Hi, am I wrong or the tailOff doesn’t work in the Build a MIDI synthesizer demo?
I’ve followed the tutorial and if I change the tail value to 1.0 in the startNote method, the sound plays only a tic…
You shouldn’t be modifying the tailOff
value in startNote()
. If you want to change the length of the tail off then you need to modify the value that it is multiplied by in renderNextBlock()
- for a shorter tail off multiply it by a value closer to 0 and for a longer tail off multiply it by a value closer to 1.0.
Ok, but how can I modify the tailOff private member from the MainComponent in the sliderValueChanged()?
You should use the slider to control the value that tailOff
is multiplied by instead of modifying tailOff
directly.
Ok, but how can I do that from the MainComponent?
My problem is to access a private member or the multiplier of the class SineWaveVoice.h from the MainComponent.cpp
I’ve tried to make a setter method and call it from Main with
SineWaveVoice::setTailOff(release.getValue());
But setTailOff isn’t a static method
You need some way of setting the factor that the tailOff
is multiplied by, either by passing a reference to your MainContentComponent
down to the SineWaveVoice
class where it can get the value in the renderNextBlock
method or by setting the value directly when the slider moves in your MainContentComponent
. Here’s a really simple example of the latter:
/*
==============================================================================
This file is part of the JUCE tutorials.
Copyright (c) 2017 - ROLI Ltd.
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.
THE SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES,
WHETHER EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR
PURPOSE, ARE DISCLAIMED.
==============================================================================
*/
/*******************************************************************************
The block below describes the properties of this PIP. A PIP is a short snippet
of code that can be read by the Projucer and used to generate a JUCE project.
BEGIN_JUCE_PIP_METADATA
name: SynthUsingMidiInputTutorial
version: 1.0.0
vendor: JUCE
website: http://juce.com
description: Synthesiser with midi input.
dependencies: juce_audio_basics, juce_audio_devices, juce_audio_formats,
juce_audio_processors, juce_audio_utils, juce_core,
juce_data_structures, juce_events, juce_graphics,
juce_gui_basics, juce_gui_extra
exporters: xcode_mac, vs2017, linux_make
type: Component
mainClass: MainContentComponent
useLocalCopy: 1
END_JUCE_PIP_METADATA
*******************************************************************************/
#pragma once
//==============================================================================
struct SineWaveSound : public SynthesiserSound
{
SineWaveSound() {}
bool appliesToNote (int) override { return true; }
bool appliesToChannel (int) override { return true; }
};
//==============================================================================
struct SineWaveVoice : public SynthesiserVoice
{
SineWaveVoice() {}
bool canPlaySound (SynthesiserSound* sound) override
{
return dynamic_cast<SineWaveSound*> (sound) != nullptr;
}
void startNote (int midiNoteNumber, float velocity,
SynthesiserSound*, int /*currentPitchWheelPosition*/) override
{
currentAngle = 0.0;
level = velocity * 0.15;
tailOff = 0.0;
auto cyclesPerSecond = MidiMessage::getMidiNoteInHertz (midiNoteNumber);
auto cyclesPerSample = cyclesPerSecond / getSampleRate();
angleDelta = cyclesPerSample * 2.0 * MathConstants<double>::pi;
}
void stopNote (float /*velocity*/, bool allowTailOff) override
{
if (allowTailOff)
{
if (tailOff == 0.0)
tailOff = 1.0;
}
else
{
clearCurrentNote();
angleDelta = 0.0;
}
}
void pitchWheelMoved (int) override {}
void controllerMoved (int, int) override {}
void renderNextBlock (AudioSampleBuffer& outputBuffer, int startSample, int numSamples) override
{
if (angleDelta != 0.0)
{
if (tailOff > 0.0) // [7]
{
while (--numSamples >= 0)
{
auto currentSample = (float) (std::sin (currentAngle) * level * tailOff);
for (auto i = outputBuffer.getNumChannels(); --i >= 0;)
outputBuffer.addSample (i, startSample, currentSample);
currentAngle += angleDelta;
++startSample;
tailOff *= tailOffAmount; // [8]
if (tailOff <= 0.05)
{
clearCurrentNote(); // [9]
angleDelta = 0.0;
break;
}
}
}
else
{
while (--numSamples >= 0) // [6]
{
auto currentSample = (float) (std::sin (currentAngle) * level);
for (auto i = outputBuffer.getNumChannels(); --i >= 0;)
outputBuffer.addSample (i, startSample, currentSample);
