00010 #include <AK/SoundEngine/Common/AkTypes.h>
00011 
00014 class AkFXDurationHandler
00015 {
00016 public:
00017 
00019     inline void Setup(  
00020         AkReal32 in_fDuration,      
00021         AkInt16 in_iLoopingCount,   
00022         AkUInt32 in_uSampleRate     
00023         )
00024     {
00025         m_uSampleRate = in_uSampleRate;
00026         SetDuration( in_fDuration );
00027         SetLooping( in_iLoopingCount );
00028         Reset();
00029     }
00030 
00032     inline void Reset()
00033     {
00034         m_uFrameCount = 0;
00035     }
00036 
00038     inline void SetLooping( AkInt16 in_iNumLoops )
00039     {
00040         m_iNumLoops = in_iNumLoops;
00041     }
00042 
00044     inline void SetDuration( AkReal32 in_fDuration )
00045     {
00046         m_uIterationFrame = (AkUInt32) (in_fDuration*m_uSampleRate);
00047         m_uIterationFrame = (m_uIterationFrame + 3) & ~3; // Align to next 4 frame boundary for SIMD alignment
00048     }
00049 
00051     inline AkReal32 GetDuration() const
00052     {
00053         // Note: Infinite looping will return a duration of 0 secs.
00054         return (AkReal32)(m_uIterationFrame*m_iNumLoops)/m_uSampleRate;
00055     }
00056 
00059     inline void ProduceBuffer( AkAudioBuffer * io_pBuffer )
00060     {
00061         io_pBuffer->eState = ProduceBuffer( io_pBuffer->MaxFrames(), io_pBuffer->uValidFrames );
00062     }
00063 
00066     inline AKRESULT ProduceBuffer( AkUInt16 in_uMaxFrames, AkUInt16 & out_uValidFrames )
00067     {
00068         // Infinite looping or not reached the end, always producing full capacity
00069         out_uValidFrames = in_uMaxFrames;
00070         AKRESULT eState = AK_DataReady;
00071 
00072         if ( m_iNumLoops != 0 )
00073         {
00074             // Finite looping, produce full buffer untill the end.
00075             const AkUInt32 uTotalFrames = m_iNumLoops*m_uIterationFrame;
00076             if ( m_uFrameCount < uTotalFrames )
00077             {
00078                 const AkUInt32 uFramesRemaining = uTotalFrames-m_uFrameCount;
00079                 if ( uFramesRemaining <= in_uMaxFrames )
00080                 {
00081                     out_uValidFrames = (AkUInt16)uFramesRemaining;
00082                     eState = AK_NoMoreData;
00083                 }
00084             }
00085             else
00086             {
00087                 out_uValidFrames = 0;
00088                 eState = AK_NoMoreData;
00089             }
00090         }   
00091         m_uFrameCount += out_uValidFrames;
00092 
00093         return eState;
00094     }
00095 
00096 protected:
00097 
00098     AkUInt32    m_uIterationFrame;  // Number of frames in a single loop iteration 
00099     AkUInt32    m_uFrameCount;      // Number of frames output in the current iteration
00100     AkUInt32    m_uSampleRate;      // Sample rate used to convert time to samples
00101     AkInt16     m_iNumLoops;        // Number of loop iterations (0 == infinite looping)
00102     
00103 };
00104 
00105 #endif // _AKFXDURATIONHANDLER_H_