ShadowExplorer.h

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/* $Id: HiddenPointExplorer.h,v 1.2 2002/11/05 14:31:15 anonymous Exp $ */

#ifndef __SHADOW_EXPLORER_H
#define __SHADOW_EXPLORER_H

#include <esg/Definitions.h>
#include <esg/explorer/RayIntExplorer.h>
#include <esg/LightArray.h>

/*
 * The result() method returns true if and only if the point of interest
 * (ray origin) is shadowed by some object in given direction (ray direction),
 * i.e. if there exists a point of intersection
 * of given ray with some object in scene and if this intersection
 * is closer than maximal distance (parametter m in constructor)
 */

namespace esg {

class OGSCENE_EXPORT ShadowExplorer : public RayIntExplorer {
protected:
    PointEnv                  _env;       // aux. variable
    Geometry                * _pGeometry; // aux. variable
    SceneGraphObject::OID     _lightOID;  // OID of light source itself
    LightArray::BlockingObj   _blockingObj;

protected:
    // Functionality of _iterate(), _process_leaf() and
    // _accept_new_transformation() methods is moved directly into
    // the redefined _explore() function to get the tests a little bit faster
    virtual bool _explore                   (SceneGraphObject&);
    virtual bool _iterate                   (SceneGraphObject&) {return false;}
    virtual bool _process_leaf              (SceneGraphObject&) {return false;}
    virtual void _accept_new_transformation (const Matrix4&)    {}

public:
    ShadowExplorer(const Vector3&        o,  // ray's origin
                   const Vector3&        d,  // direction to light source
                   SceneGraphObject::OID oid,
                   float                 m = MAXFLOAT) // light source distance
        : RayIntExplorer(o, d, NULL, m), _lightOID(oid) {}

    virtual void explore (SceneGraphObject&);

    bool result () { return (_blockingObj.pObj != NULL); }

    const LightArray::BlockingObj& getBlockingObj (void) const { return _blockingObj; }

    virtual void reinit (const Vector3&        o,
                         const Vector3&        d,
                         SceneGraphObject::OID oid,
                         Intersector*          pI = NULL,
                         float                 m = MAXFLOAT)
    {
        _transformed = false;
        _origin.set(o);
        _direction.set(d);
        _trOrigin.set(o);
        _trDirection.set(d);
        _maxDist = m;
        _blockingObj.pObj = NULL;
        _blockingObj.transformed = false;
        _lightOID = oid;
    }

    virtual void reinit (const Vector3&        o,
                         const Vector3&        d,
                         SceneGraphObject::OID oid,
                         float                 m = MAXFLOAT)
    {
        _transformed = false;
        _origin.set(o);
        _direction.set(d);
        _trOrigin.set(o);
        _trDirection.set(d);
        _maxDist = m;
        _blockingObj.pObj = NULL;
        _blockingObj.transformed = false;
        _lightOID = oid;
    }
};

}; // namespace

#endif // __SHADOW_POINT_EXPLORER_H

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