currentAngle += angleDelta;
++startSample;
}
}
}
}
double tailOffAmount = 0.99;
private:
double currentAngle = 0.0, angleDelta = 0.0, level = 0.0, tailOff = 0.0;
};
//==============================================================================
class SynthAudioSource : public AudioSource
{
public:
SynthAudioSource (MidiKeyboardState& keyState)
: keyboardState (keyState)
{
for (auto i = 0; i < 4; ++i) // [1]
synth.addVoice (new SineWaveVoice());
synth.addSound (new SineWaveSound()); // [2]
}
void setUsingSineWaveSound()
{
synth.clearSounds();
}
void prepareToPlay (int /*samplesPerBlockExpected*/, double sampleRate) override
{
synth.setCurrentPlaybackSampleRate (sampleRate); // [3]
}
void releaseResources() override {}
void getNextAudioBlock (const AudioSourceChannelInfo& bufferToFill) override
{
bufferToFill.clearActiveBufferRegion();
MidiBuffer incomingMidi;
keyboardState.processNextMidiBuffer (incomingMidi, bufferToFill.startSample,
bufferToFill.numSamples, true); // [4]
synth.renderNextBlock (*bufferToFill.buffer, incomingMidi,
bufferToFill.startSample, bufferToFill.numSamples); // [5]
}
void setTailOffAmount (double to)
{
for (int i = 0; i < synth.getNumVoices(); ++i)
if (auto* v = dynamic_cast<SineWaveVoice*> (synth.getVoice (i)))
v->tailOffAmount = to;
}
private:
MidiKeyboardState& keyboardState;
Synthesiser synth;
};
//==============================================================================
class MainContentComponent : public AudioAppComponent,
private Timer
{
public:
MainContentComponent()
: synthAudioSource (keyboardState),
keyboardComponent (keyboardState, MidiKeyboardComponent::horizontalKeyboard)
{
addAndMakeVisible (keyboardComponent);
tailOffSlider.setSkewFactor (5.0);
tailOffSlider.setRange (0.99, 1.0, 0.0000001);
addAndMakeVisible (tailOffSlider);
tailOffSlider.onValueChange = [this] { synthAudioSource.setTailOffAmount (tailOffSlider.getValue()); };
setAudioChannels (0, 2);
setSize (600, 160);
startTimer (400);
}
~MainContentComponent()
{
shutdownAudio();
}
void resized() override
{
auto bounds = getLocalBounds().reduced (5);
tailOffSlider.setBounds (bounds.removeFromTop (30));
bounds.removeFromTop (5);
keyboardComponent.setBounds (bounds);
}
void prepareToPlay (int samplesPerBlockExpected, double sampleRate) override
{
synthAudioSource.prepareToPlay (samplesPerBlockExpected, sampleRate);
}
void getNextAudioBlock (const AudioSourceChannelInfo& bufferToFill) override
{
synthAudioSource.getNextAudioBlock (bufferToFill);
}
void releaseResources() override
{
synthAudioSource.releaseResources();
}
private:
void timerCallback() override
{
keyboardComponent.grabKeyboardFocus();
stopTimer();
}
//==========================================================================
SynthAudioSource synthAudioSource;
MidiKeyboardState keyboardState;
MidiKeyboardComponent keyboardComponent;
Slider tailOffSlider;
JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (MainContentComponent)
};
Thanks a lot! That works great! (But I can’t understand why in the constructor of SineWaveVoice, the tailOff is set to 0.0, and in the renderNextBlock the if statement of
if (tailOff > 0.0) {...}
runs like the tailOff is major of 0.0 )
The code enclosed in the if (tailOff > 0.0)
block will only be executed when the note has been released and allowTailOff
is true (see the code in the stopNote()
method). It multiplies the level of the sample by a decaying value to simulate a release envelope.
Ah ha!! Thanks, I understand now: the tailOff is set to 1.0 in the stopNote()…
I didn’t saw this…
And if I want to add an attack parameter? How can I calculate the attackMultiplier?
I think I have to do something like that:
void renderNextBlock (AudioSampleBuffer& outputBuffer, int startSample, int numSamples) override
{
if (angleDelta != 0.0)
{
if (tailOff > 0.0)
{
while (--numSamples >= 0)
{
auto currentSample = (float) (std::sin (currentAngle) * level * tailOff);
for (auto i = outputBuffer.getNumChannels(); --i >= 0;)
outputBuffer.addSample(i, startSample, currentSample);
currentAngle += angleDelta;
++startSample;
tailOff *= tailOffAmount;
if (tailOff <= 0.005)
{
clearCurrentNote();
angleDelta = 0.0;
break;
}
}
}
else
{
while (--numSamples >= 0)
{
auto currentSample = (float) (std::sin (currentAngle) * level * attack); // [1] Multiply the amplitude by an attack value
for (auto i = outputBuffer.getNumChannels(); --i >= 0;)
outputBuffer.addSample(i, startSample, currentSample);
currentAngle += angleDelta;
++startSample;
attack *= attackAmount; // [2] multiply the attack value per an attack amount
}
}
}
}
Isn’t it?