#ifndef GEOMETRY

 #define GEOMETRY

 #include <QPolygonF>

 QRectF addBBox(QRectF r1, QRectF r2);

 bool isInBox(const QPointF &p, const QRectF &box);

 class ConvexPolygon:public QPolygonF

 {

 public:

 	ConvexPolygon ();

 	ConvexPolygon (QPolygonF p);

 	void calcCentroid() ;

 	QPointF centroid() const;

 	qreal weight() const;

 private:

 	QPointF _centroid;

 	qreal _area;

 };

 QPointF normalize (const QPointF &p);

 qreal dotProduct (const QPointF &a, const QPointF &b);

 QPointF scale  (const QPointF &v,const qreal &f);

 QPointF invert (const QPointF &v);

 class PolygonCollisionResult {

 public:

     // Are the polygons going to intersect forward in time?

     bool willIntersect;

     // Are the polygons currently intersecting?

     bool intersect;

     // The translation to apply to the first polygon to push the polygons apart.

     QPointF minTranslation;

 };

 void projectPolygon(QPointF axis, QPolygonF polygon, qreal &min, qreal &max) ;

 qreal intervalDistance(qreal minA, qreal maxA, qreal minB, qreal maxB);

 PolygonCollisionResult polygonCollision(QPolygonF polygonA, 

                               QPolygonF polygonB, QPointF velocity);

 #endif