MeshCompiler.hh

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#pragma once

#include "VertexDeclaration.hh"

#include <map>
#include <vector>
#include <cstdio>
#include <string>
#include <fstream>

#include <ACG/GL/gl.hh>

/*

Mesh buffer assembler:

Builds a pair of vertex and index buffer based on a poly mesh.


- flexible processing pipeline
- uses index mapping only -> lower memory consumption
- independent of OpenMesh, OpenGL
- 



usage

1. Create a vertex declaration to specify your wanted
   vertex format, such as float3 pos, float3 normal..

2. Set your vertex data.
   Example in (float3 pos, float3 normal, float2 texc) format:
   
   float VertexPositions[100*3] = {..};
   float VertexNormals[120*3] = {..};
   float VertexUV[80*2] = {..};

   drawMesh->setVertices(100, VertexPositions, 12);
   drawMesh->setNormals(120, VertexNormals, 12);
   drawMesh->setTexCoords(80, VertexUV, 8);

   Note that different indices for vertices, normals and texcoords are allowed,
   hence the various element numbers 100, 120 and 80.


   Example 2 (interleaved input)

   float Vertices[100] = {
                            x0, y0, z0,   u0, v0,   nx0, ny0, nz0,
                            x1, y1, z1,   u1, v1,   nx1, ny1, nz1,
                            ...
                          };

   The stride is 8*4 = 32 bytes.
   We use parameters as follows.

   drawMesh->setVertices(100, Vertices, 32);
   drawMesh->setNormals(100, (char*)Vertices + 20, 32);
   drawMesh->setTexCoords(100, (char*)Vertices + 12, 32);
   
3. Set index data.

   Two methods are supported for this.

   You can either specify one index set for all vertex attributes
   or use another index buffer for each vertex attribute.
   The latter means having different indices for vertex and texcoords for example.


   drawMesh->setNumFaces(32, 96);


   for each face i
     int* faceVertexIndices = {v0, v1, v2, ...};
     setFaceVerts(i, 3, faceVertexIndices);

4. finish the initialization by calling the build() function

*/

namespace ACG{

class ACGDLLEXPORT MeshCompilerFaceInput
{
  // face data input interface
  // allows flexible and memory efficient face data input

public:
  MeshCompilerFaceInput(){}
  virtual ~MeshCompilerFaceInput(){}

  virtual int getNumFaces() const = 0;

  virtual int getNumIndices() const = 0;

  virtual int getFaceSize(const int _faceID) const = 0;

  virtual int getSingleFaceAttr(const int _faceID, const int _faceCorner, const int _attrID) const;

  virtual bool getFaceAttr(const int _faceID, const int _attrID, int* _out) const {return false;}

  virtual int* getFaceAttr(const int _faceID, const int _attrID) const {return 0;}


  // Adjacency information can be provided if it has been generated already.
  // Otherwise it will be generated on the fly when needed, which might be time consuming.

  virtual int getVertexAdjCount(const int _vertexID) const {return -1;}

  virtual int getVertexAdjFace(const int _vertexID, const int _k) const {return -1;}

};

class ACGDLLEXPORT MeshCompilerDefaultFaceInput : public MeshCompilerFaceInput
{
public:
  MeshCompilerDefaultFaceInput(int _numFaces, int _numIndices);
  virtual ~MeshCompilerDefaultFaceInput(){}

  int getNumFaces() const  override {return numFaces_;}
  int getNumIndices() const override {return numIndices_;}

  int getFaceSize(const int _faceID) const override {return faceSize_[_faceID];}

  int getSingleFaceAttr(const int _faceID, const int _faceCorner, const int _attrID) const override;

  bool getFaceAttr(const int _faceID, const int _attrID, int* _out) const override;

  void dbgWriteToObjFile(FILE* _file, int _posAttrID = 0, int _normalAttrID = -1, int _texcAttrID = -1);


  void setFaceData(int _faceID, int _size, int* _data, int _attrID = 0);

protected:

  int numFaces_,
    numIndices_;

  // input data is stored in a sequence stream
  //  face offsets may not be in sequence
  std::vector<int> faceOffset_;
  std::vector<int> faceSize_;

  // face index buffer for each vertex attribute
  std::vector<int> faceData_[16];

