andrewm@0: /*
andrewm@0:   This code accompanies the textbook:
andrewm@0:  
andrewm@0:   Digital Audio Effects: Theory, Implementation and Application
andrewm@0:   Joshua D. Reiss and Andrew P. McPherson
andrewm@0:  
andrewm@0:   ---
andrewm@0:  
andrewm@0:   Wah-Wah: filter effect using variable-frequency filter
andrewm@0:   See textbook Chapter 4: Filter Effects
andrewm@0:  
andrewm@0:   Code by Andrew McPherson, Brecht De Man and Joshua Reiss
andrewm@0:  
andrewm@0:   ---
andrewm@0: 
andrewm@0:   This program is free software: you can redistribute it and/or modify
andrewm@0:   it under the terms of the GNU General Public License as published by
andrewm@0:   the Free Software Foundation, either version 3 of the License, or
andrewm@0:   (at your option) any later version.
andrewm@0:  
andrewm@0:   This program is distributed in the hope that it will be useful,
andrewm@0:   but WITHOUT ANY WARRANTY; without even the implied warranty of
andrewm@0:   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
andrewm@0:   GNU General Public License for more details.
andrewm@0: 
andrewm@0:   You should have received a copy of the GNU General Public License
andrewm@0:   along with this program.  If not, see <http://www.gnu.org/licenses/>.
andrewm@0: */
andrewm@0: 
andrewm@0: #include "PluginProcessor.h"
andrewm@0: #include "PluginEditor.h"
andrewm@0: 
andrewm@0: // The filter will produce a resonant peak of amplitude Q; bring everything
andrewm@0: // down somewhat to compensate, though try to maintain some perceptual balance
andrewm@0: // of being similar loudness. (This factor has been chosen somewhat arbitrarily.)
andrewm@0: const double kWahwahFilterGain = 0.5;
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: WahwahAudioProcessor::WahwahAudioProcessor()
andrewm@0: {
andrewm@0:     // Set default values:
andrewm@0:     centreFrequency_ = 400.0;
andrewm@0:     q_ = 5.0;
andrewm@0:     
andrewm@0:     // Initialise the filters later when we know how many channels
andrewm@0:     wahFilters_ = 0;
andrewm@0:     numWahFilters_ = 0;
andrewm@0:     
andrewm@0:     inverseSampleRate_ = 1.0/44100.0; // start with a sensible default
andrewm@0:     
andrewm@0:     lastUIWidth_ = 370;
andrewm@0:     lastUIHeight_ = 100;
andrewm@0: }
andrewm@0: 
andrewm@0: WahwahAudioProcessor::~WahwahAudioProcessor()
andrewm@0: {
andrewm@0: }
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: const String WahwahAudioProcessor::getName() const
andrewm@0: {
andrewm@0:     return JucePlugin_Name;
andrewm@0: }
andrewm@0: 
andrewm@0: int WahwahAudioProcessor::getNumParameters()
andrewm@0: {
andrewm@0:     return kNumParameters;
andrewm@0: }
andrewm@0: 
andrewm@0: float WahwahAudioProcessor::getParameter (int index)
andrewm@0: {
andrewm@0:     // This method will be called by the host, probably on the audio thread, so
andrewm@0:     // it's absolutely time-critical. Don't use critical sections or anything
andrewm@0:     // UI-related, or anything at all that may block in any way!
andrewm@0:     switch (index)
andrewm@0:     {
andrewm@0:         case kCentreFrequencyParam: return centreFrequency_;
andrewm@0:         case kQParam:               return q_;
andrewm@0:         default:                    return 0.0f;
andrewm@0:     }
andrewm@0: }
andrewm@0: 
andrewm@0: void WahwahAudioProcessor::setParameter (int index, float newValue)
andrewm@0: {
andrewm@0:     // This method will be called by the host, probably on the audio thread, so
andrewm@0:     // it's absolutely time-critical. Don't use critical sections or anything
andrewm@0:     // UI-related, or anything at all that may block in any way!
