OpenCasCade数学库 - 包围盒（Bnd_Box）的变换(Transformed)

﹏ヽ暗。殇╰゛Y 2021-12-09 06:09 479阅读 0赞

1.包围盒（Bnd\_Box）的定义

class Bnd_Box
    {
    public:
        ...
    private:
      Standard_Real Xmin;
      Standard_Real Xmax;
      Standard_Real Ymin;
      Standard_Real Ymax;
      Standard_Real Zmin;
      Standard_Real Zmax;
      Standard_Real Gap;
      Standard_Integer Flags;
    };

2.变换(gp\_Trsf)的定义

class gp_Trsf
    {
    public:
        ...
    private:
      Standard_Real scale;
      gp_TrsfForm shape;     //几何变换类型
      gp_Mat matrix;
      gp_XYZ loc;
    };

3.包围盒的变换(Transformed)

Bnd_Box Bnd_Box::Transformed (const gp_Trsf& T) const
    {
      gp_TrsfForm F = T.Form();
      Bnd_Box newb(*this);
      if ( IsVoid() ) return newb;
    
      if      (F == gp_Identity) {}               //没有变化
      else if (F == gp_Translation) {             //平移
        Standard_Real DX,DY,DZ;
        (T.TranslationPart()).Coord(DX,DY,DZ);
        if (!IsOpenXmin()) newb.Xmin += DX;
        if (!IsOpenXmax()) newb.Xmax += DX;
        if (!IsOpenYmin()) newb.Ymin += DY;
        if (!IsOpenYmax()) newb.Ymax += DY;
        if (!IsOpenZmin()) newb.Zmin += DZ;
        if (!IsOpenZmax()) newb.Zmax += DZ;
      }
      else {
        gp_Pnt P[8];
        Standard_Boolean Vertex[8];
        Standard_Integer i;
        for (i=0;i<8;i++) Vertex[i] = Standard_True;
        gp_Dir D[6];
    //    Standard_Integer vertices = 0;
        Standard_Integer directions = 0;
    
        if (IsOpenXmin())
        {
          directions++;
          D[directions-1].SetCoord(-1., 0., 0.);
          Vertex[0] = Vertex[2] = Vertex[4] = Vertex[6] = Standard_False;
        }
        if (IsOpenXmax())
        {
          directions++;
          D[directions-1].SetCoord( 1., 0., 0.);
          Vertex[1] = Vertex[3] = Vertex[5] = Vertex[7] = Standard_False;
        }
        if (IsOpenYmin())
        {
          directions++;
          D[directions-1].SetCoord( 0.,-1., 0.);
          Vertex[0] = Vertex[1] = Vertex[4] = Vertex[5] = Standard_False;
        }
        if (IsOpenYmax())
        {
          directions++;
          D[directions-1].SetCoord( 0., 1., 0.);
          Vertex[2] = Vertex[3] = Vertex[6] = Vertex[7] = Standard_False;
        }
        if (IsOpenZmin())
        {
          directions++;
          D[directions-1].SetCoord( 0., 0.,-1.);
          Vertex[0] = Vertex[1] = Vertex[2] = Vertex[3] = Standard_False;
        }
        if (IsOpenZmax())
        {
          directions++;
          D[directions-1].SetCoord( 0., 0., 1.);
          Vertex[4] = Vertex[5] = Vertex[6] = Vertex[7] = Standard_False;
        }
    
        newb.SetVoid();
        for (i=0;i<directions;i++) {    //只对开放区间的方向做转换
          D[i].Transform(T);
          newb.Add(D[i]);
        }
        P[0].SetCoord(Xmin,Ymin,Zmin);
        P[1].SetCoord(Xmax,Ymin,Zmin);
        P[2].SetCoord(Xmin,Ymax,Zmin);
        P[3].SetCoord(Xmax,Ymax,Zmin);
        P[4].SetCoord(Xmin,Ymin,Zmax);
        P[5].SetCoord(Xmax,Ymin,Zmax);
        P[6].SetCoord(Xmin,Ymax,Zmax);
        P[7].SetCoord(Xmax,Ymax,Zmax);
        for (i=0;i<8;i++) {
          if (Vertex[i]) {       //只对封闭区间的点做转换
    	    P[i].Transform(T);
    	    newb.Add(P[i]);
          }
        }
        newb.Gap=Gap;
      }
      return newb;
    }