};


class ACGDLLEXPORT MeshCompilerVertexCompare
{
public:
  MeshCompilerVertexCompare(double _d_eps = 1e-4, float _f_eps = 1e-4f) : d_eps_(_d_eps), f_eps_(_f_eps) {}

  virtual bool equalVertex(const void* v0, const void* v1, const VertexDeclaration* _decl);

  const double d_eps_;
  const float f_eps_;
};

class ACGDLLEXPORT MeshCompiler
{
public:

  explicit MeshCompiler(const VertexDeclaration& _decl);

  virtual ~MeshCompiler();

//===========================================================================
//===========================================================================  

  void setVertices(size_t _num, const void* _data, size_t _stride = 0, bool _internalCopy = false, GLuint _fmt = 0, int _elementSize = -1);

  void setNormals(size_t _num, const void* _data, size_t _stride = 0, bool _internalCopy = false, GLuint _fmt = 0, int _elementSize = -1);

  void setTexCoords(size_t _num, const void* _data, size_t _stride = 0, bool _internalCopy = false, GLuint _fmt = 0, int _elementSize = -1);

  void setAttribVec(int _attrIdx, size_t _num, const void* _data, size_t _stride = 0, bool _internalCopy = false, GLuint _fmt = 0, int _elementSize = -1);

  void setAttrib(int _attrIdx, int _v, const void* _data);


  int getNumInputAttributes(int _attrIdx) const;

//===========================================================================
//===========================================================================  

  void setFaceInput(MeshCompilerFaceInput* _faceInput);

//===========================================================================
//===========================================================================  

  void setNumFaces(const int _numFaces, const int _numIndices);


  void setIndexBufferInterleaved(int _numTris, int _indexSize, const void* _indices);

  void setFaceVerts(int _i, int _v0, int _v1, int _v2);

  void setFaceVerts(int _i, int _faceSize, int* _v);

  void setFaceNormals(int _i, int _v0, int _v1, int _v2);
  
  void setFaceNormals(int _i, int _faceSize, int* _v);

  void setFaceTexCoords(int _i, int _v0, int _v1, int _v2);

  void setFaceTexCoords(int _i, int _faceSize, int* _v);


  void setFaceAttrib(int _i, int _v0, int _v1, int _v2, int _attrID);

  void setFaceAttrib(int _i, int _faceSize, int* _v, int _attrID);


//===========================================================================
//===========================================================================  


  void setFaceGroup(int _i, short _groupID);

  // subset/group management
  struct Subset
  {
    int id; // subset id
    unsigned int startIndex; // 1st occurrence of group in index buffer
    unsigned int numTris; // number of tris belonging to subset in index buffer

    unsigned int numFaces; // number of faces belonging to subset
    unsigned int startFace; // index into sorted list of faces
  };

  int findGroupSubset(int _groupID);

  int getFaceGroup(int _faceID) const;

  int getTriGroup(int _triID) const;

  int getNumSubsets() const {return (int)subsets_.size();}

  const Subset* getSubset(int _i) const;


//===========================================================================
//===========================================================================  


  void build(bool _weldVertices = false, bool _optimizeVCache = true, bool _needPerFaceAttribute = false, bool _keepIsolatedVertices = false);

  int getNumVertices() const {return numDrawVerts_;}

  void setProvokingVertex(int _v);

  int getProvokingVertex() const {return provokingVertex_;}


  void getVertexBuffer(void* _dst, const int _offset = 0, const int _range = -1);

  const int* getIndexBuffer() const {return indices_.data();}

  void getIndexAdjBuffer(void* _dst, const int _borderIndex = -1);

  void getIndexAdjBuffer_BruteForce(void* _dst, const int _borderIndex = -1);


  int getNumTriangles() const {return numTris_;}

  int getNumFaces() const;

  inline int getFaceSize(const int _i) const
  {
    return int(faceSize_.empty() ? maxFaceSize_ : faceSize_[_i]);
  }

  const VertexDeclaration* getVertexDeclaration() const {return &decl_;}

  void getVertex(int _id, void* _out) const;

  int getIndex(int _i) const;


//===========================================================================
//===========================================================================  


  int mapToOriginalVertexID(const size_t _i, int& _faceID, int& _cornerID) const;

  int mapToOriginalFaceID(const int _triID) const;

  const int* mapToOriginalFaceIDPtr() const;

  int mapToDrawVertexID(const int _faceID, const int _cornerID) const;

  int mapToDrawTriID(const int _faceID, const int _k = 0, int* _numTrisOut = 0) const;


//===========================================================================
//===========================================================================  

  bool isTriangleMesh() const;

  bool isFaceEdge(const int _triID, const int _edge) const;


private:

