MeshTopologyHelper.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#if PLATFORM_DESKTOP
 
#include "MeshTypes.h"
#include "MeshDescription.h"
 
#include <bit>
 
#define ELEMENT_FIRST_MARKER_MASK   0x02
 
namespace UE::CADKernel::MeshUtilities
{
    struct FElementMetaData
    {
        uint16 Category : 4;
        uint16 Markers : 4;
        uint16 Extras : 4;
    };
 
    enum class EElementType : uint8_t
    {
        Unused       = 0,
        Free         = 1 << 0,
        Line         = 1 << 1,
        Surface      = 1 << 2,
        Border       = 1 << 3,
        NonManifold  = 1 << 4,
        NonSurface   = 1 << 5,
        Max          = 1 << 7,
    };
    ENUM_CLASS_FLAGS(EElementType)
 
    class FMeshTopologyHelper
    {
 
    private:
        FMeshDescription& Mesh;
 
        TArray<EElementType> VertexTypeSet;
        TArray<EElementType> EdgeTypeSet;
 
        TBitArray<> VertexInstanceMarker;
        TBitArray<> TriangleMarkers;
 
    private:
        static int32 type_width(EElementType Type)
        {
            return std::bit_width((unsigned char)Type);
        }
 
    public:
        FMeshTopologyHelper(FMeshDescription& InMeshDescription);
        ~FMeshTopologyHelper();
 
        void UpdateMeshWrapper();
 
        bool IsTriangleMarked(FTriangleID Triangle) const
        {
            return TriangleMarkers[Triangle];
        }
        void SetTriangleMarked(FTriangleID Triangle)
        {
            TriangleMarkers[Triangle] = true;
        }
 
        EElementType GetEdgeType(FEdgeID Edge) const
        {
            return EdgeTypeSet[Edge];
        }
 
        bool IsEdgeOfType(FEdgeID Edge, EElementType Type) const
        {
            return EnumHasAnyFlags(EdgeTypeSet[Edge], Type);
        }
 
        bool IsVertexOfType(FVertexInstanceID Vertex, EElementType Type) const;
 
        // Triangle
        void GetTriangleVertexExtremities(FTriangleID Triangle, FVector& MinCorner, FVector& MaxCorner, FIntVector& HighestVertex, FIntVector& LowestVertex) const;
 
        void SwapTriangleOrientation(FTriangleID Triangle);
 
        // Edge
        const FTriangleID GetOtherTriangleAtEdge(FEdgeID Edge, FTriangleID Triangle) const;
 
        bool GetEdgeDirectionInTriangle(FEdgeID Edge, int32 TriangleIndex) const;
        void DefineEdgeTopology(FEdgeID EdgeID);
 
        // Vertex
        void SwapVertexNormal(FVertexInstanceID VertexID);
        void GetVertexExtremities(FVertexInstanceID Vertex, FVector& MinCorner, FVector& MaxCorner, FIntVector& HighestVertex, FIntVector& LowestVertex) const;
 
        void DefineVertexTopologyApproximation(FVertexID VertexID);
    };
}
#endif