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UnrealEngine/Engine/Source/Runtime/MeshUtilitiesCommon/Public/MeshUtilitiesCommon.h
Brandyn / Techy fcc1b09210 init
2026-04-04 15:40:51 -05:00

127 lines
3.2 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "CoreMinimal.h"
enum class ELightmapUVVersion : int32
{
BitByBit = 0,
Segments = 1,
SmallChartPacking = 2,
ScaleChartsOrderingFix = 3,
ChartJoiningLFix = 4,
Allocator2DFlipFix = 5,
ConsiderLightmapPadding = 6,
ForceLightmapPadding = 7,
Segments2D = 8,
OptimalSurfaceArea = 9,
ScaleByEdgesLength = 10,
Latest = ScaleByEdgesLength
};
/**
* Contains the vertices that are most dominated by that bone. Vertices are in Bone space.
* Not used at runtime, but useful for fitting physics assets etc.
*/
struct FBoneVertInfo
{
// Invariant: Arrays should be same length!
TArray<FVector3f> Positions;
TArray<FVector3f> Normals;
};
/** Helper struct for building acceleration structures. */
struct FIndexAndZ
{
float Z;
int32 Index;
/** Default constructor. */
FIndexAndZ() {}
/** Initialization constructor. */
FIndexAndZ(int32 InIndex, FVector3f V)
{
Z = 0.30f * V.X + 0.33f * V.Y + 0.37f * V.Z;
Index = InIndex;
}
};
/** Sorting function for vertex Z/index pairs. */
struct FCompareIndexAndZ
{
inline bool operator()(FIndexAndZ const& A, FIndexAndZ const& B) const { return A.Z < B.Z; }
};
/**
* Returns true if the specified points are about equal
*/
inline bool PointsEqual(const FVector3f& V1, const FVector3f& V2, float ComparisonThreshold)
{
if (FMath::Abs(V1.X - V2.X) > ComparisonThreshold
|| FMath::Abs(V1.Y - V2.Y) > ComparisonThreshold
|| FMath::Abs(V1.Z - V2.Z) > ComparisonThreshold)
{
return false;
}
return true;
}
namespace TriangleUtilities
{
/*
* This function compute the area of a triangle, it will return zero if the triangle is degenerated
*/
static float ComputeTriangleArea(const FVector3f& PointA, const FVector3f& PointB, const FVector3f& PointC)
{
return FVector3f::CrossProduct((PointB - PointA), (PointC - PointA)).Size() / 2.0f;
}
/*
* This function compute the angle of a triangle corner, it will return zero if the triangle is degenerated
*/
static float ComputeTriangleCornerAngle(const FVector3f& PointA, const FVector3f& PointB, const FVector3f& PointC)
{
FVector3f E1 = (PointB - PointA);
FVector3f E2 = (PointC - PointA);
//Normalize both edges (unit vector) of the triangle so we get a dotProduct result that will be a valid acos input [-1, 1]
if (!E1.Normalize() || !E2.Normalize())
{
//Return a null ratio if the polygon is degenerate
return 0.0f;
}
float DotProduct = FVector3f::DotProduct(E1, E2);
return FMath::Acos(DotProduct);
}
}
/**
* [Frisvad 2012, "Building an Orthonormal Basis from a 3D Unit Vector Without Normalization"]
*/
inline FMatrix44f GetTangentBasisFrisvad(FVector3f TangentZ)
{
FVector3f TangentX;
FVector3f TangentY;
if (TangentZ.Z < -0.9999999f)
{
TangentX = FVector3f(0, -1, 0);
TangentY = FVector3f(-1, 0, 0);
}
else
{
float A = 1.0f / (1.0f + TangentZ.Z);
float B = -TangentZ.X * TangentZ.Y * A;
TangentX = FVector3f(1.0f - TangentZ.X * TangentZ.X * A, B, -TangentZ.X);
TangentY = FVector3f(B, 1.0f - TangentZ.Y * TangentZ.Y * A, -TangentZ.Y);
}
FMatrix44f LocalBasis;
LocalBasis.SetIdentity();
LocalBasis.SetAxis(0, TangentX);
LocalBasis.SetAxis(1, TangentY);
LocalBasis.SetAxis(2, TangentZ);
return LocalBasis;
}