QEM三维模型抽稀算法C++Wraper实例

去年研究了QEM算法，下面简要记录下研究过程

一，QEM三维模型简化算法，介绍见

1.QEM(Quadric Error Mactrics，二次误差测度)模型简化算法，具有兼顾执行效率和模型质量的优点（https://www.cnblogs.com/kekec/archive/2011/12/07/2279320.html）

2.C++源码：http://mgarland.org/software/qslim.html

二，Wraper代码实现

 新建CLR C++项目“QSlimWraper”，包含Mesh.h，QSlim.h，QSlim.cpp代码

 新建Wraper.cpp，实现qslim_init()，qslim_run()函数，见下面

#include "Mesh.h"
#include "QSlim.h"  
 

using namespace System::Runtime::InteropServices;
static void qslim_init()
{
    int i;
    cerr << "Reading input ..." << endl;
    cerr << "Cleaning up initial input ..." << endl;
    int initialVertCount = M0.vertCount();
    int initialEdgeCount = M0.edgeCount();
    int initialFaceCount = M0.faceCount();
    for (i = 0; i < M0.faceCount(); i++)
        if (!M0.face(i)->plane().isValid())
            M0.killFace(M0.face(i));
    M0.removeDegeneracy(M0.allFaces());
    for (i = 0; i < M0.vertCount(); i++)
    {
        if (M0.vertex(i)->edgeUses().length() == 0)
            M0.vertex(i)->kill();
    }
    cerr << "Input model summary:" << endl;
    cerr << "    Vertices    : " << initialVertCount << endl;
    cerr << "    Edges       : " << initialEdgeCount << endl;
    int man = 0, non = 0, bndry = 0, bogus = 0;
    for (i = 0; i < M0.edgeCount(); i++)
        switch (M0.edge(i)->faceUses().length())
        {
        case 0:
            bogus++;
            break;
        case 1:
            bndry++;
            break;
        case 2:
            man++;
            break;
        default:
            non++;
            break;
        }
    if (bogus)
        cerr << "        Bogus       : " << bogus << endl;
    cerr << "        Boundary    : " << bndry << endl;
    cerr << "        Manifold    : " << man << endl;
    cerr << "        Nonmanifold : " << non << endl;

    cerr << "    Faces       : " << initialFaceCount << endl;
}

static void qslim_run()
{
    decimate_init(M0, pair_selection_tolerance); 
    while (M0.validFaceCount > face_target&& decimate_min_error() < error_tolerance)
    {
        decimate_contract(M0); 
    }
} 

新建QSlimWraper namespace，实现CLR，见下面

namespace QSlimWraper
{
    public ref struct Point3dWrap
    {
        float X;
        float Y;
        float Z;
        int R;//red
        int G;//green
        int B;//blue
        Point3dWrap()
        {
            X = 0;
            Y = 0;
            Z = 0;
        }
        ~Point3dWrap()
        {
        }
        Point3dWrap(float x, float y, float z)
        {
            this->X = x;
            this->Y = y;
            this->Z = z;
        }
        Point3dWrap(float x, float y, float z, int r, int g, int b)
        {
            this->X = x;
            this->Y = y;
            this->Z = z;
            this->R = r;
            this->G = g;
            this->B = b;
        }
    };

    public ref struct TriangleWrap
    {
        int pIndex0;
        int pIndex1;
        int pIndex2;
        int R;//red
        int G;//green
        int B;//blue

        TriangleWrap()
        {
            this->pIndex0 = -1;
            this->pIndex1 = -1;
            this->pIndex2 = -1;
        }
        ~TriangleWrap()
        {
        }
        TriangleWrap(int p0index, int p1index, int p2index)
        {
            this->pIndex0 = p0index;
            this->pIndex1 = p1index;
            this->pIndex2 = p2index;
        }
        TriangleWrap(int p0index, int p1index, int p2index, int r, int g, int b)
        {
            this->pIndex0 = p0index;
            this->pIndex1 = p1index;
            this->pIndex2 = p2index;
            this->R = r;
            this->G = g;
            this->B = b;
        }
    };

    public ref class QSlimWrap
    {
    public:
        QSlimWrap();
        ~QSlimWrap();
        int ReadFile(char* file);
        int OutputFile(char* newFile);

        int InportData(cli::array<Point3dWrap^>^ vertices, cli::array<TriangleWrap^>^ faces, int fTarget);
        int OutputData([Out] cli::array<Point3dWrap^>^% vertices, [Out] cli::array<TriangleWrap^>^% faces);

        int TestParam1(cli::array<Point3dWrap^>^ datas);
        bool Uninitialize();
         

    private:
        Mesh *mesh;
        int faceTarget;
        void InitM0();
        void ReplaceM();
        int Run();
    };

