UE4 - DataTable Demo from Exodus

Difficulties.csv

ExodusGameMode.cpp

void AExodusGameMode::InitGameState()
{
	APlanet *planet;
	Super::InitGameState();

	FMath::SRandInit(LevelSeed);

	int remainingResources, resourcesUsed;

	AExodusGameState* const state = Cast<AExodusGameState>(GameState);

	check(state);

	state->SetGameDifficulty(DifficultyString);
	state->OnGameStart();

	NumAutoGeneratedPlanets = state->GetDifficulty()->Planets;
	WorldBounds = state->GetDifficulty()->Bounds;

	remainingResources = state->InitialUniverseResources;
	resourcesUsed = 0;

	for (int i = 0; i < NumAutoGeneratedPlanets; i++)
	{
		planet = CreatePlanet();

		check(planet != NULL);

		planet->SetPlanetName(*PlanetInfo->GetUniqueName());

		state->PlanetsArray.Add(planet);

		if (firstPlanet == NULL)
		{
			resourcesUsed = state->GetDifficulty()->InitialPlanetResources;

			planet->SetPopulation(state->GetDifficulty()->InitialPlanetPopulation);
			planet->SetScale(FMath::Clamp(resourcesUsed * 3.0f / MainPlanetResourcesMax, 1.0f, 2.0f));

			firstPlanet = planet;
		}
		else
		{
			resourcesUsed = FMath::SRand() * FMath::Min(remainingResources, GeneralPlanetResourcesMax);

			planet->SetPopulation(GeneralPlanetPopulation);
			planet->SetScale(FMath::Clamp(resourcesUsed * 2.0f / GeneralPlanetResourcesMax, 1.0f, 2.0f));
		}

		remainingResources -= resourcesUsed;

		planet->SetResources(resourcesUsed);
		planet->EnsureViscinityIsClear(WorldBounds);
	}

	if (remainingResources > 0 && firstPlanet != NULL)
	{
		UE_LOG(Exodus, Log, TEXT("Lost %d resources"), remainingResources);

		for (TActorIterator<APlanet> It(GetWorld()); It; ++It)
		{
			planet = Cast<APlanet>(*It);
			if (planet == firstPlanet)
			{
				continue;
			}

			planet->SetResources(planet->GetResources() + remainingResources / (NumAutoGeneratedPlanets - 1));
		}
	}

	AddGameEvent(TEXT("The exodus begins! The battle for the survival of the human race has started."), GetWorld()->TimeSeconds, this);
}

ExodusGameState.cpp

AExodusGameState::AExodusGameState(const class FPostConstructInitializeProperties& PCIP) : Super(PCIP)
{
	[ ... ]

	Difficulties = Objects::Get<UDataTable>(TEXT("DataTable'/Game/Data/Difficulty.Difficulty'"));

	DifficultyString = "Easy";
}

[ ... ]

void AExodusGameState::SetGameDifficulty(FString difficultyString) 
{
	DifficultyString = difficultyString;
}

FDifficulty *AExodusGameState::GetDifficulty()
{
	FDifficulty* result;
	result = Difficulties->FindRow<FDifficulty>(*DifficultyString, TEXT("Difficulty"));

	// If the difficulty is not found, create an empty one
	if (!result)
	{
		UE_LOG(Exodus, Warning, TEXT("Couldn't load difficulty - >%s<"), *DifficultyString);
		result = new FDifficulty();
	}

	check(result);

	return result;
}

ExodusGameState.h

UCLASS(config = Exodus)
class AExodusGameState : public AGameState
{
	void SetGameDifficulty(FString DifficultyString);
	
	FDifficulty *GetDifficulty();

	UDataTable*  Difficulties;
	FString DifficultyString;
}

ExodusTypes.h

/// Difficulty Object
USTRUCT(BlueprintType)
struct FDifficulty : public FTableRowBase
{
	GENERATED_USTRUCT_BODY()

public: 
	FDifficulty()
		: InitialUniverseResources(100000)
		, InitialUniversePopulation(4000)
		, InitialPlanetPopulation(400)
		, InitialPlanetResources(1200)
		, Planets(10)
		, Bounds(1024)
		, ResourceConsumptionRate(0.0005f)
		, OrbitScale(1.8)
		, LaunchTimer(5.0f)
		, PopulationTimer(5.0f)
		, ResourcesTimer(5.0f)
		, LowPopulationGrowthRate(0.012f)
		, HighPopulationGrowthRate(-0.042f)
		, EvenPopulationGrowthRate(0.001f)
		, NoResourcesGrowthRate(-0.3f)
		, LowPopulationRatio(0.5f)
		, EvenPopulationRatio(0.7f)
		, OrbitTime(15)
		, MaxOrbits(5)
		, LaunchVelocity(136)
		, DeepSpace(1536)
		, CargoSpace(250)
		, CrewMinimum(50)
		, Gravitation(1.8f)
	{
	}

	/// Game State
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	int32 Planets;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	int32 Bounds;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	int32 InitialPlanetPopulation;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	int32 InitialPlanetResources;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	int32 InitialUniverseResources;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	int32 InitialUniversePopulation;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float ResourceConsumptionRate; 

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float OrbitScale;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float LaunchTimer;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float PopulationTimer;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float ResourcesTimer;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float LowPopulationGrowthRate;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float HighPopulationGrowthRate;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float EvenPopulationGrowthRate;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float NoResourcesGrowthRate;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float LowPopulationRatio;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float EvenPopulationRatio;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float OrbitTime;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float MaxOrbits;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float LaunchVelocity;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float DeepSpace;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float CargoSpace;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float CrewMinimum;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GameDifficulty)
	float Gravitation;
};