source: branches/VUT/0.3/GtpVisibility/include/DistanceQueue.h @ 87

#ifndef _DistanceQueue_H__
#define _DistanceQueue_H__

#include "OcclusionQuery.h"

#include <queue>

namespace GtpVisibility {

/*  We define HierarchyNode as void * because
        there is no common ancestor for hierarchy nodes in Ogre
*/
typedef void HierarchyNode;

class HierarchyInterface;
/** This class implements the less operator for the priority queue, i.e.,
        a greater distance has a lower priority in the queue.
*/
template <typename T> class GreaterDistance
{
public:
        GreaterDistance(HierarchyInterface *hierarchyInterface): mHierarchyInterface(hierarchyInterface)
        {}
        
        bool operator() (T v1, T v2) const
        {
                return mHierarchyInterface->GetSquaredDistance(v1) > mHierarchyInterface->GetSquaredDistance(v2);
        }
                
private:
        HierarchyInterface *mHierarchyInterface;
};

/** A priority queue where closer hierarchy nodes are given a higher priority.
*/
typedef std::priority_queue<HierarchyNode *, std::vector<HierarchyNode *>, GreaterDistance<std::vector<HierarchyNode *>::value_type> > DistanceQueue;

} // namespace GtpVisibility

#endif // DistanceQueue_H