BALibrary_parasitstudio/src/AudioEffectAnalogChorus.h

/**************************************************************************//**
 *  @file
 *  @author Steve Lascos
 *  @company Blackaddr Audio
 *
 *  AudioEffectAnalogChorus is a class for simulating a classic BBD based chorus
 *  like the Boss CE-2. This class works with either internal RAM, or external
 *  SPI RAM. The external RAM uses DMA to minimize load on the
 *  CPU.
 *
 *  @copyright This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.*
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *****************************************************************************/

#ifndef __BAEFFECTS_BAAUDIOEFFECTANALOGCHORUS_H
#define __BAEFFECTS_BAAUDIOEFFECTANALOGCHORUS_H

#include <Audio.h>
#include "LibBasicFunctions.h"

namespace BAEffects {

/**************************************************************************//**
 * AudioEffectAnalogChorus models BBD based analog chorus. It provides controls
 * for rate, depth, mix and output level. All parameters can be
 * controlled by MIDI. The class supports internal memory, or external SPI
 * memory by providing an ExtMemSlot. External memory access uses DMA to reduce
 * process load.
 *****************************************************************************/
class AudioEffectAnalogChorus : public AudioStream {
public:

	///< List of AudioEffectAnalogChorus MIDI controllable parameters
	enum {
		BYPASS = 0,  ///<  controls effect bypass
		RATE,        ///< controls the modulate rate of the LFO
		DEPTH,       ///< controls the depth of modulation of the LFO
		MIX,         ///< controls the the mix of input and chorus signals
		VOLUME,      ///< controls the output volume level
		NUM_CONTROLS ///< this can be used as an alias for the number of MIDI controls
	};

	enum class Filter {
        CE2 = 0,
        WARM,
        DARK
	};


    /// Construct an analog chorus using internal memory. The chorus will have the
	/// default average delay.
	AudioEffectAnalogChorus();

	/// Construct an analog chorus using external SPI via an ExtMemSlot. The chorus will have
	/// the default average delay.
	/// @param slot A pointer to the ExtMemSlot to use for the delay.

	virtual ~AudioEffectAnalogChorus(); ///< Destructor

	// *** PARAMETERS ***

	/// Set the chorus average delay in milliseconds
	/// The value should be between 0.0f and 1.0f
	void setDelayConfig(float averageDelayMs, float delayRangeMs);

    /// Set the chorus average delay in number of audio samples
    /// The value should be between 0.0f and 1.0f
    void setDelayConfig(size_t averageDelayNumSamples, size_t delayRangeNumSamples);

	/// Bypass the effect.
	/// @param byp when true, bypass wil disable the effect, when false, effect is enabled.
    /// Note that audio still passes through when bypass is enabled.
	void bypass(bool byp) { m_bypass = byp; }

	/// Get if the effect is bypassed
	/// @returns true if bypassed, false if not bypassed
	bool isBypass() { return m_bypass; }

	/// Toggle the bypass effect
	void toggleBypass() { m_bypass = !m_bypass; }

	/// Set the LFO waveform
	/// @param waveform the LFO waveform to modulate chorus delay with
	void setWaveform(BALibrary::Waveform waveform);

    /// Set the LFO frequency where 0.0f is MIN and 1.0f is MAX
    void rate(float rate);

    /// Set the depth of LFO modulation.
    /// @param lfoDepth must be a float between 0.0f and 1.0f
    void depth(float lfoDepth) { m_lfoDepth = lfoDepth; }

	/// Set the amount of blending between dry and wet (echo) at the output.
	/// @param mix When 0.0, output is 100% dry, when 1.0, output is 100% wet. When
	/// 0.5, output is 50% Dry, 50% Wet.
	void mix(float mix) { m_mix = mix; }

	/// Set the output volume. This affect both the wet and dry signals.
	/// @details The default is 1.0.
	/// @param vol Sets the output volume between -1.0 and +1.0
	void volume(float vol) {m_volume = vol; }

	// ** ENABLE  / DISABLE **

	/// Enables audio processing. Note: when not enabled, CPU load is nearly zero.
	void enable() { m_enable = true; }

