SoundFieldRendering.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "ISoundfieldFormat.h"
#include "DSP/SphericalHarmonicCalculator.h"
#include "DSP/BufferVectorOperations.h"
 
SOUNDFIELDRENDERING_API FName GetUnrealAmbisonicsFormatName();
SOUNDFIELDRENDERING_API TUniquePtr<ISoundfieldDecoderStream> CreateDefaultSourceAmbisonicsDecoder(Audio::FMixerDevice* InDevice);
SOUNDFIELDRENDERING_API ISoundfieldEncodingSettingsProxy& GetAmbisonicsSourceDefaultSettings();
 
 
class FAmbisonicsSoundfieldBuffer : public ISoundfieldAudioPacket
{
public:
    // Interleaved audio buffer for all vector parts of the ambisonics stream.
    Audio::FAlignedFloatBuffer AudioBuffer;
 
    // number of channels in the Ambisonics stream.
    // Currently we don't explicitly support mixed order ambisonics,
    // so this will always be equal to (m + 1)^2, where m is the order  of ambisonics this was encoded with.
    int32 NumChannels;
 
    // This is the rotation of the ambisonics source.
    FQuat Rotation;
    FQuat PreviousRotation;
 
    FAmbisonicsSoundfieldBuffer()
        : NumChannels(0)
        , Rotation(FQuat::Identity)
        , PreviousRotation(FQuat::Identity)
    {}
 
    virtual ~FAmbisonicsSoundfieldBuffer()
    {}
 
    SOUNDFIELDRENDERING_API virtual void Serialize(FArchive& Ar) override;
    SOUNDFIELDRENDERING_API virtual TUniquePtr<ISoundfieldAudioPacket> Duplicate() const override;
    SOUNDFIELDRENDERING_API virtual void Reset() override;
 
};
 
class FAmbisonicsSoundfieldSettings : public ISoundfieldEncodingSettingsProxy
{
public:
    int32 Order;
 
    SOUNDFIELDRENDERING_API virtual uint32 GetUniqueId() const override;
    SOUNDFIELDRENDERING_API virtual TUniquePtr<ISoundfieldEncodingSettingsProxy> Duplicate() const override;
 
};
 
class FSoundFieldDecoder
{
public:
    SOUNDFIELDRENDERING_API FSoundFieldDecoder(); // initializes VirtualSpeakerWorldLockedSpeakerGains
 
    SOUNDFIELDRENDERING_API void DecodeAudioDirectlyToDeviceOutputPositions(const FAmbisonicsSoundfieldBuffer& InputData, const FSoundfieldSpeakerPositionalData& OutputPositions, Audio::FAlignedFloatBuffer& OutputData);
    SOUNDFIELDRENDERING_API void DecodeAudioToSevenOneAndDownmixToDevice(const FAmbisonicsSoundfieldBuffer& InputData, const FSoundfieldSpeakerPositionalData& OutputPositions, Audio::FAlignedFloatBuffer& OutputData);
    static SOUNDFIELDRENDERING_API void RotateFirstOrderAmbisonicsBed(const FAmbisonicsSoundfieldBuffer& InputData, FAmbisonicsSoundfieldBuffer& OutputData, const FQuat& DestinationRotation, const FQuat& PreviousRotation);
 
    static SOUNDFIELDRENDERING_API void FoaRotationInPlace(Audio::FAlignedFloatBuffer& InOutFrames, const float XRotDegrees, const float YRotDegrees, const float ZRotDegrees);
 
private:
    // Special cased, vectorized versions of first order operations.
    static SOUNDFIELDRENDERING_API void FirstOrderDecodeLoop(const int32 NumFrames, const int32 NumOutputChannels, const float* pAmbiFrame, const int32 NumAmbiChannels, float* SpeakerGainsPtr, float* OutputBufferPtrBuffer);
    static SOUNDFIELDRENDERING_API void FirstOrderToSevenOneLoop(const int32 NumFrames, const int32 NumOutputChannels, const float* pAmbiFrame, const int32 NumAmbiChannels, float* SpeakerGainsPtr, float* OutputBufferPtrBuffer);
 
    // Special cased vectorized versions of 3rd and fifth order operations.
    static SOUNDFIELDRENDERING_API void OddOrderDecodeLoop(const int32 NumFrames, const int32 NumOutputChannels, const float* pAmbiFrame, const int32 NumAmbiChannels, float* SpeakerGainsPtr, float* OutputBufferPtrBuffer);
    static SOUNDFIELDRENDERING_API void OddOrderToSevenOneLoop(const int32 NumFrames, const int32 NumOutputChannels, const float* pAmbiFrame, const int32 NumAmbiChannels, float* SpeakerGainsPtr, float* OutputBufferPtrBuffer);
 
    // Partially vectorized decode operations for 2nd and 4th order operations.
    static SOUNDFIELDRENDERING_API void EvenOrderDecodeLoop(const int32 NumFrames, const int32 NumOutputChannels, const float* pAmbiFrame, const int32 NumAmbiChannels, float* SpeakerGainsPtr, float* OutputBufferPtrBuffer);
    static SOUNDFIELDRENDERING_API void EvenOrderToSevenOneLoop(const int32 NumFrames, const int32 NumOutputChannels, const float* pAmbiFrame, const int32 NumAmbiChannels, float* SpeakerGainsPtr, float* OutputBufferPtrBuffer);
 
    // Helper function to get the default channel positions for a channel array.
    static SOUNDFIELDRENDERING_API TArray<Audio::FChannelPositionInfo>* GetDefaultChannelPositions(int32 InNumChannels);
 
    Audio::FAlignedFloatBuffer VirtualSpeakerScratchBuffers;
    Audio::FAlignedFloatBuffer FoaVirtualSpeakerWordLockedGains;
    Audio::FAlignedFloatBuffer TargetSpeakerGains;
    Audio::FAlignedFloatBuffer CurrentSpeakerGains;
    Audio::FAlignedFloatBuffer MixdownGainsMap;
    Audio::FBufferLinearEase SpeakerGainLerper;
    FVector2D LastListenerRotationSphericalCoord{ -999.f, -999.f }; // force interpolation on first callback
 
    static SOUNDFIELDRENDERING_API FSphericalHarmonicCalculator SphereHarmCalc;
    static SOUNDFIELDRENDERING_API TArray<Audio::FChannelPositionInfo> VirtualSpeakerLocationsHorzOnly;
    static SOUNDFIELDRENDERING_API const VectorRegister Sqrt2Over2Vec;
    static SOUNDFIELDRENDERING_API const VectorRegister ZeroVec;
 
    
    friend class FSoundFieldEncoder;
};
 
class FSoundFieldEncoder
{
public:
    SOUNDFIELDRENDERING_API FSoundFieldEncoder();
    SOUNDFIELDRENDERING_API void EncodeAudioDirectlyFromOutputPositions(const Audio::FAlignedFloatBuffer& InputData, const FSoundfieldSpeakerPositionalData& InputPositions, const FAmbisonicsSoundfieldSettings& Settings, FAmbisonicsSoundfieldBuffer& OutputData);
 
private:
    static void EncodeLoop(const int32 NumFrames, const int32 NumInputChannels, const float* RESTRICT InputAudioPtr, const int32 NumAmbiChannels, float* RESTRICT SpeakerGainsPtr, float* RESTRICT OutputAmbiBuffer);
 
    Audio::FAlignedFloatBuffer VirtualSpeakerScratchBuffers;
    Audio::FAlignedFloatBuffer SpeakerGains;
    Audio::FAlignedFloatBuffer MixdownGainsMap;
};