public override bool Hit(Ray r, double tMin, double tMax, out Object3D rec)
{
var oc = r.Origin - Center;
var a = r.Direction.LengthSquared;
var halfB = Vector3.DotProduct(oc, r.Direction);
var c = oc.LengthSquared - Radius * Radius;
var discriminant = halfB * halfB - a * c;
if (discriminant > 0)
{
var root = Math.Sqrt(discriminant);
var temp = (-halfB - root) / a;
if (temp < tMax && temp > tMin)
{
rec = new Sphere(Center, Radius, Material);
rec.T = temp;
rec.P = r.At(rec.T);
var outwardNormal = (rec.P - Center) / Radius;
rec.SetFaceNormal(r, outwardNormal);
return(true);
}
temp = (-halfB + root) / a;
if (temp < tMax && temp > tMin)
{
rec = new Sphere(Center, Radius, Material);
rec.T = temp;
rec.P = r.At(rec.T);
var outwardNormal = (rec.P - Center) / Radius;
rec.SetFaceNormal(r, outwardNormal);
return(true);
}
}
rec = null;
return(false);
}
public abstract bool Hit(Ray r, double tMin, double tMax, out Object3D rec);
public static bool Hit(this IEnumerable <Object3D> source, Ray ray, double min, double max, out Object3D hit)
{
hit = null;
var hitDetected = false;
var closestSoFar = max;
foreach (var item in source)
{
if (!item.Hit(ray, min, closestSoFar, out var localHit))
{
continue;
}
hit = localHit;
hitDetected = true;
closestSoFar = localHit.T;
}
return(hitDetected);
}