class vertex{
public:
	float x,y,z;
};

struct vertex {
// avoid constructor
 vertex & xyz( float _x = 0.0f, float _y = 0.0f, float _z = 0.0f )  { x = _x; y = _y; z = _z; return *this; }

// math
  vertex & operator += ( const vertex & t ) { x += t.x; y += t.y; z += t.z; return *this; }  
  vertex & operator -= ( const vertex & t ) { x -= t.x; y -= t.y; z -= t.z; return *this; }  

  vertex & operator *= ( float t ) { x *= t; y *= t; z *= t; return *this; }  
  vertex & operator /= ( float t ) { x /= t; y /= t; z /= t; return *this; }  

// length & normalize
  float lenSq ( void ) const { return x * x + y * y + z * z; }
  float length ( void ) const { return sqrtf(lenSq); }

  vertex & normalize( void ) { return *this /= length(); }

// friend operators
  friend vertex operator + ( const vertex & a , const vertex & b ) { vertex t; return t.xyz(a.x + b.x, a.y + b.y, a.z + b.z); }
  friend vertex operator - ( const vertex & a , const vertex & b ) { vertex t; return t.xyz(a.x - b.x, a.y - b.y, a.z - b.z); }

  friend vertex operator * ( const vertex & a, float t ) { vertex v = a; return v *= t; }  
  friend vertex operator / ( const vertex & a, float t ) { vertex v = a; return v /= t; }  

// scalar product (overloaded *)
  friend float operator * ( const vertex & a , const vertex & b ) { return a.x * b.x + a.y * b.y + a.z * b.z; }
  
// vector product (overloaded |)
  friend vertex operator | ( const vertex & a , const vertex & b ) 
  { 
    vertex t; 
    return t.xyz(a.y * b.z - a.z * b.y, 
                     a.x * b.z - a.z * b.x,  
                     a.x * b.y - a.y * b.x);
  }
};

void QGLMesh::CalcNormal(const & vertex p1, const & vertex p2, const & vertex p3, vertex *res)
{
 *res = ((p2 - p1) | (p3 - p1)).normalize();
}
{

QHash<int,A*> values_;