source: trunk/VUT/GtpVisibilityPreprocessor/src/Ray.cpp @ 362

#include "Ray.h"
#include "Plane3.h"

// =========================================================
// Ray .. static item used for generation of unique ID for
// each instantiated ray

// it has to start from 1, since 0 is default and for the first
// ray initial value 0 will not work .. V.H.
// The value 0 is reserved for particular purpose - the rays
// that are converted to canonical space and thus the mailbox
// rayID identification does not work for them!
int
Ray::genID = 1;

// Precompute some Ray parameters. Most of them is used for
// ropes traversal.

void
Ray::Init()
{
  //  if (mType == LOCAL_RAY)
  //    intersections.reserve(1);
  //  else
  //    intersections.reserve(10);
  
  // apply the standard precomputation
  Precompute();
}

void
Ray::Precompute()
{
  // initialize inverted dir
  invDir.SetValue(0.0);
  
  SetId();
}

void
Ray::SetLoc(const Vector3 &l)
{
  loc = l;
}

// make such operation to slightly change the ray direction
// in case any component of ray direction is zero.
void
Ray::CorrectZeroComponents()
{
  const float eps = 1e-6;

  // it does change the ray direction very slightly,
  // but the size direction vector is not practically changed
  
  if (fabs(dir.x) < eps) {
    if (dir.x < 0.0)
      dir.x = -eps;
    else
      dir.x = eps;
  }
  
  if (fabs(dir.y) < eps) {
    if (dir.y < 0.0)
      dir.y = -eps;
    else
      dir.y = eps;
  }
  
  if (fabs(dir.z) < eps) {
    if (dir.z < 0.0)
      dir.z = -eps;
    else
      dir.z = eps;
  }
}


void
Ray::ComputeInvertedDir() const
{
  if ( (invDir.x != 0.0) ||
       (invDir.y != 0.0) ||
       (invDir.z != 0.0) )
    return; // has been already precomputed

  const float eps = 1e-6;
  const float invEps = 1e6;
  
  // it does change the ray direction very slightly,
  // but the size direction vector is not practically changed
  
  if (fabs(dir.x) < eps) {
    if (dir.x < 0.0)
      invDir.x = -invEps;
    else
      invDir.x = invEps;
  }
  else
    invDir.x = 1.0 / dir.x;
  
  if (fabs(dir.y) < eps) {
    if (dir.y < 0.0)
      invDir.y = -invEps;
    else
      invDir.y = invEps;
  }
  else
    invDir.y = 1.0 / dir.y;
  
  if (fabs(dir.z) < eps) {
    if (dir.z < 0.0)
      invDir.z = -invEps;
    else
      invDir.z = invEps;
  }
  else
    invDir.z = 1.0 / dir.z;

  return;
}

void
PassingRaySet::Reset()
{
  for (int i=0; i < 3*Resolution*Resolution; i++)
    mDirectionalContributions[i] = 0;
  mRays = 0;
  mContributions = 0;
}
  
void
PassingRaySet::AddRay(const Ray &ray, const int contributions)
{
  int i = GetEntryIndex(ray.GetDir());
  mRays++;
  mContributions += contributions;
  mDirectionalContributions[i] += contributions;
}

int
PassingRaySet::GetEntryIndex(const Vector3 &direction) const
{
  // get face
  int axis = direction.DrivingAxis();
  Vector3 dir;
  float k = direction[axis];
  if ( k < 0.0f)
    k = -k;

  dir = direction/k;
  float x, y;
  dir.ExtractVerts(&x, &y, axis);
  int ix = (x + 1.0f)*0.5f*Resolution;
  int iy = (y + 1.0f)*0.5f*Resolution;

  return Resolution*(Resolution*axis + iy) + ix;
}

int Ray::ClassifyPlane(const Plane3 &plane, 
                                           const float minT, 
                                           const float maxT) const
{
        const Vector3 entp = Extrap(minT);
        const Vector3 extp = Extrap(maxT);
  
        const int entSide = plane.Side(entp);
        const int extSide = plane.Side(extp);

        if (entSide < 0)
        {
                if (extSide >= 0)
                {
                        return BACK_FRONT;
                }
                return BACK;
        }
        else if (entSide > 0)
        {
                if (extSide <= 0)
                        return FRONT_BACK;

                return FRONT;
        }
        else if (entSide == 0)
        {
                if (extSide > 0)
                        return BACK_FRONT;
                else if (extSide < 0)
                        return FRONT_BACK;
        }
        
        return COINCIDENT;
}

ostream &
operator<<(ostream &s, const PassingRaySet &set)
{
  s<<"Ray Set #rays="<<set.mRays<<" #contributions="<<set.mContributions<<endl;
  for (int i=0; i < 3*sqr(PassingRaySet::Resolution); i++)
    s<<set.mDirectionalContributions[i]<<" ";
  s<<endl;
  return s;
}