andrewm@0:     switch (index)
andrewm@0:     {
andrewm@0:         case kCentreFrequencyParam:
andrewm@0:             centreFrequency_ = newValue;
andrewm@0:             updateFilter();
andrewm@0:             break;
andrewm@0:         case kQParam:
andrewm@0:             q_ = newValue;
andrewm@0:             updateFilter();
andrewm@0:             break;
andrewm@0:         default:
andrewm@0:             break;
andrewm@0:     }
andrewm@0: }
andrewm@0: 
andrewm@0: const String WahwahAudioProcessor::getParameterName (int index)
andrewm@0: {
andrewm@0:     switch (index)
andrewm@0:     {
andrewm@0:         case kCentreFrequencyParam:  return "centre frequency";
andrewm@0:         case kQParam:                return "Q";
andrewm@0:         default:                     break;
andrewm@0:     }
andrewm@0:     
andrewm@0:     return String::empty;
andrewm@0: }
andrewm@0: 
andrewm@0: const String WahwahAudioProcessor::getParameterText (int index)
andrewm@0: {
andrewm@0:     return String (getParameter (index), 2);
andrewm@0: }
andrewm@0: 
andrewm@0: const String WahwahAudioProcessor::getInputChannelName (int channelIndex) const
andrewm@0: {
andrewm@0:     return String (channelIndex + 1);
andrewm@0: }
andrewm@0: 
andrewm@0: const String WahwahAudioProcessor::getOutputChannelName (int channelIndex) const
andrewm@0: {
andrewm@0:     return String (channelIndex + 1);
andrewm@0: }
andrewm@0: 
andrewm@0: bool WahwahAudioProcessor::isInputChannelStereoPair (int index) const
andrewm@0: {
andrewm@0:     return true;
andrewm@0: }
andrewm@0: 
andrewm@0: bool WahwahAudioProcessor::isOutputChannelStereoPair (int index) const
andrewm@0: {
andrewm@0:     return true;
andrewm@0: }
andrewm@0: 
andrewm@0: bool WahwahAudioProcessor::silenceInProducesSilenceOut() const
andrewm@0: {
andrewm@0: #if JucePlugin_SilenceInProducesSilenceOut
andrewm@0:     return true;
andrewm@0: #else
andrewm@0:     return false;
andrewm@0: #endif
andrewm@0: }
andrewm@0: 
andrewm@0: double WahwahAudioProcessor::getTailLengthSeconds() const
andrewm@0: {
andrewm@0:     return 0.0;
andrewm@0: }
andrewm@0: 
andrewm@0: bool WahwahAudioProcessor::acceptsMidi() const
andrewm@0: {
andrewm@0: #if JucePlugin_WantsMidiInput
andrewm@0:     return true;
andrewm@0: #else
andrewm@0:     return false;
andrewm@0: #endif
andrewm@0: }
andrewm@0: 
andrewm@0: bool WahwahAudioProcessor::producesMidi() const
andrewm@0: {
andrewm@0: #if JucePlugin_ProducesMidiOutput
andrewm@0:     return true;
andrewm@0: #else
andrewm@0:     return false;
andrewm@0: #endif
andrewm@0: }
andrewm@0: 
andrewm@0: int WahwahAudioProcessor::getNumPrograms()
andrewm@0: {
andrewm@0:     return 0;
andrewm@0: }
andrewm@0: 
andrewm@0: int WahwahAudioProcessor::getCurrentProgram()
andrewm@0: {
andrewm@0:     return 0;
andrewm@0: }
andrewm@0: 
andrewm@0: void WahwahAudioProcessor::setCurrentProgram (int index)
andrewm@0: {
andrewm@0: }
andrewm@0: 
andrewm@0: const String WahwahAudioProcessor::getProgramName (int index)
andrewm@0: {
andrewm@0:     return String::empty;
andrewm@0: }
andrewm@0: 
andrewm@0: void WahwahAudioProcessor::changeProgramName (int index, const String& newName)
andrewm@0: {
andrewm@0: }
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: void WahwahAudioProcessor::prepareToPlay (double sampleRate, int samplesPerBlock)
andrewm@0: {
andrewm@0:     // Use this method as the place to do any pre-playback
andrewm@0:     // initialisation that you need..
andrewm@0:     
andrewm@0:     // Create as many filters as we have input channels
andrewm@0:     numWahFilters_ = getNumInputChannels();
andrewm@0:     wahFilters_ = (ResonantLowpassFilter**)malloc(numWahFilters_ * sizeof(ResonantLowpassFilter*));
andrewm@0:     if(wahFilters_ == 0)
andrewm@0:         numWahFilters_ = 0;
andrewm@0:     else {
andrewm@0:         for(int i = 0; i < numWahFilters_; i++)
andrewm@0:             wahFilters_[i] = new ResonantLowpassFilter;
andrewm@0:     }
andrewm@0:     
andrewm@0:     inverseSampleRate_ = 1.0 / sampleRate;
andrewm@0:     
andrewm@0:     // Update the filter settings to work with the current parameters and sample rate
andrewm@0:     updateFilter();
andrewm@0: }
andrewm@0: 
andrewm@0: void WahwahAudioProcessor::releaseResources()
andrewm@0: {
andrewm@0:     // When playback stops, you can use this as an opportunity to free up any
andrewm@0:     // spare memory, etc.
andrewm@0:     for(int i = 0; i < numWahFilters_; i++)
andrewm@0:         delete wahFilters_[i];
andrewm@0:     if(numWahFilters_ != 0)
andrewm@0:         free(wahFilters_);
andrewm@0:     numWahFilters_ = 0;
andrewm@0:     wahFilters_ = 0;
andrewm@0: }
andrewm@0: 
andrewm@0: void WahwahAudioProcessor::processBlock (AudioSampleBuffer& buffer, MidiBuffer& midiMessages)
andrewm@0: {
andrewm@0:     // Helpful information about this block of samples:
andrewm@0:     const int numInputChannels = getNumInputChannels();     // How many input channels for our effect?
andrewm@0:     const int numOutputChannels = getNumOutputChannels();   // How many output channels for our effect?
