public float[] CalculateQuaternion(int x, int y, bool camera_z)
{
// Map the current vector.
MapToSphere((float)x, (float)y, out currentVector, camera_z);
// Compute the cross product of the begin and end vectors.
Vertex cross = startVector.VectorProduct(currentVector);
// Is the perpendicular length essentially non-zero?
if (cross.Magnitude() > 1.0e-5)
{
// The quaternion is the transform.
//return new float[] { cross.X, cross.Y, cross.Z, startVector.ScalarProduct(currentVector) };
return(new float[] { cross.X, 0, cross.Z, startVector.ScalarProduct(currentVector) });
}
else
{
// Begin and end coincide, return identity.
return(new float[] { 0, 0, 0, 0 });
}
}
/// <summary>
/// This function tests to see if a ray interesects the polygon.
/// </summary>
/// <param name="ray">The ray you want to test.</param>
/// <returns>
/// The distance from the origin of the ray to the intersection, or -1 if there
/// is no intersection.
/// </returns>
private Intersection TestIntersection(Ray ray)
{
Intersection intersect = new Intersection();
// This code came from jgt intersect_triangle code (search dogpile for it).
foreach (Face face in faces)
{
// Assert that it's a triangle.
if (face.Count != 3)
{
continue;
}
// Find the point of intersection upon the plane, as a point 't' along
// the ray.
Vertex point1OnPlane = vertices[face.Indices[0].Vertex];
Vertex point2OnPlane = vertices[face.Indices[1].Vertex];
Vertex point3OnPlane = vertices[face.Indices[2].Vertex];
Vertex midpointOpp1 = (point2OnPlane + point3OnPlane) / 2;
Vertex midpointOpp2 = (point1OnPlane + point3OnPlane) / 2;
Vertex midpointOpp3 = (point1OnPlane + point2OnPlane) / 2;
Vertex planeNormal = face.GetSurfaceNormal(this);
Vertex diff = point1OnPlane - ray.origin;
float s1 = diff.ScalarProduct(planeNormal);
float s2 = ray.direction.ScalarProduct(planeNormal);
if (s2 == 0)
{
continue;
}
float t = s1 / s2;
if (t < 0)
{
continue;
}
float denomintor = planeNormal.ScalarProduct(ray.direction);
if (denomintor < 0.00001f && denomintor > -0.00001f)
{
continue; // doesn't intersect the plane.
}
// Vertex v = point1OnPlane - ray.origin;
// float t = (v.ScalarProduct(planeNormal)) / denomintor;
// Now we can get the point of intersection.
Vertex vIntersect = ray.origin + (ray.direction * t);
// Do my cool test.
Vertex vectorTo1 = vIntersect - point1OnPlane;
Vertex vectorTo2 = vIntersect - point2OnPlane;
Vertex vectorTo3 = vIntersect - point3OnPlane;
Vertex vectorMidTo1 = midpointOpp1 - point1OnPlane;
Vertex vectorMidTo2 = midpointOpp2 - point2OnPlane;
Vertex vectorMidTo3 = midpointOpp3 - point3OnPlane;
if (vectorTo1.Magnitude() > vectorMidTo1.Magnitude())
{
continue;
}
if (vectorTo2.Magnitude() > vectorMidTo2.Magnitude())
{
continue;
}
if (vectorTo3.Magnitude() > vectorMidTo3.Magnitude())
{
continue;
}
if (intersect.closeness == -1 || t < intersect.closeness)
{
// It's f*****g intersection city man
intersect.point = vIntersect;
intersect.intersected = true;
intersect.normal = planeNormal;
intersect.closeness = t;
}
}
return(intersect);
}
