public override bool hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
Vec3 oc = r.origin() - center;
float a = r.direction().x() * r.direction().x() + r.direction().z() * r.direction().z();
float b = 2.0f * (oc.x() * r.direction().x() + oc.z() * r.direction().z());
float c = oc.x() * oc.x() + oc.z() * oc.z() - radius * radius;
float discriminant = b * b - 4 * a * c;
if (discriminant > 0.0f)
{
float temp = (-b - (float)Math.Sqrt(b * b - 4 * a * c)) / (2 * a);
if (temp < t_max && temp > t_min)
{
rec.t = temp;
rec.p = r.point_at_parameter(rec.t);
rec.normal = (rec.p - center) / radius;
rec.normal[1] = 0.0f;
rec.mat_type = mat_type;
Helper.get_sphere_uv(rec.p, ref rec.u, ref rec.v);
return(true);
}
temp = (-b + (float)Math.Sqrt(b * b - 4 * a * c)) / (2 * a);
if (temp < t_max && temp > t_min)
{
rec.t = temp;
rec.p = r.point_at_parameter(rec.t);
rec.normal = (rec.p - center) / radius;
rec.normal[1] = 0.0f;
rec.mat_type = mat_type;
Helper.get_sphere_uv(rec.p, ref rec.u, ref rec.v);
return(true);
}
}
return(false);
}
public override bool hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
// Perform a simplified Pythagorean in 3D to determine if
// the ray vector intersects with the sphere.
Vec3 oc = r.origin() - center;
float a = Vec3.dot(r.direction());
float b = Vec3.dot(oc, r.direction());
float c = Vec3.dot(oc) - radius * radius;
float discriminant = b * b - a * c;
if (discriminant > 0.0f)
{
float temp = (-b - (float)Math.Sqrt(b * b - a * c)) / a;
if (temp < t_max && temp > t_min)
{
rec.t = temp;
rec.p = r.point_at_parameter(rec.t);
rec.normal = (rec.p - center) / radius;
rec.mat_type = mat_type;
Helper.get_sphere_uv(rec.p, ref rec.u, ref rec.v);
return(true);
}
temp = (-b + (float)Math.Sqrt(b * b - a * c)) / a;
if (temp < t_max && temp > t_min)
{
rec.t = temp;
rec.p = r.point_at_parameter(rec.t);
rec.normal = (rec.p - center) / radius;
rec.mat_type = mat_type;
Helper.get_sphere_uv(rec.p, ref rec.u, ref rec.v);
return(true);
}
}
return(false);
}