  // compute adjacency information: vertex -> neighboring faces (, face -> neighboring faces [removed] )
  void computeAdjacency(bool _forceRecompute = false);

  // convert per-face vertices to unique ids
  void splitVertices();

private:

  // small helper functions

  void getInputFaceVertex(const int _face, const int _corner, int* _out) const;

  void getInputFaceVertex_Welded(const int _face, const int _corner, int* _out) const;

  void getInputFaceVertexData(const int _face, const int _corner, void* _out) const;


  inline int getInputIndex( const int& _face, const int& _corner, const int& _attrId ) const
  {
    return faceInput_->getSingleFaceAttr(_face, _corner, _attrId);

    // alternatively avoid virtual function call at cost of higher memory overhead ( could not confirm any run-time difference )
    // to use this, uncomment code in prepareData() that initializes faceData_ array as well
//    return faceData_[(getInputFaceOffset(_face) + _corner) * numAttributes_ + _attrId];
  }


private:

  // ====================================================
  // input data


  // vertex buffer input

  struct ACGDLLEXPORT VertexElementInput 
  {
    VertexElementInput();
    ~VertexElementInput();

    char* internalBuf;

    const char* data;

    int count;

    int stride;

    int attrSize;


    // vertex data access

    GLuint fmt;

    int elementSize;

    void getElementData(int _idx, void* _dst, const VertexElement* _desc) const;
  };
  
  // input vertex data
  VertexElementInput  input_[16];

  // convenient attribute indices
  int inputIDPos_;  // index of positions into input_ array
  int inputIDNorm_; // index of normals into input_ array
  int inputIDTexC_; // index of texcoords into input_ array

  int                 numAttributes_;
  VertexDeclaration   decl_;


  // input face data

  int   numFaces_, 
        numIndices_;

  std::vector<int>           faceStart_;         // start position in buf for each face
  std::vector<int>           faceSize_;          // face size, copy of faceInput_->getFaceSize() for better performance
  std::vector<int>           faceData_;
  size_t                     maxFaceSize_;       // max(faceSize_)
  bool                       constantFaceSize_;
  std::vector<short>         faceGroupIDs_;      // group id for each face (optional input)
  int                        curFaceInputPos_;   // current # indices set by user

  MeshCompilerFaceInput* faceInput_;   // face data input interface
  bool deleteFaceInputeData_;       // delete if face input data internally created

  std::vector<int>  faceBufSplit_; // mapping from (faceID, cornerID) to interleaved vertex id after splitting
  std::vector<int>  faceSortMap_;  // face IDs sorted by group; maps sortFaceID -> FaceID
  int               provokingVertex_; // provoking vertex of each triangle
  bool              provokingVertexSetByUser_; // was the provoking vertex selected by user or set to default?

  int   numTris_;
  std::vector<int>  triIndexBuffer_; // triangulated index buffer with interleaved vertices

  // IDs of isolated vertices: index into input position buffer
  std::vector<int>  isolatedVertices_;

  // face grouping with subsets for per-face materials
  int     numSubsets_;
  std::vector<Subset> subsets_;
  std::map<int, int> subsetIDMap_; // maps groupId -> subsetID

  // =====================================================

  struct ACGDLLEXPORT AdjacencyList 
  {
    AdjacencyList()
      : start(0), count(0), buf(0), bufSize(0), num(0) {}
    ~AdjacencyList()
    {
      delete [] start;
      delete [] buf;
      delete [] count;
    }

    void init(int n);
    int  getAdj(int i, int k) const;
    int  getCount(int i) const;

    void clear();

    int* start;   // index to adjacency buffer
    unsigned char* count;   // # of adjacent faces
    int* buf;     // adjacency data
    int  bufSize; // size of buf
    int  num;     // # adjacency entries

//    void dbgdump(FILE* file) const;
    void dbgdump(std::ofstream& file) const;
  };

  // adjacency list: vertex -> faces
  AdjacencyList adjacencyVert_;

  // adjacency access interface (choosing between user input / self generated data)
  int getAdjVertexFaceCount(int _vertexID) const;
  int getAdjVertexFace(int _vertexID, int _k) const;


  struct WeldListEntry
  {
    int faceId;
    int cornerId;
    
    int refFaceId;
    int refCornerId;
  };

  struct ACGDLLEXPORT WeldList
  {
    void add(const int _face, const int _corner);

    std::vector< WeldListEntry > list;

