source: GTP/trunk/Lib/Vis/Preprocessing/src/RayCaster.cpp @ 1900

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


namespace GtpVisibilityPreprocessor {


#define DEBUG_RAYCAST 0

#define EXACT_BOX_CLIPPING 1

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
#if EXACT_BOX_CLIPPING
        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 {
          //            cout<<" invalid hp "<<tmin<<" "<<tmax<<endl;
          //            cout<<" box "<<box<<endl;
          //            cout<<" origin "<<origin<<endl;
          //            cout<<" direction "<<direction<<endl;
          //            cout<< "inv dir"<<ray.GetInvDir()<<endl;
          return false;
        }
#else
        hit.mPoint = origin + direction*Magnitude(box.Diagonal());
#endif
  }
  else
        if (mPreprocessor.mDetectEmptyViewSpace) {
          if (DotProd(hit.mNormal, direction) >= -Limits::Small) {      
                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<<"PRA"<<flush;
#endif

        // regardless of the pruneInvalidRays setting reject rays whic degenerate to a point
        //      if (EpsilonEqualV3(hitA.mPoint, hitB.mPoint, Limits::Small))
        //        return 0;
        
        if (pruneInvalidRays) {
          if (!hitA.mObject && !hitB.mObject) {
                return 0;
          }
        }
        
        const bool validA = 
          ValidateRay(simpleRay.mOrigin, simpleRay.mDirection, box, hitA);
        
        const bool validB = castDoubleRay && 
          ValidateRay(simpleRay.mOrigin, -simpleRay.mDirection, box, hitB);
        
#if DEBUG_RAYCAST
        Debug<<"PR1"<<flush;
#endif
        
        // reset both contributions
        if (!validA || !validB) {
          if (pruneInvalidRays)
                return 0;
          // reset both contributions of this ray
          hitA.mObject = NULL;
          hitB.mObject = NULL;
        }
          
        
        const bool validSample = true;
        // 8.11. 2007 JB
        // degenerate rays checked by geometrical constraint...
        //      !pruneInvalidRays || (hitA.mObject != hitB.mObject);
        
#if DEBUG_RAYCAST
        Debug<<"PR2"<<flush;
#endif

        if (validSample) {
          if (!pruneInvalidRays || hitA.mObject) {
                VssRay *vssRay = new VssRay(
                                                                        hitB.mPoint,
                                                                        hitA.mPoint,
                                                                        hitB.mObject,
                                                                        hitA.mObject,
                                                                        mPreprocessor.mPass,
                                                                        simpleRay.mPdf
                                                                        );
                
                if (validA)
                  vssRay->mFlags |= VssRay::Valid;
                vssRay->mDistribution = simpleRay.mDistribution;
                vssRays.push_back(vssRay);
                ++ hits;
                //cout << "vssray 1: " << *vssRay << " " << vssRay->mTermination - vssRay->mOrigin << endl;
          }
          
#if DEBUG_RAYCAST
          Debug<<"PR3"<<flush;
#endif

          if (castDoubleRay && (!pruneInvalidRays || hitB.mObject))
                {
                  VssRay *vssRay = new VssRay(
                                                                          hitA.mPoint,
                                                                          hitB.mPoint,
                                                                          hitA.mObject,
                                                                          hitB.mObject,
                                                                          mPreprocessor.mPass,
                                                                          simpleRay.mPdf
                                                                          );
                  if (validB)
                        vssRay->mFlags |= VssRay::Valid;
                  
                  vssRay->mDistribution = simpleRay.mDistribution;
                  vssRays.push_back(vssRay);
                  ++ hits;
                  //cout << "vssray 2: " << *vssRay << endl;
                }
        }
        
#if DEBUG_RAYCAST
        Debug<<"PR4"<<flush;
#endif

        return hits;
}

}