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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SYNTHMARK_SIMPLE_VOICE_H
#define SYNTHMARK_SIMPLE_VOICE_H
#include <cstdint>
#include <math.h>
#include "SynthTools.h"
#include "VoiceBase.h"
#include "SawtoothOscillator.h"
#include "SawtoothOscillatorDPW.h"
#include "SquareOscillatorDPW.h"
#include "SineOscillator.h"
#include "EnvelopeADSR.h"
#include "PitchToFrequency.h"
#include "BiquadFilter.h"
namespace marksynth {
/**
* Classic subtractive synthesizer voice with
* 2 LFOs, 2 audio oscillators, filter and envelopes.
*/
class SimpleVoice : public VoiceBase
{
public:
SimpleVoice()
: VoiceBase()
, mLfo1()
, mOsc1()
, mOsc2()
, mPitchToFrequency()
, mFilter()
, mFilterEnvelope()
, mAmplitudeEnvelope()
// The following values are arbitrary but typical values.
, mDetune(1.0001f) // slight phasing
, mVibratoDepth(0.03f)
, mVibratoRate(6.0f)
, mFilterEnvDepth(3000.0f)
, mFilterCutoff(400.0f)
{
mFilter.setQ(2.0);
// Randomize attack times to smooth out CPU load for envelope state transitions.
mFilterEnvelope.setAttackTime(0.05 + (0.2 * SynthTools::nextRandomDouble()));
mFilterEnvelope.setDecayTime(7.0 + (1.0 * SynthTools::nextRandomDouble()));
mAmplitudeEnvelope.setAttackTime(0.02 + (0.05 * SynthTools::nextRandomDouble()));
mAmplitudeEnvelope.setDecayTime(1.0 + (0.2 * SynthTools::nextRandomDouble()));
}
virtual ~SimpleVoice() = default;
void setPitch(synth_float_t pitch) {
mPitch = pitch;
}
void noteOn(synth_float_t pitch, synth_float_t velocity) {
(void) velocity; // TODO use velocity?
mPitch = pitch;
mFilterEnvelope.setGate(true);
mAmplitudeEnvelope.setGate(true);
}
void noteOff() {
mFilterEnvelope.setGate(false);
mAmplitudeEnvelope.setGate(false);
}
void generate(int32_t numFrames) {
assert(numFrames <= kSynthmarkFramesPerRender);
// LFO #1 - vibrato
mLfo1.generate(mVibratoRate, numFrames);
synth_float_t *pitches = mBuffer1;
SynthTools::scaleOffsetBuffer(mLfo1.output, pitches, numFrames, mVibratoDepth, mPitch);
synth_float_t *frequencies = mBuffer2;
mPitchToFrequency.generate(pitches, frequencies, numFrames);
// OSC #1 - sawtooth
mOsc1.generate(frequencies, numFrames);
// OSC #2 - detuned square wave oscillator
SynthTools::scaleBuffer(frequencies, frequencies, numFrames, mDetune);
mOsc2.generate(frequencies, numFrames);
// Mix the two oscillators
synth_float_t *mixed = frequencies;
SynthTools::mixBuffers(mOsc1.output, 0.6, mOsc2.output, 0.4, mixed, numFrames);
// Filter envelope
mFilterEnvelope.generate(numFrames);
synth_float_t *cutoffFrequencies = pitches; // reuse unneeded buffer
SynthTools::scaleOffsetBuffer(mFilterEnvelope.output, cutoffFrequencies, numFrames,
mFilterEnvDepth, mFilterCutoff);
// Biquad resonant low-pass filter
mFilter.generate(mixed, cutoffFrequencies, numFrames);
// Amplitude ADSR
mAmplitudeEnvelope.generate(numFrames);
SynthTools::multiplyBuffers(mFilter.output, mAmplitudeEnvelope.output, output, numFrames);
}
private:
SineOscillator mLfo1;
SawtoothOscillatorDPW mOsc1;
SquareOscillatorDPW mOsc2;
PitchToFrequency mPitchToFrequency;
BiquadFilter mFilter;
EnvelopeADSR mFilterEnvelope;
EnvelopeADSR mAmplitudeEnvelope;
synth_float_t mDetune; // frequency scaler
synth_float_t mVibratoDepth; // in semitones
synth_float_t mVibratoRate; // in Hertz
synth_float_t mFilterEnvDepth; // in Hertz
synth_float_t mFilterCutoff; // in Hertz
// Buffers for storing signals that are being passed between units.
synth_float_t mBuffer1[kSynthmarkFramesPerRender];
synth_float_t mBuffer2[kSynthmarkFramesPerRender];
};
};
#endif // SYNTHMARK_SIMPLE_VOICE_H
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