    MeshCompiler* meshComp;
    MeshCompilerVertexCompare* cmpFunc;

    char* workBuf;
  };


  static MeshCompilerVertexCompare defaultVertexCompare;
  MeshCompilerVertexCompare* vertexCompare_;

  // mapping from <faceId, faceCornerId> -> <weldFaceId, weldFaceCorner>
//  std::vector< std::pair<int, unsigned char> > vertexWeldMap_;   // std::pair<int, unsigned char> gets padded to 8 bytes
  std::vector<int> vertexWeldMapFace_;
  std::vector<int> vertexWeldMapCorner_;


  struct ACGDLLEXPORT VertexSplitter 
  {
    // worst case split: num entries in vertex adj list
    // estBufferIncrease: if numWorstCase == 0, then we estimate an increase in vertex buffer by this percentage
    VertexSplitter(int numAttribs,
                   int numVerts,
                   int numWorstCase = 0,
                   float estBufferIncrease = 0.5f);

    ~VertexSplitter();

    int split(int* vertex);

    bool isIsolated(const int vertexPosID);

    int  numAttribs;

    int  numVerts;

    const int  numBaseVerts;

//    int* splits;
    std::vector<int> splits;

    // split list access
    int  getNext(const int id);
    int* getAttribs(const int id);
    void setNext(const int id, const int next);
    void setAttribs(const int id, int* attr);

    // debugging metrics
    int dbg_numResizes;
    int dbg_numSplits;
  };

  VertexSplitter*  splitter_;

  // =====================================================

  // mappings

  std::vector<int> triToSortFaceMap_;

  std::vector<int> triOptMap_;

//  std::vector<std::pair<int, unsigned char> > vertexMap_; // sizeof( std::pair<int, unsigned char> ) = 8!!
  std::vector<int> vertexMapFace_;
  std::vector<int> vertexMapCorner_;

  std::vector<int> faceToTriMap_;
  std::vector<int> faceToTriMapOffset_; 

  std::vector<int> triToFaceMap_;

  // =====================================================

  // final buffers used for drawing

  size_t numDrawVerts_;

  size_t numIsolatedVerts_;

  std::vector<int>  indices_;

private:

  // return interleaved vertex id for input buffers
  int getInputIndexSplit(const int _face, const int _corner) const;

  void setInputIndexSplit(const int _face, const int _corner, const int _val);

  int mapTriToInputFace(const int _tri) const;

  int getInputIndexOffset(const int _face, const int _corner) const;

  inline int getInputFaceOffset(const int _face) const
  {
    return int(faceStart_.empty() ? maxFaceSize_ * _face : faceStart_[_face]);
  }

  void prepareData();

  // find isolated vertices
  void findIsolatedVertices();

  // make sure each face has one vertex id without any references by neighboring faces
  // split vertices when necessary
  void forceUnsharedFaceVertex();

  // eliminate duplicate attribute entries
  void weldVertices();

  // fix incomplete welding map if mesh contains isolated vertices
  void fixWeldMap();

  // convert n-poly -> tris (triangle fans)
  void triangulate();

  // resolve triangulation
  void resolveTriangulation();

  // sort input faces by group ids
  void sortFacesByGroup();

  // v-cache optimization + vertex reorder
  void optimize();

  // create vertex mapping: input id <-> final buffer id
  void createVertexMap(bool _keepIsolatedVerts);

  // create face mapping: input id <-> final tri id
  void createFaceMap();

public:

  void getIndexAdjBuffer_MT(void* _dst, const int _borderIndex = -1);

  // debugging tools

  void dbgdump(const char* _filename) const;

  void dbgdumpObj(const char* _filename) const;

  void dbgdumpInputBin(const char* _filename, bool _seperateFiles = false) const;

  void dbgdumpInputObj(const char* _filename) const;

  void dbgdumpAdjList(const char* _filename) const;

  bool dbgVerify(const char* _filename) const;

  std::string vertexToString(const void* v) const;

  size_t getMemoryUsage(bool _printConsole = true) const;

  std::string checkInputData() const;
};

struct RingTriangle
{
  RingTriangle() {}
  RingTriangle(int i, RingTriangle* p, RingTriangle* n) : id(i), prev(p), next(n) {}

  int id; // local index of the triangle within a polygon [0, ... faceSize-3]
  RingTriangle* prev; // prev triangle in the ring
  RingTriangle* next; // next triangle in the ring
};


}