public Sphere(Vector position, double radius, MaterialFunc materialFunc)
: base(materialFunc)
{
this.Position = position;
this.Radius = radius;
box = createBoundingBox();
}
public Triangle(Material material, params Vector[] vertices)
: base(material)
{
if (vertices.Length != 3)
{
throw new ArgumentException(string.Format("Cannot construct triangle from {0} vertices", vertices.Length));
}
else
{
this.Vertices = new Vector[3];
vertices.CopyTo(this.Vertices, 0);
plane = new Plane(vertices, material);
double test = vertices[0].Dot(plane.Normal) + plane.D;
test = vertices[1].Dot(plane.Normal) + plane.D;
test = vertices[2].Dot(plane.Normal) + plane.D;
double x = test;
bounds = new BoundingPlane[3];
Vector n;
// get bounding plane containing v1, v0
// normal must be perpendicular to v1 - v0
n = plane.Normal.Cross(vertices[1] - vertices[0]);
bounds[0].Normal = n;
// shift plane so that v0 (thus also v1) lies in the plane
bounds[0].d = -vertices[0].Dot(n);
test = vertices[0].Dot(bounds[0].Normal) + bounds[0].d;
test = vertices[1].Dot(bounds[0].Normal) + bounds[0].d;
// make plane positive side face inside of the triangle
if (vertices[2].Dot(n) + bounds[0].d < 0)
bounds[0].Invert();
n = plane.Normal.Cross(vertices[2] - vertices[1]);
bounds[1].Normal = n;
bounds[1].d = -vertices[1].Dot(n);
test = vertices[2].Dot(bounds[1].Normal) + bounds[1].d;
test = vertices[1].Dot(bounds[1].Normal) + bounds[1].d;
if (vertices[0].Dot(n) + bounds[1].d < 0)
bounds[1].Invert();
n = plane.Normal.Cross(vertices[0] - vertices[2]);
bounds[2].Normal = n;
bounds[2].d = -vertices[2].Dot(n);
test = vertices[0].Dot(bounds[2].Normal) + bounds[2].d;
test = vertices[2].Dot(bounds[2].Normal) + bounds[2].d;
if (vertices[1].Dot(n) + bounds[2].d < 0)
bounds[2].Invert();
double y = test;
box = createBoundingBox();
}
}
public bool Intersects(BoundingBox other)
{
if (this == BoundingBox.Infinite || other == BoundingBox.Infinite)
return true;
// we are likely to pass all tests and intersect if the boxes are real close
double e = Constants.Epsilon*10;
// try to find a separating plane, do it for all 6 planes
if (this.LeftTopFront.X - e > other.RightBottomBack.X) return false;
if (this.RightBottomBack.X + e < other.LeftTopFront.X) return false;
if (this.LeftTopFront.Y - e > other.RightBottomBack.Y) return false;
if (this.RightBottomBack.Y + e < other.LeftTopFront.Y) return false;
if (this.LeftTopFront.Z - e > other.RightBottomBack.Z) return false;
if (this.RightBottomBack.Z + e < other.LeftTopFront.Z) return false;
// cannot separate -> they intersect
return true;
}
/// <summary>
/// Splits node's primitives into 8 new children nodes.
/// </summary>
private void split()
{
if (boundingBox == null)
throw new Exception("Cannot split null bounding box");
try
{
this.childs = new OctreeNode[8];
for (int i = 0; i < 8; i++)
{
childs[i] = new OctreeNode();
childs[i].boundingBox = new BoundingBox(new Vector(), new Vector());
}
double dx2 = (boundingBox.RightBottomBack.X - boundingBox.LeftTopFront.X) / 2;
double dy2 = (boundingBox.RightBottomBack.Y - boundingBox.LeftTopFront.Y) / 2;
double dz2 = (boundingBox.RightBottomBack.Z - boundingBox.LeftTopFront.Z) / 2;
childs[0].boundingBox.LeftTopFront = boundingBox.LeftTopFront;
childs[1].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, 0, 0);
childs[2].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(0, dy2, 0);
childs[3].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, dy2, 0);
childs[4].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(0, 0, dz2);
childs[5].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, 0, dz2);
childs[6].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(0, dy2, dz2);
childs[7].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, dy2, dz2);
Vector sizeVector = new Vector(dx2, dy2, dz2);
// all childs same size
for (int i = 0; i < 8; i++)
{
childs[i].boundingBox.RightBottomBack =
childs[i].boundingBox.LeftTopFront + sizeVector;
}
// distribute primitives into children
foreach (Primitive primitive in primitives)
{
// primitive may fall into multiple children at the same time
// ideally it will fall in only 1 child
for (int i = 0; i < 8; i++)
{
if (primitive.BoundingBox.Intersects(childs[i].boundingBox))
{
childs[i].Add(primitive);
}
}
}
primitives = null;
}
catch
{
// in case of exception clean up any inconsistencies
this.childs = null;
this.boundingBox = BoundingBox.Zero;
throw;
}
}
public BoxPrimitive(Vector leftTopFront, Vector rightBottomBack, MaterialFunc matFunc)
: base(matFunc)
{
box = new BoundingBox(leftTopFront, rightBottomBack);
center = Vector.Combine(leftTopFront, 1.0, (rightBottomBack - leftTopFront), 0.5);
}
/// <summary>
/// Returns whether bounding box is relatively large to reference bouding box.
/// </summary>
private bool isBigBoundingBox(BoundingBox tested, BoundingBox reference)
{
double threshold = 4;
Vector extent = tested.RightBottomBack - tested.LeftTopFront;
Vector referenceExtent = reference.RightBottomBack - reference.LeftTopFront;
// any dimension large enough
return
extent.X * threshold > referenceExtent.X ||
extent.Y * threshold > referenceExtent.Y ||
extent.Z * threshold > referenceExtent.Z;
}
