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ADSR: Minor refactoring, added some tests

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ed 2021-03-29 09:20:05 +01:00
parent 9e64736519
commit 675d93315f
3 changed files with 332 additions and 64 deletions
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4
modules/juce_audio_basics/juce_audio_basics.cpp
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@ -86,3 +86,7 @@
#include "sources/juce_ReverbAudioSource.cpp"
#include "sources/juce_ToneGeneratorAudioSource.cpp"
#include "synthesisers/juce_Synthesiser.cpp"
#if JUCE_UNIT_TESTS
#include "utilities/juce_ADSR_test.cpp"
#endif

149
modules/juce_audio_basics/utilities/juce_ADSR.h
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@ -33,14 +33,13 @@ namespace juce
@tags{Audio}
*/
class ADSR
class JUCE_API ADSR
{
public:
//==============================================================================
ADSR()
{
setSampleRate (44100.0);
setParameters ({});
recalculateRates();
}
//==============================================================================
@ -49,19 +48,22 @@ public:
@tags{Audio}
*/
struct Parameters
struct JUCE_API Parameters
{
/** Attack time in seconds. */
float attack = 0.1f;
Parameters() = default;
/** Decay time in seconds. */
float decay = 0.1f;
Parameters (float attackTimeSeconds,
float decayTimeSeconds,
float sustainLevel,
float releaseTimeSeconds)
: attack (attackTimeSeconds),
decay (decayTimeSeconds),
sustain (sustainLevel),
release (releaseTimeSeconds)
{
}
/** Sustain level. */
float sustain = 1.0f;
/** Release time in seconds. */
float release = 0.1f;
float attack = 0.1f, decay = 0.1f, sustain = 1.0f, release = 0.1f;
};
/** Sets the parameters that will be used by an ADSR object.
@ -73,70 +75,68 @@ public:
*/
void setParameters (const Parameters& newParameters)
{
currentParameters = newParameters;
// need to call setSampleRate() first!
jassert (sampleRate > 0.0);
sustainLevel = newParameters.sustain;
calculateRates (newParameters);
if (currentState != State::idle)
checkCurrentState();
parameters = newParameters;
recalculateRates();
}
/** Returns the parameters currently being used by an ADSR object.
@see setParameters
*/
const Parameters& getParameters() const { return currentParameters; }
const Parameters& getParameters() const noexcept { return parameters; }
/** Returns true if the envelope is in its attack, decay, sustain or release stage. */
bool isActive() const noexcept { return currentState != State::idle; }
bool isActive() const noexcept { return state != State::idle; }
//==============================================================================
/** Sets the sample rate that will be used for the envelope.
This must be called before the getNextSample() or setParameters() methods.
*/
void setSampleRate (double sampleRate)
void setSampleRate (double newSampleRate) noexcept
{
jassert (sampleRate > 0.0);
sr = sampleRate;
jassert (newSampleRate > 0.0);
sampleRate = newSampleRate;
}
//==============================================================================
/** Resets the envelope to an idle state. */
void reset()
void reset() noexcept
{
envelopeVal = 0.0f;
currentState = State::idle;
state = State::idle;
}
/** Starts the attack phase of the envelope. */
void noteOn()
void noteOn() noexcept
{
if (attackRate > 0.0f)
{
currentState = State::attack;
state = State::attack;
}
else if (decayRate > 0.0f)
{
envelopeVal = 1.0f;
currentState = State::decay;
state = State::decay;
}
else
{
currentState = State::sustain;
state = State::sustain;
}
}
/** Starts the release phase of the envelope. */
void noteOff()
void noteOff() noexcept
{
if (currentState != State::idle)
if (state != State::idle)
{
if (currentParameters.release > 0.0f)
if (parameters.release > 0.0f)
{
releaseRate = static_cast<float> (envelopeVal / (currentParameters.release * sr));
currentState = State::release;
releaseRate = (float) (envelopeVal / (parameters.release * sampleRate));
state = State::release;
}
else
{
@ -150,45 +150,41 @@ public:
@see applyEnvelopeToBuffer
*/
float getNextSample()
float getNextSample() noexcept
{
if (currentState == State::idle)
if (state == State::idle)
return 0.0f;
if (currentState == State::attack)
if (state == State::attack)
{
envelopeVal += attackRate;
if (envelopeVal >= 1.0f)
{
envelopeVal = 1.0f;
if (decayRate > 0.0f)
currentState = State::decay;
else
currentState = State::sustain;
goToNextState();
}
}
else if (currentState == State::decay)
else if (state == State::decay)
{
envelopeVal -= decayRate;
if (envelopeVal <= sustainLevel)
if (envelopeVal <= parameters.sustain)
{
envelopeVal = sustainLevel;
currentState = State::sustain;
envelopeVal = parameters.sustain;
goToNextState();
}
}
else if (currentState == State::sustain)
else if (state == State::sustain)
{
envelopeVal = sustainLevel;
envelopeVal = parameters.sustain;
}
else if (currentState == State::release)
else if (state == State::release)
{
envelopeVal -= releaseRate;
if (envelopeVal <= 0.0f)
reset();
goToNextState();
}
return envelopeVal;
@ -204,6 +200,18 @@ public:
{
jassert (startSample + numSamples <= buffer.getNumSamples());
if (state == State::idle)
{
buffer.clear (startSample, numSamples);
return;
}
if (state == State::sustain)
{
buffer.applyGain (startSample, numSamples, parameters.sustain);
return;
}
auto numChannels = buffer.getNumChannels();
while (--numSamples >= 0)
@ -219,30 +227,43 @@ public:
private:
//==============================================================================
void calculateRates (const Parameters& parameters)
void recalculateRates() noexcept
{
// need to call setSampleRate() first!