    QSlimWrap::QSlimWrap()
    {
        mesh = new Mesh;
    }

    QSlimWrap::~QSlimWrap()
    {
        Uninitialize();
    }

    bool QSlimWrap::Uninitialize()
    { 
        DisposeQS();
        if (mesh)
        {
            delete mesh;
            mesh = NULL;
        }
        else
            return false;
        return true;
    }

    int QSlimWrap::TestParam1(cli::array<Point3dWrap^>^ datas)
    {
        return 12;
    }

    int QSlimWrap::ReadFile(char* file)
    {
        Mesh m;
        PlyManager::ReadFile(m, file);//result_decix
        mesh->Vertices = m.Vertices;
        mesh->Faces = m.Faces;
        faceTarget = 2 * m.Faces.size() / 3;
        Run();
        return 1;
    }

    int QSlimWrap::OutputFile(char* newFile)
    {
        Mesh m;
        m.Vertices = mesh->Vertices;
        m.Faces = mesh->Faces;
        PlyManager::Output(m, newFile);
        cerr << "Output File:" << newFile << endl;
        return 0;
    }

    void QSlimWrap::InitM0()
    { 
        for (size_t i = 0;i < mesh->Vertices.size();i++)
        {
            Point3d p = mesh->Vertices[i];
            Vec3 v(p.X, p.Y, p.Z);
            //M0.in_Vertex(v);
            M0.in_VertexEx(v, p.R, p.G, p.B);
        }
        for (size_t i = 0;i < mesh->Faces.size();i++)
        {
            Triangle t = mesh->Faces[i];
            //M0.in_Face(t.P0Index,t.P1Index,t.P2Index);
            M0.in_FaceEx(t.P0Index, t.P1Index, t.P2Index, t.R, t.G, t.B);
        } 
    }

    void QSlimWrap::ReplaceM()
    { 
        mesh->Vertices.swap(std::vector<Point3d>());
        mesh->Faces.swap(std::vector<Triangle>());
        mesh->Vertices.reserve(M0.vertCount());
        mesh->Faces.reserve(M0.faceCount());
        int* map = new int[M0.vertCount()];
        for (int i = 0;i < M0.vertCount();i++)
            map[i] = -1;
        int number = 0, number1 = 0;
        for (int i = 0;i < M0.vertCount();i++)
        { 
            if (M0.vertex(i)->isValid())
            { 
                real* data = M0.vertex(i)->raw();
                //Point3d p((float)data[0], (float)data[1], (float)data[2]);
                Point3d p((float)data[0], (float)data[1], (float)data[2], M0.vertex(i)->R, M0.vertex(i)->G, M0.vertex(i)->B);
                map[i] = mesh->AddVertex(p);
                number++;
            }
            else 
                number1++;
        }
         cerr << "ReplaceM M0 Vertices valid  number: " << number << "  not valid  number : " << number1 << "  total Count:" << M0.vertCount()<< endl;
         number=0, number1=0;
        for (int i = 0;i < M0.faceCount();i++)
        {
            if (M0.face(i)->isValid())
            {
                Vertex* v0 = M0.face(i)->vertex(0);
                Vertex* v1 = M0.face(i)->vertex(1);
                Vertex* v2 = M0.face(i)->vertex(2);
                //Triangle t(map[v0->uniqID], map[v1->uniqID], map[v2->uniqID]); 
                Triangle t(map[v0->uniqID], map[v1->uniqID], map[v2->uniqID], M0.face(i)->R, M0.face(i)->G, M0.face(i)->B);
                mesh->AddFace(t);
                number++;
            }
            else
                number1++;
        } 
        cerr << "ReplaceM M0 faces valid  number: " << number << "  not valid  number : " << number1 << "  total Count:" << M0.faceCount() << endl;
        delete[] map;
    }

    int QSlimWrap::Run()
    {
        InitM0();
        //cerr << "InportData runing    fTarget =" << face_target << endl;
        //qslim_init();
        face_target = faceTarget;//2 * m.Faces.size() / 3;
        error_tolerance = HUGE;
        will_use_plane_constraint = true;
        will_use_vertex_constraint = false;
        will_preserve_boundaries = true;
        will_preserve_mesh_quality = true;
        will_constrain_boundaries = true;
        boundary_constraint_weight = 1.0;
        will_weight_by_area = false;
        placement_policy = 1;
        pair_selection_tolerance = 0.0;
        qslim_run();
        ReplaceM();
        return 1;
    }

