91 lines
2.7 KiB
Text
91 lines
2.7 KiB
Text
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// Copyright 2020 Phyronnaz
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#pragma once
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#include "VoxelUtilities/VoxelDistanceFieldUtilities.h"
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#include "VoxelUtilities/VoxelMathUtilities.h"
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#include "VoxelUtilities/VoxelMiscUtilities.h"
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template<typename T, typename TLambda>
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void FVoxelDistanceFieldUtilities::GetSurfacePositionsFromDensities(
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const FIntVector& Size,
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TArrayView<const T> Densities,
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TArrayView<float> OutDistances,
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TArrayView<FVector3f> OutSurfacePositions,
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TLambda GetFloatFromT)
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{
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VOXEL_ASYNC_FUNCTION_COUNTER();
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const FIntVector DensitiesSize = Size + 2;
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const FIntVector DensitiesOffset = FIntVector(-1, -1, -1);
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check(Densities.Num() == DensitiesSize.X * DensitiesSize.Y * DensitiesSize.Z);
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check(OutDistances.Num() == Size.X * Size.Y * Size.Z);
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check(OutSurfacePositions.Num() == Size.X * Size.Y * Size.Z);
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for (int32 X = 0; X < Size.X; X++)
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{
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for (int32 Y = 0; Y < Size.Y; Y++)
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{
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for (int32 Z = 0; Z < Size.Z; Z++)
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{
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const FIntVector Position(X, Y, Z);
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const float Value = GetFloatFromT(FVoxelUtilities::Get3D(Densities, DensitiesSize, Position, DensitiesOffset));
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const int32 Index = FVoxelUtilities::Get3DIndex(Size, Position);
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FVoxelUtilities::Get(OutDistances, Index) = FMath::Sign(Value);
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// Static branch
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const auto Lambda = [&](auto IsNegative)
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{
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// Take the max: this is the one that will "push" the value the closest to us
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// Only consider positive values, so that there's a surface between us
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// By symmetry, take the min value negative if Value is positive
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float MaxNeighborValue = 0.f;
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FIntVector MaxNeighborPosition;
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#define CheckNeighbor(DX, DY, DZ) \
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{ \
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const FIntVector NeighborPosition = Position + FIntVector(DX, DY, DZ); \
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const float NeighborValue = GetFloatFromT(FVoxelUtilities::Get3D(Densities, DensitiesSize, NeighborPosition, DensitiesOffset)); \
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\
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if (IsNegative ? (NeighborValue > MaxNeighborValue) : (NeighborValue < MaxNeighborValue)) \
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{ \
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MaxNeighborValue = NeighborValue; \
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MaxNeighborPosition = NeighborPosition; \
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} \
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}
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CheckNeighbor(-1, 0, 0);
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CheckNeighbor(+1, 0, 0);
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CheckNeighbor(0, -1, 0);
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CheckNeighbor(0, +1, 0);
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CheckNeighbor(0, 0, -1);
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CheckNeighbor(0, 0, +1);
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#undef CheckNeighbor
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if (MaxNeighborValue == 0.f)
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{
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FVoxelUtilities::Get(OutSurfacePositions, Index) = MakeInvalidSurfacePosition();
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}
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else
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{
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const float Alpha = Value / (Value - MaxNeighborValue);
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FVoxelUtilities::Get(OutSurfacePositions, Index) = FMath::Lerp(FVector3f(Position), FVector3f(MaxNeighborPosition), Alpha);
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}
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};
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if (Value <= 0)
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{
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Lambda(FVoxelUtilities::FTrueType());
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}
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else
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{
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Lambda(FVoxelUtilities::FFalseType());
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}
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}
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}
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}
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}
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