Unreal 4 script which handles music playback by adding functionality to UAudioComponent as a child class

MusicPlayerComponent.cpp

#include "Tacopocalypse.h"
#include "MusicTrackData.h"
#include "TacoSingleton.h"
#include "Engine.h"
#include "SoundDefinitions.h"
#include "MusicPlayerComponent.h"


// Sets default values for this component's properties
UMusicPlayerComponent::UMusicPlayerComponent()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	bWantsBeginPlay = true;
	PrimaryComponentTick.bCanEverTick = true;
	//bIsMusic = true;

	//Load the music database which stores the locations of all of the music tracks
	UMusicTrackData* LoadedMusicDatabase;
	FString MusicDatabasePath = "/Game/TacoContent/Sound/Music/MusicTracksData.MusicTracksData";
	LoadedMusicDatabase = Cast<UMusicTrackData>(StaticLoadObject(UMusicTrackData::StaticClass(), NULL, *MusicDatabasePath, NULL, LOAD_None, NULL));
	NumSongs = LoadedMusicDatabase->SongList.Num();

}


// Called when the game starts
void UMusicPlayerComponent::BeginPlay()
{
	Super::BeginPlay();
}


// Called every frame
void UMusicPlayerComponent::TickComponent( float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction )
{
	Super::TickComponent( DeltaTime, TickType, ThisTickFunction );

	//Checking to see if no music is playing, but music is available to play
	//Sometimes music will refuse to play if not loaded asyncronously fast enough, this is a failsafe
	if (IsLoadingMusic && LoadedSong != nullptr && IsPlaying() == false && this->Sound != nullptr)
	{
		GEngine->AddOnScreenDebugMessage(-1, 1.0f, FColor::Red, TEXT("Trying to play because currently no song is playing -- may not have loaded in time"));
		UE_LOG(LogTemp, Log, TEXT("Trying to play because currently no song is playing -- may not have loaded in time"));
		Play();
		OnMusicLoadedDelegate.Broadcast(LoadedSong);
		IsLoadingMusic = false;
	}
	else if (!IsLoadingMusic && LoadedSong != nullptr && IsPlaying() == false && this->Sound != nullptr)
	{
		OnMusicFinishedPlaybackDelegate.Broadcast();
		GEngine->AddOnScreenDebugMessage(-1, 1.0f, FColor::Red, TEXT("Music finished playing"));
		UE_LOG(LogTemp, Log, TEXT("Music finished playing"));
	}
	else if (IsLoadingMusic && IsPlaying() == true)
	{
		IsLoadingMusic = false;
	}
}

//Load the music Asyncronously, and then call BroadcastMusicLoaded() once loading has completed
void UMusicPlayerComponent::LoadMusic(int32 Index)
{
	TArray<FStringAssetReference> ObjToLoad;
	UMusicTrackData* LoadedMusicDatabase;
	FStreamableManager& BaseLoader = UTacoSingleton::GetSingleton().AssetLoader;

	FString MusicDatabasePath = "/Game/TacoContent/Sound/Music/MusicTracksData.MusicTracksData";

	LoadedMusicDatabase = Cast<UMusicTrackData>(StaticLoadObject(UMusicTrackData::StaticClass(), NULL, *MusicDatabasePath, NULL, LOAD_None, NULL));

	//If our music database is valid, and the index requested falls within the song list array, load the given song
	if (LoadedMusicDatabase != NULL && LoadedMusicDatabase->SongList.Num() > Index)
	{
		MusicAssetToLoad = LoadedMusicDatabase->SongList[Index].MusicResource.ToStringReference();
		LoadedSongName = LoadedMusicDatabase->SongList[Index].ReturnFullName();
		ObjToLoad.AddUnique(MusicAssetToLoad);
	}

	IsLoadingMusic = true;

	//NOTE -- Asyncronous loading currently not working, temporarily using syncronous load to ensure music is loading in time for playback (as of 5/19/16)
	//Assign the event to be called once loading has finished
	//BaseLoader.RequestAsyncLoad(ObjToLoad, FStreamableDelegate::CreateUObject(this, &UMusicPlayerComponent::BroadcastMusicLoaded));

	BaseLoader.SynchronousLoad(ObjToLoad[0]);
	BroadcastMusicLoaded();
}

//Broadcast the music finished loading event to the player blueprint and therefore it's HUD
void UMusicPlayerComponent::BroadcastMusicLoaded()
{
	//Ensure that the music has in fact been loaded
	if (MusicAssetToLoad.ResolveObject() != nullptr)
	{
		UObject* NewMusic = MusicAssetToLoad.ResolveObject();
		LoadedSong = Cast<USoundCue>(NewMusic);

		//Assign the sound to the audio component
		//SetSound() will automatically play the new song if another song is currently playing
		SetSound(LoadedSong);

		//Play if not playing
		if (!IsPlaying())
		{
			Play();
		}

		//Finally broadcast the blueprint event
		OnMusicLoadedDelegate.Broadcast(LoadedSong);
		//IsLoadingMusic = false;
	}
}