    int QSlimWrap::InportData(cli::array<Point3dWrap^>^ vertices, cli::array<TriangleWrap^>^ faces, int fTarget)
    { 
        int vCount = vertices->LongLength;
        int fCount = faces->LongLength;
        faceTarget = fTarget;
        float v1 = 0, v2 = 0, v3 = 0;
        int r = 0, g = 0, b = 0;
        long i1 = 0, i2 = 0, i3 = 0;

        for (long i = 0;i < vCount;i++)
        {
            Point3dWrap^ ver = (Point3dWrap^)vertices[i];
            Point3d p3d(ver->X, ver->Y, ver->Z, ver->R, ver->G, ver->B);
            mesh->AddVertex(p3d); 
        }
        delete[] vertices;

        for (long j = 0;j < fCount;j++)
        {
            TriangleWrap^ tg = faces[j];
            Triangle t(tg->pIndex0, tg->pIndex1, tg->pIndex2, tg->R, tg->G, tg->B);
            mesh->AddFace(t); 
        }
        delete[] faces;
        cerr << "InportData run before Vertices Count:" << mesh->Vertices.size() << "  face_target:" << faceTarget << endl;
        Run();
        cerr << "InportData run completed Vertices Count:" << mesh->Vertices.size() << "  faces Count: "<< mesh->Faces.size() <<endl; 
        return 1;
    }
     

    int QSlimWrap::OutputData([Out] cli::array<Point3dWrap^>^% vertices, [Out]  cli::array<TriangleWrap^>^% faces)
    { 
        int vCount = mesh->Vertices.size(); 
        vertices = gcnew cli::array<Point3dWrap^>(vCount);
        for (int i = 0;i < vCount;i++)
        {
            Point3d v = mesh->Vertices[i];
            Point3dWrap^ ver = gcnew Point3dWrap();
            ver->X = v.X, ver->Y = v.Y, ver->Z = v.Z, ver->R = v.R, ver->G = v.G, ver->B = v.B;
            vertices[i] = ver;
        }
        mesh->Vertices.clear();

        int fCount = mesh->Faces.size();
        faces = gcnew cli::array<TriangleWrap^>(fCount);
        for (int i = 0;i < fCount;i++)
        {
            Triangle t = mesh->Faces[i]; 
            TriangleWrap^ tw = gcnew TriangleWrap(t.P0Index, t.P1Index, t.P2Index, t.R, t.G, t.B);
            faces[i] = tw;
        }
        
        mesh->Faces.clear();
        cerr << "OutputData vertices Count:" << vCount << "  faces Count:" << fCount << endl;
        return 1;
    } 
}

三，Wraper验证

     新建C# 项目，引用QSlimWraper.dll,验证代码如下：

   

static void Main(string[] args)
        {

            QSlimWraper wrap = new QSlimWraper();
            unsafe
            {
                //Point3d[] test = new Point3d[10];
                //for (int i = 0; i < 10; i++)
                //{
                //    test[i].X = i + 1;
                //}

                string str = "E:\resultXXX2.ply";
                IntPtr intPtrStr = (IntPtr)Marshal.StringToHGlobalAnsi(str);
                sbyte* sbyteStr = (sbyte*)intPtrStr;
                int res = wrap.ReadFile(sbyteStr);

                str = "E:\resultXXX2XXX.ply";
                intPtrStr = (IntPtr)Marshal.StringToHGlobalAnsi(str);
                sbyteStr = (sbyte*)intPtrStr;
                int res1 = wrap.OutputFile(sbyteStr);

                //Point3dWrap[] pts = new Point3dWrap[100];
                //for (int i = 0; i < 100; i++)
                //{
                //    Point3dWrap aa = new Point3dWrap();
                //    aa.X = i + 1;
                //    pts[i] = aa;
                //}
                //TriangleWrap[] ts = new TriangleWrap[300];
                //for (int i = 0; i < 100; i++)
                //{
                //    TriangleWrap aa = new TriangleWrap();
                //    aa.pIndex0 = i;
                //    aa.pIndex1 = i + 100;
                //    aa.pIndex2 = i + 200;
                //    ts[i] = aa;
                //}
                ////int iii = wrap.TestParam1(test);
                //int face_target = 2 * ts.Length / 3;
                //wrap.InportData(pts, ts, face_target);
                //Point3dWrap[] point3Ds;
                //TriangleWrap[] triangles;
                //wrap.OutputData(out point3Ds, out triangles);
                wrap.Dispose();
            }
        }

四，示例效果，19800 surfaces to 1000 surfaces

 如需要原码可联系