andrewm@0:     const int numSamples = buffer.getNumSamples();          // How many samples in the buffer for this block?
andrewm@0:     int channel;
andrewm@0:     
andrewm@0:     // Go through each channel of audio that's passed in
andrewm@0:     
andrewm@0:     for (channel = 0; channel < jmin(numInputChannels, numWahFilters_); ++channel)
andrewm@0:     {
andrewm@0:         // channelData is an array of length numSamples which contains the audio for one channel
b@1:         float* channelData = buffer.getWritePointer(channel);
andrewm@0:      
andrewm@0:         // Run the samples through the IIR filter whose coefficients define the parametric
andrewm@0:         // equaliser. See juce_IIRFilter.cpp for the implementation.
andrewm@0:         wahFilters_[channel]->processSamples(channelData, numSamples);
andrewm@0:     }
andrewm@0:     
andrewm@0:     // Go through the remaining channels. In case we have more outputs
andrewm@0:     // than inputs, or there aren't enough filters, we'll clear any
andrewm@0:     // remaining output channels (which could otherwise contain garbage)
andrewm@0:     while(channel < numOutputChannels)
andrewm@0:     {
andrewm@0:         buffer.clear (channel++, 0, buffer.getNumSamples());
andrewm@0:     }
andrewm@0: }
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: bool WahwahAudioProcessor::hasEditor() const
andrewm@0: {
andrewm@0:     return true; // (change this to false if you choose to not supply an editor)
andrewm@0: }
andrewm@0: 
andrewm@0: AudioProcessorEditor* WahwahAudioProcessor::createEditor()
andrewm@0: {
andrewm@0:     return new WahwahAudioProcessorEditor (this);
andrewm@0: }
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: void WahwahAudioProcessor::getStateInformation (MemoryBlock& destData)
andrewm@0: {
andrewm@0:     // You should use this method to store your parameters in the memory block.
andrewm@0:     // You could do that either as raw data, or use the XML or ValueTree classes
andrewm@0:     // as intermediaries to make it easy to save and load complex data.
andrewm@0:     
andrewm@0:     // Create an outer XML element..
andrewm@0:     XmlElement xml("C4DMPLUGINSETTINGS");
andrewm@0:     
andrewm@0:     // add some attributes to it..
andrewm@0:     xml.setAttribute("uiWidth", lastUIWidth_);
andrewm@0:     xml.setAttribute("uiHeight", lastUIHeight_);
andrewm@0:     xml.setAttribute("centreFrequency", centreFrequency_);
andrewm@0:     xml.setAttribute("q", q_);
andrewm@0:     
andrewm@0:     // then use this helper function to stuff it into the binary blob and return it..
andrewm@0:     copyXmlToBinary(xml, destData);
andrewm@0: }
andrewm@0: 
andrewm@0: void WahwahAudioProcessor::setStateInformation (const void* data, int sizeInBytes)
andrewm@0: {
andrewm@0:     // You should use this method to restore your parameters from this memory block,
andrewm@0:     // whose contents will have been created by the getStateInformation() call.
andrewm@0:     
andrewm@0:     // This getXmlFromBinary() helper function retrieves our XML from the binary blob..
andrewm@0:     ScopedPointer<XmlElement> xmlState (getXmlFromBinary (data, sizeInBytes));
andrewm@0:     
andrewm@0:     if(xmlState != 0)
andrewm@0:     {
andrewm@0:         // make sure that it's actually our type of XML object..
andrewm@0:         if(xmlState->hasTagName("C4DMPLUGINSETTINGS"))
andrewm@0:         {
andrewm@0:             // ok, now pull out our parameters..
andrewm@0:             lastUIWidth_  = xmlState->getIntAttribute("uiWidth", lastUIWidth_);
andrewm@0:             lastUIHeight_ = xmlState->getIntAttribute("uiHeight", lastUIHeight_);
andrewm@0:             
andrewm@0:             q_ = (float)xmlState->getDoubleAttribute("q", q_);
andrewm@0:             centreFrequency_ = (float)xmlState->getDoubleAttribute("centreFrequency", centreFrequency_);
andrewm@0:             inverseSampleRate_ = 1.0 / getSampleRate();
andrewm@0:             updateFilter();
andrewm@0:         }
andrewm@0:     }
andrewm@0: }
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: // Update the coefficients of the resonant lowpass filter
andrewm@0: void WahwahAudioProcessor::updateFilter()
andrewm@0: {
andrewm@0:     for(int i = 0; i < numWahFilters_; i++)
andrewm@0:         wahFilters_[i]->makeResonantLowpass(inverseSampleRate_, centreFrequency_, q_,
andrewm@0:                                             kWahwahFilterGain);
andrewm@0: }
andrewm@0: 
andrewm@0: //==============================================================================
andrewm@0: // This creates new instances of the plugin..
andrewm@0: AudioProcessor* JUCE_CALLTYPE createPluginFilter()
andrewm@0: {
andrewm@0:     return new WahwahAudioProcessor();
andrewm@0: }