Added multi-bus support for audio plug-in clients

examples/PlugInSamples/Spatializer/Source/Spatializer.cpp

@@ -0,0 +1,177 @@
+/*
+ ==============================================================================
+
+ Spatializer.cpp
+ Created: 23 Nov 2015 3:08:33pm
+ Author:  Fabian Renn
+
+ ==============================================================================
+ */
+
+#include "../JuceLibraryCode/JuceHeader.h"
+#include "../../GenericEditor.h"
+
+//==============================================================================
+/**
+ */
+class Spatializer  : public AudioProcessor
+{
+public:
+
+    struct SpeakerPosition
+    {
+        float radius, phi;
+    };
+
+    struct SpeakerLayout
+    {
+        AudioChannelSet set;
+        Array<SpeakerPosition> positions;
+    };
+
+    // this needs at least c++11
+    static Array<SpeakerLayout> speakerPositions;
+
+    //==============================================================================
+    Spatializer() : currentSpeakerLayout (0)
+    {
+        // clear the default bus arrangements which were created by the base class
+        busArrangement.inputBuses .clear();
+        busArrangement.outputBuses.clear();
+
+        // add mono in and default out
+        busArrangement.inputBuses .add (AudioProcessorBus ("Input",  AudioChannelSet::mono()));
+        busArrangement.outputBuses.add (AudioProcessorBus ("Output", speakerPositions[currentSpeakerLayout].set));
+
+        addParameter (radius = new AudioParameterFloat ("radius", "Radius", 0.0f, 1.0f, 0.5f));
+        addParameter (phi    = new AudioParameterFloat ("phi",    "Phi",    0.0f, 1.0f, 0.0f));
+    }
+
+    ~Spatializer() {}
+
+    //==============================================================================
+    bool setPreferredBusArrangement (bool isInputBus, int busIndex,
+                                     const AudioChannelSet& preferred) override
+    {
+        // we only allow mono in
+        if (isInputBus && preferred != AudioChannelSet::mono())
+            return false;
+
+        // the output must be one of the supported speaker layouts
+        if (! isInputBus)
+        {
+            int i;
+
+            for (i = 0; i < speakerPositions.size(); ++i)
+                if (speakerPositions[i].set == preferred) break;
+
+            if (i >= speakerPositions.size())
+                return false;
+
+            currentSpeakerLayout = i;
+        }
+
+        return AudioProcessor::setPreferredBusArrangement (isInputBus, busIndex, preferred);
+    }
+
+    //==============================================================================
+    void prepareToPlay (double sampleRate, int samplesPerBlock) override
+    {
+        scratchBuffer.setSize (1, samplesPerBlock);
+    }
+
+    void releaseResources() override {}
+
+    void processBlock (AudioSampleBuffer& buffer, MidiBuffer&) override
+    {
+        // copy the input into a scratch buffer
+        AudioSampleBuffer scratch (scratchBuffer.getArrayOfWritePointers(), 1, buffer.getNumSamples());
+        scratch.copyFrom(0, 0, buffer, 0, 0, buffer.getNumSamples());
+
+        const Array<SpeakerPosition>& positions = speakerPositions.getReference (currentSpeakerLayout).positions;
+        const float* inputBuffer  = scratch.getReadPointer (0);
+        const float kMaxDistanceGain = -20.0f;
+
+        for (int speakerIdx = 0; speakerIdx < positions.size(); ++speakerIdx)
+        {
+            const SpeakerPosition& speakerPos = positions.getReference (speakerIdx);
+            float fltDistance = distance (polarToCartesian (speakerPos.radius, speakerPos.phi), polarToCartesian (*radius, (*phi) * 2.0f * float_Pi));
+            float gainInDb = kMaxDistanceGain * (fltDistance / 2.0f);
+            float gain = std::pow (10.0f, (gainInDb / 20.0f));
+
+            busArrangement.getBusBuffer(buffer, false, 0).copyFrom(speakerIdx, 0, inputBuffer, buffer.getNumSamples(), gain);
+        }
+    }
+
+    //==============================================================================
+    AudioProcessorEditor* createEditor() override { return new GenericEditor (*this); }
+    bool hasEditor() const override               { return true;   }
+
+    //==============================================================================
+    const String getName() const override               { return "Gain PlugIn"; }
+
+    bool acceptsMidi() const override                   { return false; }
+    bool producesMidi() const override                  { return false; }
+    bool silenceInProducesSilenceOut() const override   { return true; }
+    double getTailLengthSeconds() const override        { return 0; }
+
+    //==============================================================================
+    int getNumPrograms() override                          { return 1; }
+    int getCurrentProgram() override                       { return 0; }
+    void setCurrentProgram (int) override                  {}
+    const String getProgramName (int) override             { return String(); }
+    void changeProgramName (int , const String& ) override { }
+
+    //==============================================================================
+    void getStateInformation (MemoryBlock& destData) override
+    {
+        MemoryOutputStream stream (destData, true);
+
+        stream.writeFloat (*radius);
+        stream.writeFloat (*phi);
+    }
+
+    void setStateInformation (const void* data, int sizeInBytes) override
+    {
+        MemoryInputStream stream (data, sizeInBytes, false);
+
+        radius->setValueNotifyingHost (stream.readFloat());
+        phi->setValueNotifyingHost (stream.readFloat());
+    }
+
+private:
+    //==============================================================================
+    AudioParameterFloat* radius;
+    AudioParameterFloat* phi;
+    int currentSpeakerLayout;
+    AudioSampleBuffer scratchBuffer;
+
+    static Point<float> polarToCartesian (float r, float phi) noexcept
+    {
+        return Point<float> (r * std::cos (phi), r * std::sin (phi));
+    }
+
+    static float distance (Point<float> a, Point<float> b) noexcept
+    {
+        return std::sqrt (std::pow (a.x - b.x, 2.0f) + std::pow (a.y - b.y, 2.0f));
+    }
+
+    //==============================================================================
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Spatializer)
+};
+
+// this needs at least c++11
+Array<Spatializer::SpeakerLayout> Spatializer::speakerPositions =
+{
+    Spatializer::SpeakerLayout { AudioChannelSet::stereo(),         { SpeakerPosition { 1.0f, -0.25f * float_Pi }, SpeakerPosition { 1.0f, 0.25f * float_Pi } }},
+    Spatializer::SpeakerLayout { AudioChannelSet::quadraphonic(),   { SpeakerPosition { 1.0f, -0.25f * float_Pi }, SpeakerPosition { 1.0f, 0.25f * float_Pi }, SpeakerPosition {1.0f, -0.75f * float_Pi}, SpeakerPosition {1.0f, 0.75f * float_Pi}}},
+    Spatializer::SpeakerLayout { AudioChannelSet::create5point0(),  {SpeakerPosition { 1.0f, 0.0f}, SpeakerPosition { 1.0f, -0.25f * float_Pi }, SpeakerPosition { 1.0f, 0.25f * float_Pi }, SpeakerPosition {1.0f, -0.75f * float_Pi}, SpeakerPosition {1.0f, 0.75f * float_Pi}}}
+};
+
+
+//==============================================================================
+// This creates new instances of the plugin..
+AudioProcessor* JUCE_CALLTYPE createPluginFilter()
+{
+    return new Spatializer();
+}