EM_Task/UnrealEd/Private/Fbx/AdjacentInfo.h

#pragma once

#include <assert.h>
#include "CoreMinimal.h"

// 邻接顶点
class FAdjacentVertex
{
public:
    FAdjacentVertex(const FAdjacentVertex& Vertex) = default;

    FAdjacentVertex(uint32 index): index(index), inBorder(false), angle(0.0f) {}

    uint32 Index() const { return index; }

    FVector& Pos() { return pos; }

    bool& InBorder() { return inBorder; }

    FVector& Normal() { return normal; }

    FVector& SoftNormal() { return softNormal; }

    float& Angle() { return angle; }

    float Type() const { return type; }

    TArray<FAdjacentVertex*>& AdjVertice() { return adjVertice; }

    void CalculateType();

    void CalculateSoftNormalByAdjVertice();

    void ProjectSoftNormalOnNormalPlane();

private:
    // 此顶点索引
    uint32 index;

    // 顶点位置
    FVector pos;

    // 此顶点是否处于边界位置
    bool inBorder;

    FVector normal;

    // 在边缘的话，软法线指向边界延伸方向
    FVector softNormal;

    // 邻接三角形角度和
    float angle;

    // 0表示非边界点（内部点），1表示普通边界点，2表示angle大于270°的分叉点，3表示angle小于90°的尖端点
    float type;

    TArray<FAdjacentVertex*> adjVertice;
};

bool operator==(const FAdjacentVertex& Left, const FAdjacentVertex& Right);

FORCEINLINE uint32 GetTypeHash(FAdjacentVertex Vertex)
{
    return GetTypeHash(Vertex.Index());
}

// 邻接边
class FAdjacentEdge
{
public:
    FAdjacentEdge(const FAdjacentEdge& Edge) = default;

    FAdjacentEdge(FAdjacentVertex& V1, FAdjacentVertex& V2);

    FAdjacentVertex& V1() { return v1; }

    const FAdjacentVertex& V1() const { return v1; }

    FAdjacentVertex& V2() { return v2; }

    const FAdjacentVertex& V2() const { return v2; }

    float Length() { return length; }

    uint32& Count() { return count; }

    // 设置此边连接的两个顶点位于边界
    void SetInBorder();

    void AddVertexToEdge();

private:
    // 连接的两个顶点
    FAdjacentVertex &v1, &v2;

    float length;

    uint32 count;
};

bool operator==(const FAdjacentEdge& Left, const FAdjacentEdge& Right);

// 顶点相同（顺序可以相反）的边，哈希值相同
FORCEINLINE uint32 GetTypeHash(FAdjacentEdge Edge)
{
    return GetTypeHash(Edge.V1()) + GetTypeHash(Edge.V2());
}

// 邻接多边形
class FAdjacentPolygon
{
public:
    FAdjacentPolygon(const FAdjacentPolygon& Triangle) = default;

    FAdjacentPolygon(const TArray<FAdjacentVertex*>& Vertices, const TArray<FAdjacentEdge*>& Edges, int32 n);

    FAdjacentVertex& V(uint32 i)
    {
        assert(0 <= i && i < n);
        return *v[i];
    }

    FAdjacentEdge& E(uint32 i)
    {
        assert(0 <= i && i < n);
        return *e[i];
    }

    // 计算三角形对每个顶点法线的贡献度
    void CalculateVertexNormal();

private:
    TArray<FAdjacentVertex*> v;

    TArray<FAdjacentEdge*> e;

    int32 n;

    FVector normal;
};