jassert (sr > 0.0);
auto getRate = [] (float distance, float timeInSeconds, double sr)
{
return timeInSeconds > 0.0f ? (float) (distance / (timeInSeconds * sr)) : -1.0f;
};
attackRate = (parameters.attack > 0.0f ? static_cast<float> (1.0f / (parameters.attack * sr)) : -1.0f);
decayRate = (parameters.decay > 0.0f ? static_cast<float> ((1.0f - sustainLevel) / (parameters.decay * sr)) : -1.0f);
attackRate = getRate (1.0f, parameters.attack, sampleRate);
decayRate = getRate (1.0f - parameters.sustain, parameters.decay, sampleRate);
releaseRate = getRate (parameters.sustain, parameters.release, sampleRate);
if ((state == State::attack && attackRate <= 0.0f)
|| (state == State::decay && (decayRate <= 0.0f || envelopeVal <= parameters.sustain))
|| (state == State::release && releaseRate <= 0.0f))
{
goToNextState();
}
}
void checkCurrentState()
void goToNextState() noexcept
{
if (currentState == State::attack && attackRate <= 0.0f) currentState = decayRate > 0.0f ? State::decay : State::sustain;
else if (currentState == State::decay && decayRate <= 0.0f) currentState = State::sustain;
else if (currentState == State::release && releaseRate <= 0.0f) reset();
if (state == State::attack)
state = (decayRate > 0.0f ? State::decay : State::sustain);
else if (state == State::decay)
state = State::sustain;
else if (state == State::release)
reset();
}
//==============================================================================
enum class State { idle, attack, decay, sustain, release };
State currentState = State::idle;
Parameters currentParameters;
State state = State::idle;
Parameters parameters;
double sr = 0.0;
float envelopeVal = 0.0f, sustainLevel = 0.0f, attackRate = 0.0f, decayRate = 0.0f, releaseRate = 0.0f;
double sampleRate = 44100.0;
float envelopeVal = 0.0f, attackRate = 0.0f, decayRate = 0.0f, releaseRate = 0.0f;
};
} // namespace juce

243
modules/juce_audio_basics/utilities/juce_ADSR_test.cpp Normal file
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@ -0,0 +1,243 @@
/*
==============================================================================
This file is part of the JUCE library.
Copyright (c) 2020 - Raw Material Software Limited
JUCE is an open source library subject to commercial or open-source
licensing.
The code included in this file is provided under the terms of the ISC license
http://www.isc.org/downloads/software-support-policy/isc-license. Permission
To use, copy, modify, and/or distribute this software for any purpose with or
without fee is hereby granted provided that the above copyright notice and
this permission notice appear in all copies.
JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
DISCLAIMED.
