Analog.h

/* Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Dean Beeler, Jerome Fisher
 * Copyright (C) 2011-2022 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 2.1 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef MT32EMU_ANALOG_H
#define MT32EMU_ANALOG_H

#include "globals.h"
#include "internals.h"
#include "Enumerations.h"
#include "Types.h"

namespace MT32Emu {

/* Analog class is dedicated to perform fair emulation of analogue circuitry of hardware units that is responsible
 * for processing output signal after the DAC. It appears that the analogue circuit labeled "LPF" on the schematic
 * also applies audible changes to the signal spectra. There is a significant boost of higher frequencies observed
 * aside from quite poor attenuation of the mirror spectra above 16 kHz which is due to a relatively low filter order.
 *
 * As the final mixing of multiplexed output signal is performed after the DAC, this function is migrated here from Synth.
 * Saying precisely, mixing is performed within the LPF as the entrance resistors are actually components of a LPF
 * designed using the multiple feedback topology. Nevertheless, the schematic separates them.
 */
class Analog {
public:
    static Analog *createAnalog(const AnalogOutputMode mode, const bool oldMT32AnalogLPF, const RendererType rendererType);

    virtual ~Analog() {}
    virtual unsigned int getOutputSampleRate() const = 0;
    virtual Bit32u getDACStreamsLength(const Bit32u outputLength) const = 0;
    virtual void setSynthOutputGain(const float synthGain) = 0;
    virtual void setReverbOutputGain(const float reverbGain, const bool mt32ReverbCompatibilityMode) = 0;

    virtual bool process(IntSample *outStream, const IntSample *nonReverbLeft, const IntSample *nonReverbRight, const IntSample *reverbDryLeft, const IntSample *reverbDryRight, const IntSample *reverbWetLeft, const IntSample *reverbWetRight, Bit32u outLength) = 0;
    virtual bool process(FloatSample *outStream, const FloatSample *nonReverbLeft, const FloatSample *nonReverbRight, const FloatSample *reverbDryLeft, const FloatSample *reverbDryRight, const FloatSample *reverbWetLeft, const FloatSample *reverbWetRight, Bit32u outLength) = 0;
};

} // namespace MT32Emu

#endif // #ifndef MT32EMU_ANALOG_H