//! Check if the given ray intersect the box.
bool intersect(const Ray<Type> & a_ray, Type & tmin, Type & tmax) const
{
// Amy Williams, Steve Barrus, R. Keith Morley, and Peter Shirley
// "An Efficient and Robust Ray-Box Intersection Algorithm"
// Journal of graphics tools, 10(1):49-54, 2005
if( isEmpty() ) return false;
Vec3<Type> inv_direction(1/a_ray.getDirection()[0], 1/a_ray.getDirection()[1], 1/a_ray.getDirection()[2]);
Vec3<int> sign( inv_direction[0] < 0, inv_direction[1] < 0, inv_direction[2] < 0);
tmin = ((sign[0] ? m_max : m_min).x() - a_ray.getOrigin().x()) * inv_direction.x();
tmax = (((1-sign[0]) ? m_max : m_min).x() - a_ray.getOrigin().x()) * inv_direction.x();
Type tymin = ((sign[1] ? m_max : m_min).y() - a_ray.getOrigin().y()) * inv_direction.y();
Type tymax = (((1-sign[1]) ? m_max : m_min).y() - a_ray.getOrigin().y()) * inv_direction.y();
if( (tmin > tymax) || (tymin > tmax) ) return false;
if(tymin > tmin) tmin = tymin;
if(tymax < tmax) tmax = tymax;
Type tzmin = ((sign[2] ? m_max : m_min).z() - a_ray.getOrigin().z()) * inv_direction.z();
Type tzmax = (((1-sign[2]) ? m_max : m_min).z() - a_ray.getOrigin().z()) * inv_direction.z();
if( (tmin > tzmax) || (tzmin > tmax) ) return false;
if (tzmin > tmin) tmin = tzmin;
if (tzmax < tmax) tmax = tzmax;
return (tmin >= 0 && tmax >= 1);
}
bool intersectRayBBox(const Vec3r& orig, const Vec3r& dir, // ray origin and direction
const Vec3r& boxMin, const Vec3r& boxMax, // the bbox
real t0, real t1,
real& tmin, real& tmax, // I0=orig+tmin*dir is the first intersection, I1=orig+tmax*dir is the second intersection
real epsilon){
float tymin, tymax, tzmin, tzmax;
Vec3r inv_direction(1.0/dir[0], 1.0/dir[1], 1.0/dir[2]);
int sign[3];
sign[0] = (inv_direction.x() < 0);
sign[1] = (inv_direction.y() < 0);
sign[2] = (inv_direction.z() < 0);
Vec3r bounds[2];
bounds[0] = boxMin;
bounds[1] = boxMax;
tmin = (bounds[sign[0]].x() - orig.x()) * inv_direction.x();
tmax = (bounds[1-sign[0]].x() - orig.x()) * inv_direction.x();
tymin = (bounds[sign[1]].y() - orig.y()) * inv_direction.y();
tymax = (bounds[1-sign[1]].y() - orig.y()) * inv_direction.y();
if ( (tmin > tymax) || (tymin > tmax) )
return false;
if (tymin > tmin)
tmin = tymin;
if (tymax < tmax)
tmax = tymax;
tzmin = (bounds[sign[2]].z() - orig.z()) * inv_direction.z();
tzmax = (bounds[1-sign[2]].z() - orig.z()) * inv_direction.z();
if ( (tmin > tzmax) || (tzmin > tmax) )
return false;
if (tzmin > tmin)
tmin = tzmin;
if (tzmax < tmax)
tmax = tzmax;
return ( (tmin < t1) && (tmax > t0) );
}
