LocalPlanarSimplify.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
// Port of geometry3Sharp MeshPlaneCut
 
#pragma once
 
#include "MathUtil.h"
#include "VectorTypes.h"
#include "GeometryTypes.h"
#include "DynamicMesh/InfoTypes.h"
 
 
namespace UE
{
namespace Geometry
{
 
class FDynamicMesh3;
 
 
//
// Class to support local planar simplification, to reduce excess edges created by plane cuts, edge loop insertions, and similar operations
// (Note a custom version of this logic also exists on the FMeshBoolean class)
//
class FLocalPlanarSimplify
{
public:
    // Simplification settings
 
    double SimplificationAngleTolerance = .1;
    double TryToImproveTriQualityThreshold = .25;
    bool bPreserveTriangleGroups = true;
    bool bPreserveVertexUVs = true;
    bool bPreserveOverlayUVs = true;
    float UVDistortTolerance = FMathf::ZeroTolerance;
    bool bPreserveVertexNormals = true;
    float NormalDistortTolerance = .01f;
 
 
    GEOMETRYCORE_API void SimplifyAlongEdges(FDynamicMesh3& Mesh, TSet<int32>& InOutEdges, TUniqueFunction<void(const DynamicMeshInfo::FEdgeCollapseInfo&)> ProcessCollapse = nullptr) const;
 
    GEOMETRYCORE_API static void CollapseDegenerateEdges(FDynamicMesh3& Mesh, TSet<int32>& InOutEdges, bool bRemoveAllDegenerateFromInputSet = false,
        double DegenerateEdgeLenTol = UE_DOUBLE_SMALL_NUMBER, TSet<int>* TriangleSelection = nullptr);
 
 
    //
    // The below helper functions are used by SimplifyAlongEdges, but also the similar customized versions of the same algorithm in FMeshBoolean and FMeshSelfUnion as well
    //
 
    static GEOMETRYCORE_API bool IsFlat(const FDynamicMesh3& Mesh, int VID, double DotTolerance, FVector3d& OutFirstNormal);
 
    static GEOMETRYCORE_API bool IsDevelopableAlongEdge(const FDynamicMesh3& Mesh, int EID, int VID, double DotTolerance, FVector3d& NormalA, bool& bIsFlat);
 
    static GEOMETRYCORE_API bool CollapseWouldHurtTriangleQuality(
        const FDynamicMesh3& Mesh, const FVector3d& RemoveVNormal,
        int32 RemoveV, const FVector3d& RemoveVPos, int32 KeepV, const FVector3d& KeepVPos,
        double TryToImproveTriQualityThreshold, bool bHasMultipleNormals = false
    );
 
    static GEOMETRYCORE_API bool CollapseWouldChangeShapeOrUVs(
        const FDynamicMesh3& Mesh, const TSet<int>& PathEdgeSet, double DotTolerance, int SourceEID,
        int32 RemoveV, const FVector3d& RemoveVPos, int32 KeepV, const FVector3d& KeepVPos,
        const FVector3d& EdgeDir, bool bPreserveTriangleGroups, bool bPreserveUVsForMesh,
        bool bPreserveVertexUVs, bool bPreserveOverlayUVs, float UVToleranceSq,
        bool bPreserveVertexNormals, float NormalEqualCosThreshold);
 
};
 
} // end namespace UE::Geometry
} // end namespace UE