_ak_value_ramp_8h

Wwise SDK 2024.1.0

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 // AkValueRamp.h
  
 /// \file 
 /// Linear interpolation services for plug-in parameters.
  
 #ifndef _AK_VALUERAMP_H_
 #define _AK_VALUERAMP_H_
  
 #include <AK/SoundEngine/Common/AkTypes.h>
 #include <AK/Tools/Common/AkAssert.h>
 #include <math.h>
  
 namespace AK
 {
  
     /// Platform-independent parameter interpolation service for software plug-ins.
     /// \aknote
     /// Algorithm performs linear interpolation.
     /// \endaknote
     /// \sa
     /// - \ref shared_parameter_interface
     class CAkValueRamp
     {
     public:
  
         /// Constructor method.
         CAkValueRamp() :
         m_fStepIncrement( 0.f ),    // Step increment sign
             m_fInc( 0.f ),          // Signed increment
             m_fTarget( 0.f ),       // Target gain for ramping
             m_fCurrent( 0.f ),      // Current interpolated value
             m_uRampCount( 0 ),      // Position in interpolation ramp
             m_uRampLength( 0 )      // Total duration of interpolation ramp
         {
         }
  
         /// Destructor method.
         ~CAkValueRamp()
         {
         }
  
         /// Initial parameter interpolation ramp setup.
         inline void RampSetup( 
             AkReal32 fStepIncrement,    ///< Increment to add to the parameter at every Tick() call
             AkReal32 fInitVal           ///< Initial ramp value
             )
         {
             AKASSERT( fStepIncrement > 0.f );
             m_fStepIncrement = fStepIncrement;
             m_fCurrent = fInitVal;
             SetTarget( fInitVal );
         }
  
         /// Set the ramp's target value.
         AkForceInline void SetTarget( 
             AkReal32 fTarget        ///< Target ramp value
             ) 
         {
             m_fTarget = fTarget;
             m_uRampCount = 0;
             AkReal32 fDiff = m_fTarget - m_fCurrent;
             m_uRampLength = static_cast<AkUInt32>( fabs(fDiff) / m_fStepIncrement );
             m_fInc = fDiff > 0 ? m_fStepIncrement : -m_fStepIncrement;
         }
  
         /// Process a single interpolation frame.
         /// \return The current interpolated value
         AkForceInline AkReal32 Tick()
         {
             if ( m_uRampCount >= m_uRampLength )
                 m_fCurrent = m_fTarget;
             else
             {
                 ++m_uRampCount;
                 m_fCurrent += m_fInc;
             }
             return m_fCurrent;
         }
         
         /// Retrieve the current interpolated value.
         /// \return The current interpolated value
         AkReal32 GetCurrent()                       { return m_fCurrent; }
         
         /// Set the current interpolated value.
         void SetCurrent(AkReal32 in_fCurrent)       { m_fCurrent = in_fCurrent; }
  
         /// Retrieve the current interpolation frame count.
         /// \return The current interpolation frame count
         AkUInt32 GetRampCount()                     { return m_uRampCount; }
  
         /// Set the current interpolation frame count.
         void SetRampCount(AkUInt32 in_uRampCount)   { m_uRampCount = in_uRampCount; }
  
         /// The ramp is no longer necessary; set to target
         void StopRamp()
         {
             m_fCurrent = m_fTarget;
             m_uRampCount = m_uRampLength;
         }
  
     private:
  
         AkReal32            m_fStepIncrement;       // Step increment size
         AkReal32            m_fInc;                 // Signed increment
         AkReal32            m_fTarget;              // Target for interpolation ramp
         AkReal32            m_fCurrent;             // Current interpolated value
         AkUInt32            m_uRampCount;           // Position in interpolation ramp
         AkUInt32            m_uRampLength;          // Total duration of interpolation ramp
     };
 }
  
 #endif  //_AK_VALUERAMP_H_