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Split terrain generation into a parallel task for each slice of const…
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…ant Y.
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@AndrewScheidecker
AndrewScheidecker committed Jun 19, 2015
1 parent 7442afd commit 3d35b0c
Showing 1 changed file with 58 additions and 50 deletions.
108 changes: 58 additions & 50 deletions ...TerrainGeneration/Source/BrickTerrainGeneration/Private/BrickTerrainGenerationLibrary.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -91,73 +91,81 @@ void UBrickTerrainGenerationLibrary::InitRegion(const FBrickTerrainGenerationPar

const FInt3 MinRegionBrickCoordinates = RegionCoordinates * BricksPerRegion;
const FInt3 MaxRegionBrickCoordinates = MinRegionBrickCoordinates + BricksPerRegion - FInt3::Scalar(1);
FGraphEventArray YSliceCompletionEvents;
for(int32 LocalY = 0;LocalY < BricksPerRegion.Y;++LocalY)
{
for(int32 LocalX = 0;LocalX < BricksPerRegion.X;++LocalX)
// Create a task for each slice of constant Y.
YSliceCompletionEvents.Add(FFunctionGraphTask::CreateAndDispatchWhenReady([&,LocalY]()
{
const int32 X = MinRegionBrickCoordinates.X + LocalX;
const int32 Y = MinRegionBrickCoordinates.Y + LocalY;
const float Erosion = LocalErosionFunction.Sample2D(BiasedSeed * 59 + X,Y);
const float UnerodedGroundHeight = LocalUnerodedHeightFunction.Sample2D(BiasedSeed * 67 + X,Y) * NoiseToLocalScale;
const float ErodedGroundHeight = LocalErodedHeightFunction.Sample2D(BiasedSeed * 71 + X,Y) * NoiseToLocalScale;
const float RockHeight = FMath::Lerp(UnerodedGroundHeight,ErodedGroundHeight,Erosion);
const float BaseDirtThickness = LocalDirtThicknessFunction.Sample2D(BiasedSeed * 79 + X,Y) * NoiseToLocalScale;
const float DirtThicknessFactor = Parameters.DirtThicknessFactorByHeight->FloatCurve.Eval(RockHeight * LocalToWorldScale);
const float DirtThickness = FMath::Max(0.0f,BaseDirtThickness * DirtThicknessFactor);
const float GroundHeight = RockHeight + DirtThickness;

const int32 BrickRockHeight = FMath::Min(MaxRegionBrickCoordinates.Z,FPlatformMath::CeilToInt(RockHeight));
const int32 BrickGroundHeight = FMath::Min(MaxRegionBrickCoordinates.Z,FPlatformMath::CeilToInt(GroundHeight));

float CavernProbabilitySamples[BrickGridConstants::MaxBricksPerRegionAxis];
const uint32 NumCavernProbabilitySamples = FMath::Min(BrickGridConstants::MaxBricksPerRegionAxis >> 2,(BrickGroundHeight + 3) >> 2);
float PreviousCavernProbabilitySample = LocalCavernProbabilityFunction.Sample3D(BiasedSeed * 73 + X,Y,MinRegionBrickCoordinates.Z - 1);
for(uint32 CavernSampleIndex = 0;CavernSampleIndex < NumCavernProbabilitySamples;++CavernSampleIndex)
for(int32 LocalX = 0;LocalX < BricksPerRegion.X;++LocalX)
{
const uint32 LocalZ = CavernSampleIndex << 2;
const float NextCavernProbabilitySample = LocalCavernProbabilityFunction.Sample3D(BiasedSeed * 73 + X,Y,MinRegionBrickCoordinates.Z + LocalZ + 3);
CavernProbabilitySamples[LocalZ + 0] = FMath::Lerp(PreviousCavernProbabilitySample,NextCavernProbabilitySample,1.0f / 4.0f);
CavernProbabilitySamples[LocalZ + 1] = FMath::Lerp(PreviousCavernProbabilitySample,NextCavernProbabilitySample,2.0f / 4.0f);
CavernProbabilitySamples[LocalZ + 2] = FMath::Lerp(PreviousCavernProbabilitySample,NextCavernProbabilitySample,3.0f / 4.0f);
CavernProbabilitySamples[LocalZ + 3] = NextCavernProbabilitySample;
PreviousCavernProbabilitySample = NextCavernProbabilitySample;
}

for(int32 LocalZ = 0;LocalZ < BricksPerRegion.Z;++LocalZ)
{
const int32 Z = MinRegionBrickCoordinates.Z + LocalZ;
const FInt3 BrickCoordinates(X,Y,Z);
int32 MaterialIndex = 0;
if(Z == Grid->MinBrickCoordinates.Z)
const int32 X = MinRegionBrickCoordinates.X + LocalX;
const int32 Y = MinRegionBrickCoordinates.Y + LocalY;
const float Erosion = LocalErosionFunction.Sample2D(BiasedSeed * 59 + X,Y);
const float UnerodedGroundHeight = LocalUnerodedHeightFunction.Sample2D(BiasedSeed * 67 + X,Y) * NoiseToLocalScale;
const float ErodedGroundHeight = LocalErodedHeightFunction.Sample2D(BiasedSeed * 71 + X,Y) * NoiseToLocalScale;
const float RockHeight = FMath::Lerp(UnerodedGroundHeight,ErodedGroundHeight,Erosion);
const float BaseDirtThickness = LocalDirtThicknessFunction.Sample2D(BiasedSeed * 79 + X,Y) * NoiseToLocalScale;
const float DirtThicknessFactor = Parameters.DirtThicknessFactorByHeight->FloatCurve.Eval(RockHeight * LocalToWorldScale);
const float DirtThickness = FMath::Max(0.0f,BaseDirtThickness * DirtThicknessFactor);
const float GroundHeight = RockHeight + DirtThickness;

