CMusicMath.hpp

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#ifndef __CMusicMath__
#define __CMusicMath__

#include "CTimeSignature.hpp"
#include <Basics/CString.hpp>

//  ===========================================================================

using Exponent::Music::CTimeSignature;
using Exponent::Basics::CString;

//  ===========================================================================

namespace Exponent
{
    namespace Music
    {
        class CMusicMath
        {
        public:

//  ===========================================================================

            const static double CMUSIC_MATH_FREQUENCY[];                    
            const static double CMUSIC_MATH_TIME[];                         
            const static double CMUSIC_MATH_SONG_PHASE[];                   
            const static double CMUSIC_MATH_SONG_POSITION[];                
//  ===========================================================================

            enum ETempoDivision
            {
                // Straight
                e_sixtyFourBars = 0,        
                e_thirtyTwoBars,            
                e_sixteenBars,              
                e_eightBars,                
                e_fourBars,                 
                e_twoBars,                  
                e_oneBar,                   
                e_halfBar,                  
                e_quarterBar,               
                e_eigthBar,                 
                e_sixteenthBar,             
                e_thirtySecondBar,          
                e_sixtyFourthBar,           
                // Triplet
                e_sixtyFourBarsTriplet,     
                e_thirtyTwoBarsTriplet,     
                e_sixteenBarsTriplet,       
                e_eightBarsTriplet,         
                e_fourBarsTriplet,          
                e_twoBarsTriplet,           
                e_oneBarTriplet,            
                e_halfBarTriplet,           
                e_quarterBarTriplet,        
                e_eigthBarTriplet,          
                e_sixteenthBarTriplet,      
                e_thirtySecondBarTriplet,   
                e_sixtyFourthBarTriplet,    
                // Dotted
                e_sixtyFourBarsDotted,      
                e_thirtyTwoBarsDotted,      
                e_sixteenBarsDotted,        
                e_eightBarsDotted,          
                e_fourBarsDotted,           
                e_twoBarsDotted,            
                e_oneBarDotted,             
                e_halfBarDotted,            
                e_quarterBarDotted,         
                e_eigthBarDotted,           
                e_sixteenthBarDotted,       
                e_thirtySecondBarDotted,    
                e_sixtyFourthBarDotted,     
                e_numTempoDivisions         
            };

//  ===========================================================================

            static double getRateInMilliseconds(const double bpm, const ETempoDivision tempoDivision, const CTimeSignature &timeSignature);

            static double getRateInHertz(const double bpm, const ETempoDivision tempoDivision);

            static ETempoDivision getClosestTempoDivisionToRateInHertz(const double bpm, const double frequency);

            static double getPhase(const ETempoDivision tempoDivision);

            static double getSongPhasePosition(const ETempoDivision tempoDivision);

//  ===========================================================================

            static double getNumberOfSamples(const double sampleRate, const double lengthInSeconds);

//  ===========================================================================

            static long getClosestMidiNote(const double frequency);

            static double getNoteFrequency(const long note);

            static double getNoteFrequency(const long note, const long octaveDetune, const long semiDetune, const long fineDetune);

//  ===========================================================================

            static double getTempoNoteShift(const double originalBpm, const double newBpm);

            static double getTimeStretch(const double originalBpm, const double newBpm);

            static double getNewTempoPitchShift(const double shift, const double bpm);

            static double getBpmFromTime(const double length, const CTimeSignature &timeSignature, const long numberOfBeats = 4);

            static double getTimeFromBpm(const double bpm, const CTimeSignature &timeSignature, const long numberOfBeats = 4);

//  ===========================================================================

            static void getADivisionString(CString &theString, const ETempoDivision tempoDivision);

//  ===========================================================================

        private:

//  ===========================================================================

            enum ETempoDivisionType
            {
                e_straight = 0,             
                e_triplet,                  
                e_dotted,                   
            };

//  ===========================================================================

            class CFrequencyTable
            {
            public:

                CFrequencyTable()
                {
                    // 12th root of 2
                    const double kappa = 1.059463094359;

                    // a
                    double frequency = 6.875;

                    // b
                    frequency *= kappa;

                    // bb
                    frequency *= kappa;

                    // c, frequency of midi note 0
                    frequency *= kappa;

                    // Generate 128 midi notes
                    for (long i = 0; i < 128; i++)
                    {
                        m_frequencyTable[i] = frequency;
                        frequency *= kappa;
                    }
                }

                CFrequencyTable &operator = (const CFrequencyTable &table)
                {
                    // copy 128 midi notes
                    for (long i = 0; i < 128; i++)
                    {
                        m_frequencyTable[i] = table.m_frequencyTable[i];
                    }
                    return *this;
                }

                double getFrequency(const long index) const
                {
                    if (index >= 0 && index < 128)
                    {
                        return m_frequencyTable[index];
                    }
                    return 0.0;
                }

//  ===========================================================================

            protected:

//  ===========================================================================

                double m_frequencyTable[128];                               
            };

//  ===========================================================================

            static ETempoDivision getAdjustedTempoDivision(const ETempoDivision division, ETempoDivisionType &type);

            static double convertValueToTempoDivisionType(const double value, const ETempoDivisionType type);

//  ===========================================================================

            const static CFrequencyTable CMUSIC_MATH_FREQUENCY_TABLE;       
            const static double CMUSIC_MATH_TRIPLET_TIME;                   
            const static double CMUSIC_MATH_DOTTED_TIME;                    
        };
    }
}
#endif  // End of CMusicMath.hpp

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