double
circle::intersect(ray const& r) const
{
double t;
point3d v1, v2;
v1=normalize(p1_-center_);
v2=normalize(p2_-center_);
point3d n=normalenvektor(v1, v2);
double s=scaleproduct(n, center_);
point3d dir=normalize(r.getDir());
if (scaleproduct(n, dir)!=0)
{
double temp=(scaleproduct(n, r.getOrigin())+s)/scaleproduct(n, dir);
point3d schnitt=r.getOrigin()+temp*dir;
//std::cout<<"schnitt: "<<schnitt<<std::endl;
if (is_inside(schnitt))
{
//std::cout<<"Schnittpunkt mit dem Kreis"<<std::endl;
return t=temp;
}
else
{
//std::cout<<"Schnittpunkt mit Ebene aber nicht mit Kreis"<<std::endl;
return t=-1;
}
}
else
{
//std::cout<<"Kein Schnittpunkt mit Kreisebene"<<std::endl;
return t=-1;
}
}
//! Intersect ray and sphere, returning true if there is an intersection.
bool intersect(const ray<Type>& r, Type& tmin, Type& tmax) const
{
const vec3<Type> r_to_s = r.getOrigin() - m_center;
//Compute A, B and C coefficients
const Type A = r.getDirection().sqrLength();
const Type B = 2.0f * r_to_s.dot(r.getDirection());
const Type C = r_to_s.sqrLength() - m_radius * m_radius;
//Find discriminant
Type disc = B * B - 4.0 * A * C;
// if discriminant is negative there are no real roots
if (disc < 0.0)
return false;
disc = (Type)std::sqrt((double)disc);
tmin = (-B + disc) / (2.0 * A);
tmax = (-B - disc) / (2.0 * A);
// check if we're inside it
if ((tmin < 0.0 && tmax > 0) || (tmin > 0 && tmax < 0))
return false;
if (tmin > tmax)
std::swap(tmin, tmax);
return (tmin > 0);
}
