source: GTP/trunk/Lib/Vis/Preprocessing/src/RayCaster.cpp @ 1551

#include "RayCaster.h"
#include "VssRay.h"
#include "Ray.h"
#include "Preprocessor.h"


namespace GtpVisibilityPreprocessor {


#define DEBUG_RAYCAST 0


RayCaster::RayCaster(const Preprocessor &preprocessor):
mPreprocessor(preprocessor)
{
}


RayCaster::~RayCaster()
{
}


VssRay *RayCaster::CastRay(const SimpleRay &simpleRay,
                                                   const AxisAlignedBox3 &box,
                                                   const bool castDoubleRay)
{
        VssRayContainer rays;
        CastRay(simpleRay, rays, box, castDoubleRay);

        if (!rays.empty())
                return rays.back();
        else
                return NULL;
}


/** Checks if ray is valid, (e.g., not in empty view space or outside the view space)
*/
bool RayCaster::ValidateRay(const Vector3 &origin,
                                                        const Vector3 &direction,
                                                        const AxisAlignedBox3 &box,
                                                        Intersection &hit)
{
        if (!hit.mObject) 
        {
                // compute intersection with the scene bounding box
                static Ray ray;
                mPreprocessor.SetupRay(ray, origin, direction);

                float tmin, tmax;
                if (box.ComputeMinMaxT(ray, &tmin, &tmax) && (tmin < tmax))
                {
                        hit.mPoint = ray.Extrap(tmax);
                }
                else
                {
                        return false;
                }               
        } 
        else if (mPreprocessor.mDetectEmptyViewSpace)
        {
                if (DotProd(hit.mNormal, direction) >= 0) 
                {       
                        hit.mObject = NULL;
                        return false;
                }
        }

        return true;
}


int RayCaster::ProcessRay(const SimpleRay &simpleRay,
                                                  Intersection &hitA,
                                                  Intersection &hitB,
                                                  VssRayContainer &vssRays,
                                                  const AxisAlignedBox3 &box,
                                                  const bool castDoubleRay,
                                                  const bool pruneInvalidRays)
{
        int hits = 0;

#if DEBUG_RAYCAST
        Debug<<"PR ";
#endif
        
        if (pruneInvalidRays)
        {
                if (!hitA.mObject && !hitB.mObject)
                {
                        return 0;
                }
        
                // inside test for bounding box
                // enlarge box slightly so the view point fits for sure
                AxisAlignedBox3 sbox = box;
                sbox.Enlarge(Vector3(-Limits::Small));

                if (!sbox.IsInside(simpleRay.mOrigin))
                {
                        return 0;
                }
        }

        const bool validA = 
                ValidateRay(simpleRay.mOrigin, simpleRay.mDirection, box, hitA);
        if (!validA && pruneInvalidRays)
        {
                return 0;
        }

        const bool validB = castDoubleRay && 
                ValidateRay(simpleRay.mOrigin, -simpleRay.mDirection, box, hitB);

        if (!validB && pruneInvalidRays)
        {
                return 0;
        }

        const bool validSample = !pruneInvalidRays || (hitA.mObject != hitB.mObject);
        
        if (validSample) 
        {
                if (!pruneInvalidRays || hitA.mObject) 
                {
                        VssRay *vssRay = new VssRay(
                                hitB.mPoint,
                                hitA.mPoint,
                                hitB.mObject,
                                hitA.mObject,
                                mPreprocessor.mPass,
                                simpleRay.mPdf
                                );
                        
                        vssRays.push_back(vssRay);
                        ++ hits;
                        //cout << "vssray 1: " << *vssRay << " " << vssRay->mTermination - vssRay->mOrigin << endl;
                }

                if (castDoubleRay && (!pruneInvalidRays || hitB.mObject))
                {
                        VssRay *vssRay = new VssRay(
                                hitA.mPoint,
                                hitB.mPoint,
                                hitA.mObject,
                                hitB.mObject,
                                mPreprocessor.mPass,
                                simpleRay.mPdf
                                );
                        
                        vssRays.push_back(vssRay);
                        ++ hits;
                        //cout << "vssray 2: " << *vssRay << endl;
                }
        }

        return hits;
}

}