public bool Hit(Ray r, float t0, float t1, ref Hit_Record rec)
{
var t = (k - r.Origin.X) / r.Direction.X;
if (t < t0 || t > t1)
{
return(false);
}
var y = r.Origin.Y + t * r.Direction.Y;
var z = r.Origin.Z + t * r.Direction.Z;
if (y < y0 || y > y1 || z < z0 || z > z1)
{
return(false);
}
rec.U = (y - y0) / (y1 - y0);
rec.V = (z - z0) / (z1 - z0);
rec.T = t;
var outward_normal = new Vector3(1, 0, 0);
rec.Set_Face_Normal(r, outward_normal);
rec.Mat_ptr = mp;
rec.P = r.At(t);
return(true);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
var origin = r.Origin;
var direction = r.Direction;
origin.X = cos_theta * r.Origin.X - sin_theta * r.Origin.Z;
origin.Z = sin_theta * r.Origin.X + cos_theta * r.Origin.Z;
direction.X = cos_theta * r.Direction.X - sin_theta * r.Direction.Z;
direction.Z = sin_theta * r.Direction.X + cos_theta * r.Direction.Z;
Ray rotated_r = new Ray(origin, direction, r.Time);
if (!ptr.Hit(rotated_r, t_min, t_max, ref rec))
{
return(false);
}
var p = rec.P;
var normal = rec.Normal;
p.X = cos_theta * rec.P.X + sin_theta * rec.P.Z;
p.Z = -sin_theta * rec.P.X + cos_theta * rec.P.Z;
normal.X = cos_theta * rec.Normal.X + sin_theta * rec.Normal.Z;
normal.Z = -sin_theta * rec.Normal.X + cos_theta * rec.Normal.Z;
rec.P = p;
rec.Set_Face_Normal(rotated_r, normal);
return(true);
}
public bool Hit(Ray r, float t0, float t1, ref Hit_Record rec)
{
var t = (k - r.Origin.Y) / r.Direction.Y;
if (t < t0 || t > t1)
{
return(false);
}
var x = r.Origin.X + t * r.Direction.X;
var z = r.Origin.Z + t * r.Direction.Z;
if (x < x0 || x > x1 || z < z0 || z > z1)
{
return(false);
}
rec.U = (x - x0) / (x1 - x0);
rec.V = (z - z0) / (z1 - z0);
rec.T = t;
var outward_normal = new Vector3(0, 1, 0);
rec.Set_Face_Normal(r, outward_normal);
rec.Mat_ptr = mp;
rec.P = r.At(t);
return(true);
}
static Vector3 Ray_color(Ray r, Vector3 background, HitTable world, int depth)
{
Hit_Record rec = default;
// If we've exceeded the ray bounce limit, no more light is gathered.
if (depth <= 0)
{
return(Vector3.Zero);
}
// If the ray hits nothing, return the background color.
if (!world.Hit(r, 0.001f, Helpers.Infinity, ref rec))
{
return(background);
}
Ray scattered;
Vector3 attenuation;
Vector3 emitted = rec.Mat_ptr.Emitted(rec.U, rec.V, rec.P);
if (!rec.Mat_ptr.Scatter(r, rec, out attenuation, out scattered))
{
return(emitted);
}
return(emitted + attenuation * Ray_color(scattered, background, world, depth - 1));
}
public override bool Scatter(Ray r_in, Hit_Record rec, out Vector3 attenuation, out Ray scattered)
{
attenuation = Vector3.One;
float etai_over_etat = (rec.Front_face) ? (1.0f / Ref_idx) : (Ref_idx);
Vector3 unit_direction = Vector3.Normalize(r_in.Direction);
float cos_theta = Math.Min(Vector3.Dot(-unit_direction, rec.Normal), 1.0f);
float sin_theta = (float)Math.Sqrt(1.0f - cos_theta * cos_theta);
if (etai_over_etat * sin_theta > 1.0f)
{
Vector3 reflected = Helpers.Reflect(unit_direction, rec.Normal);
scattered = new Ray(rec.P, reflected);
return(true);
}
float reflect_prob = Helpers.Schlick(cos_theta, etai_over_etat);
if (Helpers.random.NextDouble() < reflect_prob)
{
Vector3 reflected = Helpers.Reflect(unit_direction, rec.Normal);
scattered = new Ray(rec.P, reflected);
return(true);
}
Vector3 refracted = Helpers.Refract(unit_direction, rec.Normal, etai_over_etat);
scattered = new Ray(rec.P, refracted);
return(true);
}
public override bool Scatter(Ray r_in, Hit_Record rec, out Vector3 attenuation, out Ray scattered)
{
Vector3 scatter_direction = rec.Normal + Helpers.Random_unit_Vector();
scattered = new Ray(rec.P, scatter_direction, r_in.Time);
attenuation = this.Albedo.Value(rec.U, rec.V, rec.P);
return(true);
}
public override bool Scatter(Ray r_in, Hit_Record rec, out Vector3 attenuation, out Ray scattered)
{
Vector3 unit_vector = Vector3.Normalize(r_in.Direction);
Vector3 reflected = Helpers.Reflect(unit_vector, rec.Normal);
scattered = new Ray(rec.P, reflected + fuzz * Helpers.Random_in_unit_sphere());
attenuation = this.Albedo;
return(Vector3.Dot(scattered.Direction, rec.Normal) > 0);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
if (!this.box.Hit(r, t_min, t_max))
{
return(false);
}
bool hit_left = left.Hit(r, t_min, t_max, ref rec);
bool hit_right = right.Hit(r, t_min, hit_left ? rec.T : t_max, ref rec);