==============================================================================
*/
namespace juce
{
struct ADSRTests : public UnitTest
{
ADSRTests() : UnitTest ("ADSR", UnitTestCategories::audio) {}
void runTest() override
{
constexpr double sampleRate = 44100.0;
const ADSR::Parameters parameters { 0.1f, 0.1f, 0.5f, 0.1f };
ADSR adsr;
adsr.setSampleRate (sampleRate);
adsr.setParameters (parameters);
beginTest ("Idle");
{
adsr.reset();
expect (! adsr.isActive());
expectEquals (adsr.getNextSample(), 0.0f);
}
beginTest ("Attack");
{
adsr.reset();
adsr.noteOn();
expect (adsr.isActive());
auto buffer = getTestBuffer (sampleRate, parameters.attack);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isIncreasing (buffer));
}
beginTest ("Decay");
{
adsr.reset();
adsr.noteOn();
advanceADSR (adsr, roundToInt (parameters.attack * sampleRate));
auto buffer = getTestBuffer (sampleRate, parameters.decay);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isDecreasing (buffer));
}
beginTest ("Sustain");
{
adsr.reset();
adsr.noteOn();
advanceADSR (adsr, roundToInt ((parameters.attack + parameters.decay + 0.01) * sampleRate));
auto random = getRandom();
for (int numTests = 0; numTests < 100; ++numTests)
{
const auto sustainLevel = random.nextFloat();
const auto sustainLength = random.nextFloat();
adsr.setParameters ({ parameters.attack, parameters.decay, sustainLevel, parameters.release });
auto buffer = getTestBuffer (sampleRate, sustainLength);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isSustained (buffer, sustainLevel));
}
}
beginTest ("Release");
{
adsr.reset();
adsr.noteOn();
advanceADSR (adsr, roundToInt ((parameters.attack + parameters.decay) * sampleRate));
adsr.noteOff();
auto buffer = getTestBuffer (sampleRate, parameters.release);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isDecreasing (buffer));
}
beginTest ("Zero-length attack jumps to decay");
{
adsr.reset();
adsr.setParameters ({ 0.0f, parameters.decay, parameters.sustain, parameters.release });
adsr.noteOn();
auto buffer = getTestBuffer (sampleRate, parameters.decay);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isDecreasing (buffer));
}
beginTest ("Zero-length decay jumps to sustain");
{
adsr.reset();
adsr.setParameters ({ parameters.attack, 0.0f, parameters.sustain, parameters.release });
adsr.noteOn();
advanceADSR (adsr, roundToInt (parameters.attack * sampleRate));
adsr.getNextSample();
expectEquals (adsr.getNextSample(), parameters.sustain);
auto buffer = getTestBuffer (sampleRate, 1);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isSustained (buffer, parameters.sustain));
}
beginTest ("Zero-length attack and decay jumps to sustain");
{
adsr.reset();
adsr.setParameters ({ 0.0f, 0.0f, parameters.sustain, parameters.release });
adsr.noteOn();
expectEquals (adsr.getNextSample(), parameters.sustain);
auto buffer = getTestBuffer (sampleRate, 1);
adsr.applyEnvelopeToBuffer (buffer, 0, buffer.getNumSamples());
expect (isSustained (buffer, parameters.sustain));
}
beginTest ("Zero-length release resets to idle");
{
adsr.reset();
adsr.setParameters ({ parameters.attack, parameters.decay, parameters.sustain, 0.0f });
adsr.noteOn();
advanceADSR (adsr, roundToInt ((parameters.attack + parameters.decay) * sampleRate));
adsr.noteOff();
expect (! adsr.isActive());
}
}
static void advanceADSR (ADSR& adsr, int numSamplesToAdvance)
{
while (--numSamplesToAdvance >= 0)
adsr.getNextSample();
}
static AudioBuffer<float> getTestBuffer (double sampleRate, float lengthInSeconds)
{
AudioBuffer<float> buffer { 2, roundToInt (lengthInSeconds * sampleRate) };
for (int channel = 0; channel < buffer.getNumChannels(); ++channel)
for (int sample = 0; sample < buffer.getNumSamples(); ++sample)
buffer.setSample (channel, sample, 1.0f);
return buffer;
}
static bool isIncreasing (const AudioBuffer<float>& b)
{
jassert (b.getNumChannels() > 0 && b.getNumSamples() > 0);
for (int channel = 0; channel < b.getNumChannels(); ++channel)
{
float previousSample = -1.0f;
for (int sample = 0; sample < b.getNumSamples(); ++sample)
{
const auto currentSample = b.getSample (channel, sample);
if (currentSample <= previousSample)
return false;
previousSample = currentSample;
}
}
return true;
}
static bool isDecreasing (const AudioBuffer<float>& b)
{
jassert (b.getNumChannels() > 0 && b.getNumSamples() > 0);
for (int channel = 0; channel < b.getNumChannels(); ++channel)
{
float previousSample = std::numeric_limits<float>::max();
for (int sample = 0; sample < b.getNumSamples(); ++sample)
{
const auto currentSample = b.getSample (channel, sample);
if (currentSample >= previousSample)
return false;
previousSample = currentSample;
}
}
return true;
}
static bool isSustained (const AudioBuffer<float>& b, float sustainLevel)
{
jassert (b.getNumChannels() > 0 && b.getNumSamples() > 0);
for (int channel = 0; channel < b.getNumChannels(); ++channel)
if (b.findMinMax (channel, 0, b.getNumSamples()) != Range<float> { sustainLevel, sustainLevel })
return false;
return true;
}
};
static ADSRTests adsrTests;
} // namespace juce