怎么定义一个QuadTriMesh, 同时支持quad and triangle faces?

class QuadTriMesh : public BaseMesh {

public:

struct Face;

...

};

#define NIL uint(~0)

struct QuadTriMesh::Face {

unsigned int id;

unsigned int v[4];

bool isQuadFace() const { return v[3] != NIL; };

};