HalfedgeMesh.h

//Author: Christian Hafner
#pragma once

#include "AbstractMesh.h"
#include <glm/glm.hpp>
#include <vector>
#include <list>

class SurfaceAlignedParticle;

struct HE_Halfedge;

struct HE_VertexTraits
{
    glm::vec3 position;
};

struct HE_Vertex
{
    HE_Vertex();
    HE_Vertex(const HE_VertexTraits& traits);

    HE_Halfedge* outgoing;
    unsigned index;

    HE_VertexTraits traits;
};

struct HE_Face
{
    HE_Face();

    HE_Halfedge* bounding;
    unsigned index;

    std::list<SurfaceAlignedParticle*> associatedParticles;

    glm::vec3 _normal;
    glm::vec3 normal() const;
};

struct HE_Halfedge
{
    HE_Halfedge();

    HE_Halfedge* prev;
    HE_Halfedge* next;
    HE_Halfedge* opposite;
    HE_Face* face;
    HE_Vertex* toVertex;
    unsigned index;
};

class HalfedgeMesh : public AbstractMesh
{
public:
    HalfedgeMesh();
    virtual ~HalfedgeMesh();

    virtual void init(const MeshDescriptor& descr);

    unsigned halfedgeCount() const;
    unsigned vertexCount() const;
    unsigned faceCount() const;

    bool removeFace(unsigned fi);
    bool removeVertex(unsigned vi);

    HE_Vertex* addVertex(const HE_VertexTraits& traits);
    HE_Face* addFace(unsigned vi1, unsigned vi2, unsigned vi3);
    
    HE_Vertex* vertex(unsigned i);
    HE_Face* face(unsigned i);
    HE_Halfedge* halfedge(unsigned i);

    void convert(AbstractMesh* output, bool computeNormals=false, bool smoothNormals=false) const;

    void consolidate();

private:
    std::vector<HE_Vertex*> _vertices;
    std::vector<HE_Face*> _faces;
    std::vector<HE_Halfedge*> _halfedges;

    std::list<unsigned> _freeVertexIndices;
    std::list<unsigned> _freeFaceIndices;
    std::list<unsigned> _freeHalfedgeIndices;

    unsigned _numHalfedges;
    unsigned _numVertices;
    unsigned _numFaces;

    HE_Halfedge* findHalfedge(HE_Vertex* fromVertex, HE_Vertex* toVertex);
    HE_Halfedge* findOutgoingBoundaryHalfedge(HE_Vertex* vertex);

    void addHalfedgeToList(HE_Halfedge* halfedge);
    void addFaceToList(HE_Face* face);
};