AudioBus.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "CoreMinimal.h"
#include "UObject/Object.h"
#include "IAudioProxyInitializer.h"
#include "AudioBus.generated.h"
 
class FAudioDevice;
 
// The number of channels to mix audio into the source bus
UENUM(BlueprintType)
enum class EAudioBusChannels : uint8
{
    Mono = 0,
    Stereo = 1,
    Quad = 3,
    FivePointOne = 5 UMETA(DisplayName = "5.1"),
    SevenPointOne = 7 UMETA(DisplayName = "7.1"),
    MaxChannelCount = 8
};
 
namespace AudioBusUtils
{
    static EAudioBusChannels ConvertIntToEAudioBusChannels(const int32 InValue)
    {
        switch (InValue)
        {
        case 1: return EAudioBusChannels::Mono;
        case 2: return EAudioBusChannels::Stereo;
        case 4: return EAudioBusChannels::Quad;
        case 6: return EAudioBusChannels::FivePointOne;
        case 8: return EAudioBusChannels::SevenPointOne;
        default:
            // TODO alex.perez: LogAudio undeclared identifier, is it ok to add the header that has LogAudio, or should we move this function to another place?
            //UE_LOG(LogAudio, Error, TEXT("Number of channels: %d not available in AudioBusChannels configurations. Make sure that the number of channels used is 1, 2, 4, 6 or 8."), InValue);
            check(false);
            return EAudioBusChannels::Mono;
        }
    };
}
 
class FAudioBusProxy;
 
using FAudioBusProxyPtr = TSharedPtr<FAudioBusProxy, ESPMode::ThreadSafe>;
class FAudioBusProxy final : public Audio::TProxyData<FAudioBusProxy>
{
public:
    IMPL_AUDIOPROXY_CLASS(FAudioBusProxy);
 
    ENGINE_API explicit FAudioBusProxy(UAudioBus* InAudioBus);
 
    FAudioBusProxy(const FAudioBusProxy& Other) = default;
 
    virtual ~FAudioBusProxy() override {}
 
    uint32 AudioBusId = uint32(INDEX_NONE);
    int32 NumChannels = INDEX_NONE;
 
    friend inline uint32 GetTypeHash(const FAudioBusProxy& InProxy)
    {
        return InProxy.TypeHash;
    }
 
private: 
    uint32 TypeHash = uint32(INDEX_NONE);
};
 
// Function to retrieve an audio bus buffer given a handle
// static float* GetAudioBusBuffer(const FAudioBusHandle& AudioBusHandle);
 
// An audio bus is an object which represents an audio patch cord. Audio can be sent to it. It can be sonified using USoundSourceBuses.
// Instances of the audio bus are created in the audio engine. 
UCLASS(ClassGroup = Sound, meta = (BlueprintSpawnableComponent), MinimalAPI)
class UAudioBus : public UObject, public IAudioProxyDataFactory
{
    GENERATED_UCLASS_BODY()
 
public:
 
    UPROPERTY(EditAnywhere, Category = BusProperties)
    EAudioBusChannels AudioBusChannels = EAudioBusChannels::Mono;
 
    //~ Begin UObject
    ENGINE_API virtual void BeginDestroy() override;
    //~ End UObject
 
    // Returns the number of channels of the audio bus in integer format
    int32 GetNumChannels() const { return (int32)AudioBusChannels + 1; }
 
    //~ Begin UObject Interface.
#if WITH_EDITOR
    ENGINE_API virtual void PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent) override;
#endif // WITH_EDITOR
    //~ End UObject Interface.
 
    //~ Begin IAudioProxy Interface
    ENGINE_API virtual TSharedPtr<Audio::IProxyData> CreateProxyData(const Audio::FProxyDataInitParams& InitParams) override;
    //~ End IAudioProxy Interface
};