AudioEngine: make humanization parameters member

Previously the standard deviations used to create random Gaussian distributed number for the humanization of velocity, pitch, and timing were just magic numbers. Well, there are actual values are still quite magic but at least there are now reusable static members and documented.

src/core/AudioEngine/AudioEngine.cpp

@@ -1158,13 +1158,13 @@ void AudioEngine::processPlayNotes( unsigned long nframes )
 			if ( pSong->getHumanizeVelocityValue() != 0 ) {
 				pNote->set_velocity( pNote->get_velocity() +
 									 pSong->getHumanizeVelocityValue() *
-									 getGaussian( 0.2 ) );
+									 getGaussian( AudioEngine::fHumanizeVelocitySD ) );
 			}
 
 			float fPitch = pNote->get_pitch() + pNote->get_instrument()->get_pitch_offset();
-			const float fRandomPitchFactor = pNote->get_instrument()->get_random_pitch_factor();
-			if ( fRandomPitchFactor != 0. ) {
-				fPitch += getGaussian( 0.4 ) * fRandomPitchFactor;
+			if ( pNote->get_instrument()->get_random_pitch_factor() != 0. ) {
+				fPitch += getGaussian( AudioEngine::fHumanizePitchSD ) *
+					pNote->get_instrument()->get_random_pitch_factor();
 			}
 			pNote->set_pitch( fPitch );
 
@@ -2381,11 +2381,10 @@ int AudioEngine::updateNoteQueue( unsigned nIntervalLengthInFrames )
 						* random variable.
 						*/
 						if ( pSong->getHumanizeTimeValue() != 0 ) {
-							nOffset += ( int )(
-										getGaussian( 0.3 )
-										* pSong->getHumanizeTimeValue()
-										* AudioEngine::nMaxTimeHumanize
-										);
+							nOffset += (int) (
+								getGaussian( AudioEngine::fHumanizeTimingSD ) *
+								pSong->getHumanizeTimeValue() *
+								AudioEngine::nMaxTimeHumanize );
 						}
 
 						// Lead or Lag
@@ -2592,7 +2591,10 @@ QString AudioEngine::toQString( const QString& sPrefix, bool bShort ) const {
 			sOutput.append( nn->toQString( sPrefix + s, bShort ) );
 		}
 		sOutput.append( QString( "]\n%1%2m_pMetronomeInstrument: %3\n" ).arg( sPrefix ).arg( s ).arg( m_pMetronomeInstrument->toQString( sPrefix + s, bShort ) ) )
-			.append( QString( "%1%2nMaxTimeHumanize: %3\n" ).arg( sPrefix ).arg( s ).arg( AudioEngine::nMaxTimeHumanize ) );
+			.append( QString( "%1%2nMaxTimeHumanize: %3\n" ).arg( sPrefix ).arg( s ).arg( AudioEngine::nMaxTimeHumanize ) )
+			.append( QString( "%1%2fHumanizeVelocitySD: %3\n" ).arg( sPrefix ).arg( s ).arg( AudioEngine::fHumanizeVelocitySD ) )
+			.append( QString( "%1%2fHumanizePitchSD: %3\n" ).arg( sPrefix ).arg( s ).arg( AudioEngine::fHumanizePitchSD ) )
+			.append( QString( "%1%2fHumanizeTimingSD: %3\n" ).arg( sPrefix ).arg( s ).arg( AudioEngine::fHumanizeTimingSD ) );
 
 	}
 	else {
@@ -2647,7 +2649,10 @@ QString AudioEngine::toQString( const QString& sPrefix, bool bShort ) const {
 			sOutput.append( nn->toQString( sPrefix + s, bShort ) );
 		}
 		sOutput.append( QString( "], m_pMetronomeInstrument: id = %1" ).arg( m_pMetronomeInstrument->get_id() ) )
-			.append( QString( ", nMaxTimeHumanize: id %1" ).arg( AudioEngine::nMaxTimeHumanize ) );
+			.append( QString( ", nMaxTimeHumanize: id %1" ).arg( AudioEngine::nMaxTimeHumanize ) )
+			.append( QString( ", fHumanizeVelocitySD: id %1" ).arg( AudioEngine::fHumanizeVelocitySD ) )
+			.append( QString( ", fHumanizePitchSD: id %1" ).arg( AudioEngine::fHumanizePitchSD ) )
+			.append( QString( ", fHumanizeTimingSD: id %1" ).arg( AudioEngine::fHumanizeTimingSD ) );
 	}
 
 	return sOutput;

src/core/AudioEngine/AudioEngine.h

@@ -128,6 +128,36 @@ class AudioEngine : public H2Core::Object<AudioEngine>
 		Testing = 6
 	};
 
