public override IRayHit Intersect(IRay ray)
{
IVector p = ray.Origin;
IVector u = ray.Direction;
IVector v = new Vector(this.Position, p);
float b = 2 * (v.Dot(u));
float c = v.Dot(v) - this.Radius.X * this.Radius.X;
float discriminant = b * b - 4 * c;
if (discriminant < 0)
{
return(null);
}
float timeMinus = (b * -1 - ((float)Math.Sqrt(discriminant))) / 2;
float timePlus = (b * -1 + ((float)Math.Sqrt(discriminant))) / 2;
if (timeMinus < 0 && timePlus < 0)
{
return(null);
}
IVector intersection;
IVector normal;
float timeIntersection;
bool incoming;
if (timeMinus < 0 && timePlus > 0)
{
timeIntersection = timePlus;
intersection = ray.GetEndAt(timePlus);
normal = new Vector(intersection, this.Position);
incoming = false;
}
else
{
timeIntersection = timeMinus;
intersection = ray.GetEndAt(timeMinus);
normal = new Vector(this.Position, intersection);
incoming = true;
}
return(new RayHit(ray, this, this, normal.Normalize(), intersection, timeIntersection, incoming));
}
public override IRayHit Intersect(IRay ray)
{
float denominator = this.Normal.Dot(ray.Direction);
if (Math.Abs(denominator) > 0.0f)
{
IVector difference = this.Position.Minus(ray.Origin);
float t = difference.Dot(this.Normal) / denominator;
if (t > 0.0f)
{
IVector intersectionPoint = ray.GetEndAt(t);
return(new RayHit(ray, this, this, this.Normal, intersectionPoint, t, false));
}
}
return(null);
}