public override bool Hit(Ray r, double tMin, double tMax, ref HitRecord record)
{
var hitAnything = false;
var closestSoFar = tMax;
foreach (var t in _hitables)
{
if (!t.Hit(r, tMin, closestSoFar, ref record))
{
continue;
}
hitAnything = true;
closestSoFar = record.T;
}
return(hitAnything);
}
static Vec3 Color(Ray ray, HitableItems world, int depth)
{
var record = new HitRecord();
// Ignore close hits as they're likely the cause of rounding errors
// with t values. Not ignoring causes an undesirable visual effect
// called the shadow acne.
if (world.Hit(ray, 0.001, double.MaxValue, ref record))
{
return((depth < 50 && record.Material.Scatter(ray, record, out Vec3 attenuation, out Ray scatterRay))
? attenuation * Color(scatterRay, world, depth + 1)
: ZeroVector);
}
var unitDirection = Vec3.UnitVector(ray.Direction);
var t = 0.5 * (unitDirection.Y + 1);
return((1 - t) * UnitVector + t * Background);
}
public bool hit(Ray r, float t_min, float t_max, ref HitRecord rec)
{
HitRecord temp_rec = new HitRecord();
bool hit_something = false;
float closest_so_far = t_max;
foreach (Hitable h in this.hitableList)
{
if (h == null)
{
continue;
}
if (h.hit(r, t_min, closest_so_far, ref temp_rec))
{
hit_something = true;
closest_so_far = temp_rec.t;
rec = temp_rec;
}
}
return(hit_something);
}
public override bool Hit(Ray r, double tMin, double tMax, ref HitRecord record)
{
var oc = r.Origin - _center;
var a = Vec3.Dot(r.Direction, r.Direction);
var b = Vec3.Dot(oc, r.Direction);
var c = Vec3.Dot(oc, oc) - _radius * _radius;
var discriminant = b * b - a * c;
if (discriminant > 0)
{
var sqrtDiscriminant = Math.Sqrt(discriminant);
var solution1 = (-b - sqrtDiscriminant) / a;
if (solution1 < tMax && solution1 > tMin)
{
record.T = solution1;
record.PointOfIntersection = r.PointAtParameter(record.T);
// Normal is computed by computing the vector center to
// point of intersection Dividing by radius causes this
// vector to become a unit vector.
record.Normal = (record.PointOfIntersection - _center) / _radius;
record.Material = _material;
return(true);
}
var solution2 = (-b + sqrtDiscriminant) / a;
if (solution2 < tMax && solution2 > tMin)
{
record.T = solution2;
record.PointOfIntersection = r.PointAtParameter(record.T);
record.Normal = (record.PointOfIntersection - _center) / _radius;
record.Material = _material;
return(true);
}
}
return(false);
}
static private Vector3 ch8_color(Ray r, HitableList hitableList, int depth)
{
HitRecord rec = new HitRecord();
if (hitableList.hit(r, 0.0001f, float.MaxValue, ref rec))
{
Ray scattered = null;
Vector3 attenuation = null;
if (depth > 0 && rec.mat.scatter(r, rec, ref attenuation, ref scattered))
{
return(attenuation * ch8_color(scattered, hitableList, depth - 1));
}
else
{
return(new Vector3(0, 0, 0));
}
}
else
{
float t = 0.5f * (r.direction().normalized.y() + 1);
return(new Vector3(1.0f, 1.0f, 1.0f) * (1 - t) + new Vector3(0.5f, 0.7f, 1.0f) * t);
}
}
static Vec3 color(Ray r, IHitable world, int depth)
{
HitRecord rec = new HitRecord();
if (world.hit(r, 0.001F, float.MaxValue, ref rec))
{
Ray scattered = new Ray();
Vec3 attenuation = new Vec3();
if (depth < 50 && rec.mat.scatter(r, rec, ref attenuation, ref scattered))
{
return(attenuation * color(scattered, world, depth + 1));
}
else
{
return(new Vec3(0, 0, 0));
}
}
else
{
Vec3 unitDirection = Vec3.unitVector(r.direction());
float t = 0.5F * (unitDirection.y() + 1.0F);
return((1.0F - t) * new Vec3(1.0F, 1.0F, 1.0F) + t * new Vec3(0.5F, 0.7F, 1.0F));
}
}
public abstract bool Hit(Ray r, double tMin, double tMax, ref HitRecord record);
public abstract bool Scatter(Ray incidentRay, HitRecord rec, out Vec3 attenuation, out Ray scatteredRay);
