//// ===========================================================================================================
//// Methods
//// ===========================================================================================================
public static IntersectionState Create(Intersection hit, Ray ray, IntersectionList intersections)
{
// Copy the intersection's properties for convenience.
double t = hit.T;
Shape shape = hit.Shape;
// Precompute some useful values.
Point point = ray.PositionAt(hit.T);
Vector eye = -ray.Direction;
Vector normal = shape.NormalAt(point, hit);
bool isInside = false;
if (normal.Dot(eye) < 0)
{
isInside = true;
normal = -normal;
}
Point overPoint = point + (normal * NumberExtensions.Epsilon);
Point underPoint = point - (normal * NumberExtensions.Epsilon);
Vector reflection = ray.Direction.Reflect(normal);
// Calculate the refraction values.
var containers = new List <Shape>();
double n1 = 1.0;
double n2 = 1.0;
foreach (Intersection intersection in intersections)
{
if (intersection == hit)
{
n1 = containers.Count == 0 ? 1.0 : containers[^ 1].Material.RefractiveIndex;
public bool IsShadowed(Point point, Light light)
{
Vector pointToLightVector = light.Position - point;
double distance = pointToLightVector.Magnitude;
Vector direction = pointToLightVector.Normalize();
var ray = new Ray(point, direction);
IntersectionList intersections = Intersect(ray);
Intersection? hit = intersections.Hit;
return(hit != null && hit.T < distance && !hit.Shape.IsShadowHidden);
}
/// <summary>
/// Iterates over all of the shapes in the world and returns all of the hits for the specified ray.
/// </summary>
/// <param name="ray">The ray to use for hit testing.</param>
/// <returns>The list of all intersections for the specified ray.</returns>
public IntersectionList Intersect(Ray ray)
{
var hits = new IntersectionList();
foreach (Shape shape in Shapes)
{
IntersectionList shapeHits = shape.Intersect(ray);
hits.AddRange(shapeHits);
}
return(hits);
}
/// <summary>
/// Finds the color of the first shape that is hit for the given ray.
/// </summary>
/// <param name="ray">The ray to use for hit testing.</param>
/// <param name="maxRecursion">The maximum number of additional rays to use for reflection.</param>
/// <returns>
/// The color for the part of the shape that the ray hits, or <see cref="Colors.Black"/> if no shape is hit.
/// </returns>
public Color ColorAt(Ray ray, int maxRecursion = MaxRecursion)
{
IntersectionList intersections = Intersect(ray);
Intersection? hit = intersections.Hit;
if (hit == null)
{
return(Colors.Black);
}
var state = IntersectionState.Create(hit, ray, intersections);
Color color = ShadeHit(state, maxRecursion);
return(color);
}
