public override bool Hit(RTRay ray, float t_min, float t_max, out HitRecord rec)
{
rec = new HitRecord();
Vector3 oc = ray.origin - center;
float a = Vector3.Dot(ray.direction, ray.direction);
float b = 2.0f * Vector3.Dot(oc, ray.direction);
float c = Vector3.Dot(oc, oc) - radius * radius;
float discriminant = b * b - 4 * a * c;
if (discriminant < 0)
{
return(false);
}
else
{
float t = (-b - Mathf.Sqrt(discriminant)) / (2 * a);
if (t < t_max && t > t_min)
{
rec.t = t;
rec.p = ray.PointAt(t);
rec.n = (rec.p - center) / radius;
rec.material = material;
return(true);
}
t = (-b + Mathf.Sqrt(discriminant)) / (2 * a);
if (t < t_max && t > t_min)
{
rec.t = t;
rec.p = ray.PointAt(t);
rec.n = (rec.p - center) / radius;
rec.material = material;
return(true);
}
return(false);
}
}
public override Color GetColor(RTRay ray, int depth)
{
Vector3 sphereCenter = new Vector3(0, 0, -1);
float sphereRadius = 0.5f;
float hit = HitSphere(sphereCenter, sphereRadius, ray);
if (hit >= 0)
{
Vector3 n = (ray.PointAt(hit) - sphereCenter).normalized;
return(new Color((n.x + 1) * 0.5f, (n.y + 1) * 0.5f, (n.z + 1) * 0.5f));
}
return(GetBackgroundColor(ray));
}