const int32 BrickRockHeight = FMath::Min(MaxRegionBrickCoordinates.Z,FPlatformMath::CeilToInt(RockHeight));
const int32 BrickGroundHeight = FMath::Min(MaxRegionBrickCoordinates.Z,FPlatformMath::CeilToInt(GroundHeight));

float CavernProbabilitySamples[BrickGridConstants::MaxBricksPerRegionAxis];
const uint32 NumCavernProbabilitySamples = FMath::Min(BrickGridConstants::MaxBricksPerRegionAxis >> 2,(BrickGroundHeight + 3) >> 2);
float PreviousCavernProbabilitySample = LocalCavernProbabilityFunction.Sample3D(BiasedSeed * 73 + X,Y,MinRegionBrickCoordinates.Z - 1);
for(uint32 CavernSampleIndex = 0;CavernSampleIndex < NumCavernProbabilitySamples;++CavernSampleIndex)
{
MaterialIndex = Parameters.BottomMaterialIndex;
const uint32 LocalZ = CavernSampleIndex << 2;
const float NextCavernProbabilitySample = LocalCavernProbabilityFunction.Sample3D(BiasedSeed * 73 + X,Y,MinRegionBrickCoordinates.Z + LocalZ + 3);
CavernProbabilitySamples[LocalZ + 0] = FMath::Lerp(PreviousCavernProbabilitySample,NextCavernProbabilitySample,1.0f / 4.0f);
CavernProbabilitySamples[LocalZ + 1] = FMath::Lerp(PreviousCavernProbabilitySample,NextCavernProbabilitySample,2.0f / 4.0f);
CavernProbabilitySamples[LocalZ + 2] = FMath::Lerp(PreviousCavernProbabilitySample,NextCavernProbabilitySample,3.0f / 4.0f);
CavernProbabilitySamples[LocalZ + 3] = NextCavernProbabilitySample;
PreviousCavernProbabilitySample = NextCavernProbabilitySample;
}
else if(Z <= BrickGroundHeight)

for(int32 LocalZ = 0;LocalZ < BricksPerRegion.Z;++LocalZ)
{
const float CavernProbability = CavernProbabilitySamples[LocalZ];
const float RockCavernThreshold = Parameters.CavernThresholdByHeight->FloatCurve.Eval(Z * LocalToWorldScale);
if(Z <= BrickRockHeight)
const int32 Z = MinRegionBrickCoordinates.Z + LocalZ;
const FInt3 BrickCoordinates(X,Y,Z);
int32 MaterialIndex = 0;
if(Z == Grid->MinBrickCoordinates.Z)
{
if(CavernProbability > RockCavernThreshold)
{
MaterialIndex = Parameters.RockMaterialIndex;
}
MaterialIndex = Parameters.BottomMaterialIndex;
}
else
else if(Z <= BrickGroundHeight)
{
if(CavernProbability > RockCavernThreshold + Parameters.DirtCavernThresholdBias)
const float CavernProbability = CavernProbabilitySamples[LocalZ];
const float RockCavernThreshold = Parameters.CavernThresholdByHeight->FloatCurve.Eval(Z * LocalToWorldScale);
if(Z <= BrickRockHeight)
{
if(CavernProbability > RockCavernThreshold)
{
MaterialIndex = Parameters.RockMaterialIndex;
}
}
else
{
MaterialIndex = Z == BrickGroundHeight && LocalMoistureFunction.Sample2D(BiasedSeed * 61 + X,Y) > Parameters.GrassMoistureThreshold
? Parameters.GrassMaterialIndex
: Parameters.DirtMaterialIndex;
if(CavernProbability > RockCavernThreshold + Parameters.DirtCavernThresholdBias)
{
MaterialIndex = Z == BrickGroundHeight && LocalMoistureFunction.Sample2D(BiasedSeed * 61 + X,Y) > Parameters.GrassMoistureThreshold
? Parameters.GrassMaterialIndex
: Parameters.DirtMaterialIndex;
}
}
}
LocalBrickMaterials[((LocalY * BricksPerRegion.X) + LocalX) * BricksPerRegion.Z + LocalZ] = MaterialIndex;
}
LocalBrickMaterials[((LocalY * BricksPerRegion.X) + LocalX) * BricksPerRegion.Z + LocalZ] = MaterialIndex;
}
}
}, TStatId(), NULL));
}

// Wait for all the YSlice tasks to complete.
FTaskGraphInterface::Get().WaitUntilTasksComplete(YSliceCompletionEvents,ENamedThreads::GameThread);

Grid->SetBrickMaterialArray(MinRegionBrickCoordinates,MaxRegionBrickCoordinates,LocalBrickMaterials);

UE_LOG(LogStats,Log,TEXT("UBrickTerrainGenerationLibrary::InitRegion took %fms"),1000.0f * float(FPlatformTime::Seconds() - StartTime));
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