git subrepo clone --branch=sono6good https://github.com/essej/JUCE.git deps/juce
subrepo: subdir: "deps/juce" merged: "b13f9084e" upstream: origin: "https://github.com/essej/JUCE.git" branch: "sono6good" commit: "b13f9084e" git-subrepo: version: "0.4.3" origin: "https://github.com/ingydotnet/git-subrepo.git" commit: "2f68596"
This commit is contained in:
essej
269
deps/juce/modules/juce_audio_basics/utilities/juce_ADSR.h
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deps/juce/modules/juce_audio_basics/utilities/juce_ADSR.h
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/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2020 - Raw Material Software Limited
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JUCE is an open source library subject to commercial or open-source
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licensing.
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The code included in this file is provided under the terms of the ISC license
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http://www.isc.org/downloads/software-support-policy/isc-license. Permission
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To use, copy, modify, and/or distribute this software for any purpose with or
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without fee is hereby granted provided that the above copyright notice and
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this permission notice appear in all copies.
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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A very simple ADSR envelope class.
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To use it, call setSampleRate() with the current sample rate and give it some parameters
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with setParameters() then call getNextSample() to get the envelope value to be applied
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to each audio sample or applyEnvelopeToBuffer() to apply the envelope to a whole buffer.
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@tags{Audio}
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*/
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class JUCE_API ADSR
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{
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public:
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//==============================================================================
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ADSR()
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{
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recalculateRates();
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}
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//==============================================================================
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/**
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Holds the parameters being used by an ADSR object.
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@tags{Audio}
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*/
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struct JUCE_API Parameters
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{
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Parameters() = default;
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Parameters (float attackTimeSeconds,
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float decayTimeSeconds,
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float sustainLevel,
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float releaseTimeSeconds)
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: attack (attackTimeSeconds),
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decay (decayTimeSeconds),
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sustain (sustainLevel),
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release (releaseTimeSeconds)
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{
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}
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float attack = 0.1f, decay = 0.1f, sustain = 1.0f, release = 0.1f;
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};
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/** Sets the parameters that will be used by an ADSR object.
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You must have called setSampleRate() with the correct sample rate before
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this otherwise the values may be incorrect!
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@see getParameters
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*/
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void setParameters (const Parameters& newParameters)
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{
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// need to call setSampleRate() first!
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jassert (sampleRate > 0.0);
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parameters = newParameters;
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recalculateRates();
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}
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/** Returns the parameters currently being used by an ADSR object.
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@see setParameters
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*/
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const Parameters& getParameters() const noexcept { return parameters; }
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/** Returns true if the envelope is in its attack, decay, sustain or release stage. */
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bool isActive() const noexcept { return state != State::idle; }
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//==============================================================================
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/** Sets the sample rate that will be used for the envelope.
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This must be called before the getNextSample() or setParameters() methods.
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*/
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void setSampleRate (double newSampleRate) noexcept
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{
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jassert (newSampleRate > 0.0);
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sampleRate = newSampleRate;
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}
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//==============================================================================
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/** Resets the envelope to an idle state. */
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void reset() noexcept
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{
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envelopeVal = 0.0f;
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state = State::idle;
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}
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/** Starts the attack phase of the envelope. */
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void noteOn() noexcept
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{
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if (attackRate > 0.0f)
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{
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state = State::attack;
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}
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else if (decayRate > 0.0f)
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{
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envelopeVal = 1.0f;
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state = State::decay;
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}
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else
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{
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state = State::sustain;
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}
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}
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/** Starts the release phase of the envelope. */
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void noteOff() noexcept
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{
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if (state != State::idle)
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{
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if (parameters.release > 0.0f)
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{
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releaseRate = (float) (envelopeVal / (parameters.release * sampleRate));
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state = State::release;
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}
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else
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{
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reset();
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}
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}
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}
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//==============================================================================
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/** Returns the next sample value for an ADSR object.
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@see applyEnvelopeToBuffer
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*/
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float getNextSample() noexcept
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{
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if (state == State::idle)
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return 0.0f;
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if (state == State::attack)
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{
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envelopeVal += attackRate;
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if (envelopeVal >= 1.0f)
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{
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envelopeVal = 1.0f;
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goToNextState();
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}
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}
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else if (state == State::decay)
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{
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envelopeVal -= decayRate;
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if (envelopeVal <= parameters.sustain)
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{
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envelopeVal = parameters.sustain;
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goToNextState();
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}
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}
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else if (state == State::sustain)
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{
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envelopeVal = parameters.sustain;
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}
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else if (state == State::release)
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{
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envelopeVal -= releaseRate;
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if (envelopeVal <= 0.0f)
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goToNextState();
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}
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return envelopeVal;
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}
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/** This method will conveniently apply the next numSamples number of envelope values
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to an AudioBuffer.
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@see getNextSample
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*/
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template <typename FloatType>
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void applyEnvelopeToBuffer (AudioBuffer<FloatType>& buffer, int startSample, int numSamples)
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{
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jassert (startSample + numSamples <= buffer.getNumSamples());
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if (state == State::idle)
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{
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buffer.clear (startSample, numSamples);
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return;
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}
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if (state == State::sustain)
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{
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buffer.applyGain (startSample, numSamples, parameters.sustain);
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return;
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}
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auto numChannels = buffer.getNumChannels();
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while (--numSamples >= 0)
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{
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auto env = getNextSample();
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for (int i = 0; i < numChannels; ++i)
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buffer.getWritePointer (i)[startSample] *= env;
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++startSample;
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}
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}
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private:
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//==============================================================================
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void recalculateRates() noexcept
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{
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auto getRate = [] (float distance, float timeInSeconds, double sr)
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{
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return timeInSeconds > 0.0f ? (float) (distance / (timeInSeconds * sr)) : -1.0f;
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};
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attackRate = getRate (1.0f, parameters.attack, sampleRate);
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decayRate = getRate (1.0f - parameters.sustain, parameters.decay, sampleRate);
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releaseRate = getRate (parameters.sustain, parameters.release, sampleRate);
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if ((state == State::attack && attackRate <= 0.0f)
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|| (state == State::decay && (decayRate <= 0.0f || envelopeVal <= parameters.sustain))
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|| (state == State::release && releaseRate <= 0.0f))
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{
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goToNextState();
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}
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}
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void goToNextState() noexcept
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{
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if (state == State::attack)
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state = (decayRate > 0.0f ? State::decay : State::sustain);
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else if (state == State::decay)
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state = State::sustain;
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else if (state == State::release)
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reset();
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}
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//==============================================================================
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enum class State { idle, attack, decay, sustain, release };
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State state = State::idle;
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Parameters parameters;
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double sampleRate = 44100.0;
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float envelopeVal = 0.0f, attackRate = 0.0f, decayRate = 0.0f, releaseRate = 0.0f;
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};
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} // namespace juce
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