public override bool Hit(RayTrace.Ray ray, float t_min, float t_max, ref HitRecord rec)
{
var oc = ray.origin - center;
float a = Vector3.Dot(ray.direction, ray.direction);
float b = 2f * Vector3.Dot(oc, ray.direction);
float c = Vector3.Dot(oc, oc) - radius * radius;
float discriminant = b * b - 4 * a * c;
if (discriminant > 0)
{
float temp = (-b - Mathf.Sqrt(discriminant)) / a * 0.5f;
if (temp < t_max && temp > t_min)
{
rec.t = temp;
rec.p = ray.GetPoint(rec.t);
rec.normal = (rec.p - center).normalized;
rec.material = material;
return(true);
}
temp = (-b + Mathf.Sqrt(discriminant)) / a * 0.5f;
if (temp < t_max && temp > t_min)
{
rec.t = temp;
rec.p = ray.GetPoint(rec.t);
rec.normal = (rec.p - center).normalized;
rec.material = material;
return(true);
}
}
return(false);
}
static Color GetColorForTestNormal(Ray ray)
{
float t = HitSphereForTestNormal(new Vector3(0, 0, -1), 0.5f, ray);
if (t > 0)
{
Vector3 normal = Vector3.Normalize(ray.GetPoint(t) - new Vector3(0, 0, -1));
return(0.5f * new Color(normal.x + 1, normal.y + 1, normal.z + 1, 2f));
}
t = 0.5f * ray.normalDirection.y + 1f;
return((1 - t) * new Color(1, 1, 1) + t * new Color(0.5f, 0.7f, 1));
}