	/// Disables audio process. When disabled, CPU load is nearly zero.
	void disable() { m_enable = false; }

	// ** MIDI **

	/// Sets whether MIDI OMNI channel is processig on or off. When on,
	/// all midi channels are used for matching CCs.
	/// @param isOmni when true, all channels are processed, when false, channel
	/// must match configured value.
	void setMidiOmni(bool isOmni) { m_isOmni = isOmni; }

	/// Configure an effect parameter to be controlled by a MIDI CC
	/// number on a particular channel.
	/// @param parameter one of the parameter names in the class enum
	/// @param midiCC the CC number from 0 to 127
	/// @param midiChannel the effect will only response to the CC on this channel
	/// when OMNI mode is off.
	void mapMidiControl(int parameter, int midiCC, int midiChannel = 0);

	/// process a MIDI Continous-Controller (CC) message
	/// @param channel the MIDI channel from 0 to 15)
	/// @param midiCC the CC number from 0 to 127
	/// @param value the CC value from 0 to 127
	void processMidi(int channel, int midiCC, int value);

	// ** FILTER COEFFICIENTS **

	/// Set the filter coefficients to one of the presets. See AudioEffectAnalogChorus::Filter
	/// for options.
	/// @details See AudioEffectAnalogChorusFIlters.h for more details.
	/// @param filter the preset filter. E.g. AudioEffectAnalogChorus::Filter::WARM
	void setFilter(Filter filter);

	/// Override the default coefficients with your own. The number of filters stages affects how
	/// much CPU is consumed.
	/// @details The effect uses the CMSIS-DSP library for biquads which requires coefficents.
	/// be in q31 format, which means they are 32-bit signed integers representing -1.0 to slightly
	/// less than +1.0. The coeffShift parameter effectively multiplies the coefficients by 2^shift. <br>
	/// Example: If you really want +1.5, must instead use +0.75 * 2^1, thus 0.75 in q31 format is
	/// (0.75 * 2^31) = 1610612736 and coeffShift = 1.
	/// @param numStages the actual number of filter stages you want to use. Must be <= MAX_NUM_FILTER_STAGES.
	/// @param coeffs pointer to an integer array of coefficients in q31 format.
	/// @param coeffShift Coefficient scaling factor = 2^coeffShift.
	void setFilterCoeffs(int numStages, const int32_t *coeffs, int coeffShift);

	virtual void update(void); ///< update automatically called by the Teesny Audio Library

private:
	static constexpr float m_DEFAULT_AVERAGE_DELAY_MS = 20.0f; ///< default average delay of chorus in milliseconds
	static constexpr float m_DELAY_RANGE      = 15.0f; ///< default range of delay variation in milliseconds
	static constexpr float m_LFO_MIN_RATE     = 2.0f;  ///< slowest possible LFO rate in milliseconds
	static constexpr float m_LFO_RANGE        = 8.0f;  ///< fastest possible LFO rate in milliseconds

	audio_block_t *m_inputQueueArray[1];
	bool m_isOmni = false;
	bool m_bypass = true;
	bool m_enable = false;
	bool m_externalMemory = false;
	BALibrary::AudioDelay *m_memory = nullptr;
    audio_block_t *m_previousBlock = nullptr;
    audio_block_t *m_blockToRelease  = nullptr;

	BALibrary::LowFrequencyOscillatorVector<float> m_lfo;
	size_t m_maxDelaySamples = 0;
	//size_t m_currentDelayOffset = 0;
	float m_delayRange = 0;

	BALibrary::IirBiQuadFilterHQ *m_iir = nullptr;

	// Controls
	int m_midiConfig[NUM_CONTROLS][2]; // stores the midi parameter mapping
	float m_averageDelaySamples = 0;
	float m_lfoDepth = 0.0f;
	float m_mix = 0.0f;
	float m_volume = 1.0f;

	void m_preProcessing (audio_block_t *out, audio_block_t *dry, audio_block_t *wet);
	void m_postProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet);

	// Coefficients
	void m_constructFilter(void);
};

}

#endif /* __BAEFFECTS_BAAUDIOEFFECTAnalogChorus_H */