return(hit_left || hit_right);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
Ray moved_r = new Ray(r.Origin - offset, r.Direction, r.Time);
if (!ptr.Hit(moved_r, t_min, t_max, ref rec))
{
return(false);
}
rec.P += offset;
rec.Set_Face_Normal(moved_r, rec.Normal);
return(true);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
Hit_Record temp_rec = default;
bool hit_anything = false;
float closest_so_far = t_max;
foreach (var o in this.Objects)
{
if (o.Hit(r, t_min, closest_so_far, ref temp_rec))
{
hit_anything = true;
closest_so_far = temp_rec.T;
rec = temp_rec;
}
}
return(hit_anything);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
Vector3 oc = r.Origin - this.Center;
float a = r.Direction.LengthSquared();
float half_b = Vector3.Dot(oc, r.Direction);
float c = oc.LengthSquared() - this.Radius * this.Radius;
float discriminant = half_b * half_b - a * c;
if (discriminant > 0)
{
float root = (float)Math.Sqrt(discriminant);
float temp = (-half_b - root) / a;
if (temp < t_max && temp > t_min)
{
rec.T = temp;
rec.P = r.At(rec.T);
Vector3 outward_normal = (rec.P - this.Center) / this.Radius;
rec.Set_Face_Normal(r, outward_normal);
rec.Mat_ptr = Material;
this.Get_sphere_uv((rec.P - this.Center) / this.Radius, out rec.U, out rec.V);
return(true);
}
temp = (-half_b + root) / a;
if (temp < t_max && temp > t_min)
{
rec.T = temp;
rec.P = r.At(rec.T);
Vector3 outward_normal = (rec.P - this.Center) / this.Radius;
rec.Set_Face_Normal(r, outward_normal);
rec.Mat_ptr = Material;
this.Get_sphere_uv((rec.P - this.Center) / this.Radius, out rec.U, out rec.V);
return(true);
}
}
return(false);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
Vector3 oc = r.Origin - this.Center(r.Time);
var a = r.Direction.LengthSquared();
var half_b = Vector3.Dot(oc, r.Direction);
var c = oc.LengthSquared() - radius * radius;
var discriminant = half_b * half_b - a * c;
if (discriminant > 0)
{
var root = (float)Math.Sqrt(discriminant);
var temp = (-half_b - root) / a;
if (temp < t_max && temp > t_min)
{
rec.T = temp;
rec.P = r.At(rec.T);
var outward_normal = (rec.P - this.Center(r.Time)) / radius;
rec.Set_Face_Normal(r, outward_normal);
rec.Mat_ptr = mat_ptr;
return(true);
}
temp = (-half_b + root) / a;
if (temp < t_max && temp > t_min)
{
rec.T = temp;
rec.P = r.At(rec.T);
var outward_normal = (rec.P - this.Center(r.Time)) / radius;
rec.Set_Face_Normal(r, outward_normal);
rec.Mat_ptr = mat_ptr;
return(true);
}
}
return(false);
}
public bool Hit(Ray r, float t0, float t1, ref Hit_Record rec)
{
return(sides.Hit(r, t0, t1, ref rec));
}
public override bool Scatter(Ray r_in, Hit_Record rec, out Vector3 attenuation, out Ray scattered)
{
attenuation = default;
scattered = null;
return(false);
}
public abstract bool Scatter(Ray r_in, Hit_Record rec, out Vector3 attenuation, out Ray scattered);
public override bool Scatter(Ray r_in, Hit_Record rec, out Vector3 attenuation, out Ray scattered)
{
scattered = new Ray(rec.P, Helpers.Random_in_unit_sphere(), r_in.Time);
attenuation = albedo.Value(rec.U, rec.V, rec.P);
return(true);
}
public bool Hit(Ray r, float t_min, float t_max, ref Hit_Record rec)
{
// Print occasional samples when debugging. To enable, set enableDebug true.
const bool enableDebug = false;
bool debugging = enableDebug && ((float)Helpers.random.NextDouble() < 0.00001f);
Hit_Record rec1, rec2;
rec1 = rec2 = default;
if (!boundary.Hit(r, -Helpers.Infinity, Helpers.Infinity, ref rec1))
{
return(false);
}
if (!boundary.Hit(r, rec1.T + 0.0001f, Helpers.Infinity, ref rec2))
{
return(false);
}
if (debugging)
{
Console.WriteLine($"t0={rec1.T}, t1={rec2.T}");
}
if (rec1.T < t_min)
{
rec1.T = t_min;
}
if (rec2.T > t_max)
{
rec2.T = t_max;
}
if (rec1.T >= rec2.T)
{
return(false);
}
if (rec1.T < 0)
{
rec1.T = 0;
}
float ray_length = r.Direction.Length();
float distance_inside_boundary = (rec2.T - rec1.T) * ray_length;
float hit_distance = neg_inv_density * (float)Math.Log(Helpers.random.NextDouble());
if (hit_distance > distance_inside_boundary)
{
return(false);
}
rec.T = rec1.T + hit_distance / ray_length;
rec.P = r.At(rec.T);
if (debugging)
{
Console.WriteLine($"hit_distance = {hit_distance} \n " +
$"rec.t = {rec.T} \n" +
$"rec.p = {rec.P}");
}
rec.Normal = new Vector3(1, 0, 0); // arbitrary
rec.Front_face = true; // also arbitrary
rec.Mat_ptr = phase_function;
return(true);
}
