private HitInfo FindHitObject(Ray ray, Geometry originator, HitMode mode)
{
Vector3D intersectionPoint = new Vector3D(double.MaxValue, double.MaxValue, double.MaxValue);
HitInfo info = new HitInfo(null, intersectionPoint, ray);
double distance = double.MaxValue;
foreach (Geometry geometry in Scene.Geometries)
{
if (geometry != originator && geometry.Intersects(ray, ref intersectionPoint))
{
double distanceToObject = Vector3D.Subtract(ray.Source, intersectionPoint).Length;
if (distanceToObject < distance)
{
info.hitPoint = intersectionPoint;
distance = distanceToObject;
info.hitObject = geometry;
if (mode == HitMode.Any)
{
break;
}
}
}
}
return(info);
}
private bool InShadow(HitInfo info, Vector3D lightLocation, Vector3D lightNormal)
{
Ray shadowRay = new Ray(lightLocation, lightNormal);
HitInfo shadingInfo = FindHitObject(shadowRay, info.hitObject, HitMode.Closest);
if (shadingInfo.hitObject != null &&
Vector3D.Subtract(lightLocation, info.hitPoint).Length >
Vector3D.Subtract(lightLocation, shadingInfo.hitPoint).Length)
{
return(true);
}
return(false);
}
/// <summary>
/// Calculate the intesection point between the ray and the plane of the rectangle.
/// </summary>
/// <param name="ray">The ray to check</param>
/// <param name="intersectionPoint">The result intersection point</param>
/// <returns>True if the intersection is in the rectangle</returns>
override public bool Intersects(Ray ray, ref Vector3D intersectionPoint)
{
var normalDotProduct = Vector3D.DotProduct(Normal, ray.Direction);
// Do the intersection test as for a Plane.
if (normalDotProduct != 0)
{
//Give the right orientation to the normal vector
if (normalDotProduct > 0)
{
normal = -Normal;
normalDotProduct = -normalDotProduct;
}
Vector3D Point = (Vector3D)Point1;
double t = (Vector3D.DotProduct(Normal, (Vector3D.Subtract(Point, ray.Source)))) / normalDotProduct;
if (t >= 0)
{
intersectionPoint = ray.Source + (ray.Direction * t);
var vec1 = (Point3D)intersectionPoint - Point1;
var vec2 = Point2 - Point1;
var vec3 = Point4 - Point1;
var alpha = Vector3D.DotProduct(vec1, vec2) / vec2.LengthSquared;
var beta = Vector3D.DotProduct(vec1, vec3) / vec3.LengthSquared;
if (alpha >= 0 && alpha <= 1 && beta >= 0 && beta <= 1)
{
return(true);
}
}
}
return(false);
}
/// <summary>
/// Calculate the intesection point between the ray and the plane of the rectangle.
/// </summary>
/// <param name="ray">The ray to check</param>
/// <param name="intersectionPoint">The result intersection point</param>
/// <returns>True if the intersection is in the rectangle</returns>
override public bool Intersects(Ray ray, ref Vector3D intersectionPoint)
{
Vector3D tempIntersectionPoint = new Vector3D(double.MaxValue, double.MaxValue, double.MaxValue);
double distance = double.MaxValue;
bool doesIntersect = false;
foreach (Rectangle rectangle in faces)
{
if (rectangle.Intersects(ray, ref tempIntersectionPoint))
{
doesIntersect = true;
double distanceToFace = Vector3D.Subtract(ray.Source, tempIntersectionPoint).Length;
if (distanceToFace < distance)
{
distance = distanceToFace;
normalsDictionary.TryAdd(intersectionPoint, rectangle.Normal);
}
}
}
return(doesIntersect);
}
public static Ray FromStartAndEndPoints(Vector3D start, Vector3D end)
{
return(new Ray(start, Vector3D.Subtract(end, start)));
}