public bool Hit(Ray ray, float t0, float t1, out HitRect hitrect)
{
hitrect = new HitRect();
bool hit_anything = false;
float closest_so_far = t1;
foreach (var p in list)
{
if (p.Hit(ray, t0, closest_so_far, out HitRect temp_rec))
{
hit_anything = true;
closest_so_far = temp_rec.t;
hitrect.t = temp_rec.t;
hitrect.point = temp_rec.point;
hitrect.normal = temp_rec.normal;
}
}
return(hit_anything);
}
public bool Hit(Ray ray, float t0, float t1, out HitRect rect)
{
rect = new HitRect();
// center ->c
// ray p(t) = ->o + t * ->d
// ->oc = ->o - ->c
Vector3 o_c = ray.Origin - center;
// a = ->o・->o
float a = Vector3.Dot(ray.Direction, ray.Direction);
// b = 2(->d・->oc))
float b = 2.0f * Vector3.Dot(ray.Direction, o_c);
// c = (->oc・->oc) - r^2
float c = Vector3.Dot(o_c, o_c) - (float)Math.Pow(radius, 2);
// D = b^2 - 4ac
float D = b * b - 4 * a * c;
// hit
if (D > 0)
{
// y = (-b - √D) / 2a
float root = (float)Math.Sqrt(D);
float temp = (-b - root) / (2.0f * a);
if (temp < t1 && temp > t0)
{
rect.t = temp;
rect.point = ray.At(rect.t);
rect.normal = (rect.point - center) / radius;
return(true);
}
// y = (-b + √D) / 2a
temp = (-b + root) / (2.0f * a);
if (temp < t1 && temp > t0)
{
rect.t = temp;
rect.point = ray.At(rect.t);
rect.normal = (rect.point - center) / radius;
return(true);
}
}
return(false);
}