+	/**
+	 * Maximum value the standard deviation of the Gaussian
+	 * distribution the random velocity contribution will be drawn
+	 * from can take.
+	 *
+	 * The actual standard deviation used during processing is this
+	 * value multiplied with #Song::m_fHumanizeVelocityValue.
+	 */
+	static constexpr float fHumanizeVelocitySD = 0.2;
+	/**
+	 * Maximum value the standard deviation of the Gaussian
+	 * distribution the random pitch contribution will be drawn from
+	 * can take.
+	 *
+	 * The actual standard deviation used during processing is this
+	 * value multiplied with #Instrument::__random_pitch_factor of the
+	 * instrument associated with the particular #Note.
+	 */
+	static constexpr float fHumanizePitchSD = 0.4;
+	/**
+	 * Maximum value the standard deviation of the Gaussian
+	 * distribution the random pitch contribution will be drawn from
+	 * can take.
+	 *
+	 * The actual standard deviation used during processing is this
+	 * value multiplied with #Instrument::__random_pitch_factor of the
+	 * instrument associated with the particular #Note.
+	 */
+	static constexpr float fHumanizeTimingSD = 0.3;
+
 	AudioEngine();
 
 	~AudioEngine();

src/core/AudioEngine/AudioEngineTests.cpp

@@ -1430,24 +1430,18 @@ void AudioEngineTests::testHumanization() {
 		// multiplied with the humanization value set via the
 		// GUI. With the latter ranging from 0 to 1 the factor
 		// represent the maximum standard deviation available.
-		checkDeviation( &deviationsVelocity, 0.2 * fValue, "velocity" );
+		checkDeviation( &deviationsVelocity,
+						AudioEngine::fHumanizeVelocitySD * fValue, "velocity" );
 		checkDeviation( &deviationsTiming,
-						0.3 * AudioEngine::nMaxTimeHumanize * fValue, "timing" );
-		checkDeviation( &deviationsPitch, 0.4 * fValue, "pitch" );
+						AudioEngine::fHumanizeTimingSD *
+						AudioEngine::nMaxTimeHumanize * fValue, "timing" );
+		checkDeviation( &deviationsPitch,
+						AudioEngine::fHumanizePitchSD * fValue, "pitch" );
 	};
 
 	setHumanization( 0.2 );
 	std::vector<std::shared_ptr<Note>> notesHumanizedWeak;
 	getNotes( &notesHumanizedWeak );
-
-	// qDebug() << "reference";
-	// for ( auto note : notesReference ) {
-	// 	qDebug() << note->toQString();
-	// }
-	// qDebug() << "custom";
-	// for ( auto note : notesCustomized ) {
-	// 	qDebug() << note->toQString();
-	// }
 	checkHumanization( 0.2, &notesHumanizedWeak );
 
 	setHumanization( 0.8 );

src/core/Basics/Instrument.h

@@ -350,7 +350,13 @@ class Instrument : public H2Core::Object<Instrument>
 		bool					__filter_active;		///< is filter active?
 		float					__filter_cutoff;		///< filter cutoff (0..1)
 		float					__filter_resonance;		///< filter resonant frequency (0..1)
-		float					__random_pitch_factor;	///< random pitch factor
+	/**
+	 * Factor to scale the random contribution when humanizing pitch
+	 * between 0 and #AudioEngine::fHumanizePitchSD.
+	 *
+	 * Supported range [0,1].
+	 */
+		float					__random_pitch_factor;
 		float					__pitch_offset;	///< instrument main pitch offset
 		int						__midi_out_note;		///< midi out note
 		int						__midi_out_channel;		///< midi out channel

src/core/Basics/Song.h

@@ -350,7 +350,19 @@ class Song : public H2Core::Object<Song>, public std::enable_shared_from_this<So
 		 */
 		LoopMode		m_loopMode;
 		PatternMode		m_patternMode;
+		/**
+		 * Factor to scale the random contribution when humanizing
+		 * timing between 0 and #AudioEngine::fHumanizeTimingSD.
+		 *
+		 * Supported range [0,1].
+		 */
 		float			m_fHumanizeTimeValue;
+		/**
+		 * Factor to scale the random contribution when humanizing
+		 * velocity between 0 and #AudioEngine::fHumanizeVelocitySD.
+		 *
+		 * Supported range [0,1].
+		 */
 		float			m_fHumanizeVelocityValue;
 		float			m_fSwingFactor;
 		bool			m_bIsModified;