/// <summary>
/// Slicing function used for earthquake puzzles.
/// c should be geodesic (orthogonal to the disk boundary).
/// </summary>
public static void SlicePolygonWithHyperbolicGeodesic(Polygon p, CircleNE c, double thickness, out List <Polygon> output)
{
Geometry g = Geometry.Hyperbolic;
Segment seg = null;
if (c.IsLine)
{
Vector3D p1, p2;
Euclidean2D.IntersectionLineCircle(c.P1, c.P2, new Circle(), out p1, out p2);
seg = Segment.Line(p1, p2);
}
else
{
// Setup the two slicing circles.
// These are cuts equidistant from the passed in geodesic.
Vector3D closestToOrigin = H3Models.Ball.ClosestToOrigin(new Circle3D()
{
Center = c.Center, Radius = c.Radius, Normal = new Vector3D(0, 0, 1)
});
Vector3D p1, p2;
Euclidean2D.IntersectionCircleCircle(c, new Circle(), out p1, out p2);
seg = Segment.Arc(p1, closestToOrigin, p2);
}
Circle c1 = H3Models.Ball.EquidistantOffset(g, seg, thickness / 2);
Circle c2 = H3Models.Ball.EquidistantOffset(g, seg, -thickness / 2);
CircleNE c1NE = c.Clone(), c2NE = c.Clone();
c1NE.Center = c1.Center; c2NE.Center = c2.Center;
c1NE.Radius = c1.Radius; c2NE.Radius = c2.Radius;
SlicePolygonHelper(p, c1NE, c2NE, out output);
}
/// <summary>
/// Reflect a point in us.
/// ZZZ - This method is confusing in that it is opposite the above (we aren't reflecting ourselves here).
/// </summary>
/// <param name="p"></param>
public Vector3D ReflectPoint(Vector3D p)
{
if (this.IsLine)
{
return(Euclidean2D.ReflectPointInLine(p, P1, P2));
}
else
{
// Handle infinities.
Vector3D infinityVector = Infinity.InfinityVector;
if (p.Compare(Center))
{
return(infinityVector);
}
if (p == infinityVector)
{
return(Center);
}
Vector3D v = p - Center;
double d = v.Abs();
v.Normalize();
return(Center + v * (Radius * Radius / d));
}
}
/// <summary>
/// Checks to see if two points are ordered on this segment, that is:
/// P1 -> test1 -> test2 -> P2 returns true.
/// P1 -> test2 -> test1 -> P2 returns false;
/// Also returns false if test1 or test2 are equal, not on the segment, or are an endpoint.
/// </summary>
/// <param name="p1"></param>
/// <param name="p2"></param>
/// <returns></returns>
public bool Ordered(Vector3D test1, Vector3D test2)
{
if (test1.Compare(test2))
{
Debug.Assert(false);
return(false);
}
if (!IsPointOn(test1) || !IsPointOn(test2))
{
Debug.Assert(false);
return(false);
}
if (test1.Compare(P1) || test1.Compare(P2) ||
test2.Compare(P1) || test2.Compare(P2))
{
return(false);
}
if (SegmentType.Arc == Type)
{
Vector3D t1 = P1 - Center;
Vector3D t2 = test1 - Center;
Vector3D t3 = test2 - Center;
double a1 = Clockwise ? Euclidean2D.AngleToClock(t1, t2) : Euclidean2D.AngleToCounterClock(t1, t2);
double a2 = Clockwise ? Euclidean2D.AngleToClock(t1, t3) : Euclidean2D.AngleToCounterClock(t1, t3);
return(a1 < a2);
}
else
{
double d1 = (test1 - P1).MagSquared();
double d2 = (test2 - P1).MagSquared();
return(d1 < d2);
}
}
public static Vector3D SpiralToIsometric(Vector3D v, int p, int m, int n)
{
Complex vc = v.ToComplex();
v = new Vector3D(Math.Log(vc.Magnitude), vc.Phase);
Vector3D e1 = new Vector3D(0, 1);
Vector3D e2;
switch (p)
{
case 3:
e2 = new Vector3D(); break;
case 4:
e2 = new Vector3D(); break;
case 6:
e2 = new Vector3D(); break;
default:
throw new System.ArgumentException();
}
double scale = Math.Sqrt(m * m + n * n);
double a = Euclidean2D.AngleToClock(new Vector3D(0, 1), new Vector3D(m, n));
v.RotateXY(a); // Rotate
v *= scale; // Scale
v *= Math.Sqrt(2) * Geometry2D.EuclideanHypotenuse / (2 * Math.PI);
v.RotateXY(Math.PI / 4);
return(v);
}
/// <summary>
/// Construct a circle from 3 points
/// </summary>
/// <returns>false if the construction failed (if we are a line).</returns>
public bool From3Points(Vector3D p1, Vector3D p2, Vector3D p3)
{
Reset();
// Check for any infinite points, in which case we are a line.
// I'm not sure these checks are smart, since our IsInfinite check is so inclusive,
// but Big Chop puzzle doesn't work if we don't do this.
// ZZZ - Still, I need to think on this more.
if (Infinity.IsInfinite(p1))
{
this.From2Points(p2, p3);
return(false);
}
else if (Infinity.IsInfinite(p2))
{
this.From2Points(p1, p3);
return(false);
}
else if (Infinity.IsInfinite(p3))
{
this.From2Points(p1, p2);
return(false);
}
/* Some links
* http://mathforum.org/library/drmath/view/54323.html
* http://delphiforfun.org/Programs/Math_Topics/circle_from_3_points.htm
* There is lots of info out there about solving via equations,
* but as with other code in this project, I wanted to use geometrical constructions. */
// Midpoints.
Vector3D m1 = (p1 + p2) / 2;
Vector3D m2 = (p1 + p3) / 2;
// Perpendicular bisectors.
Vector3D b1 = (p2 - p1) / 2;
Vector3D b2 = (p3 - p1) / 2;
b1.Normalize();
b2.Normalize();
b1.Rotate90();
b2.Rotate90();
Vector3D newCenter;
int found = Euclidean2D.IntersectionLineLine(m1, m1 + b1, m2, m2 + b2, out newCenter);
Center = newCenter;
if (0 == found)
{
// The points are collinear, so we are a line.
From2Points(p1, p2);
return(false);
}
Radius = (p1 - Center).Abs();
Debug.Assert(Tolerance.Equal(Radius, (p2 - Center).Abs()));
Debug.Assert(Tolerance.Equal(Radius, (p3 - Center).Abs()));
return(true);
}
public bool IsPointOn(Vector3D test)
{
if (this.IsLine)
{
return(Tolerance.Zero(Euclidean2D.DistancePointLine(test, P1, P2)));
}
return(Tolerance.Equal((test - Center).Abs(), Radius));
}
public Vector3D ReflectPoint(Vector3D input)
{
if (SegmentType.Arc == Type)
{
Circle c = this.Circle;
return(c.ReflectPoint(input));
}
else
{
return(Euclidean2D.ReflectPointInLine(input, P1, P2));
}
}
public bool Intersects(Segment s)
{
Vector3D i1 = Vector3D.DneVector(), i2 = Vector3D.DneVector();
int numInt = 0;
if (SegmentType.Arc == Type)
{
if (SegmentType.Arc == s.Type)
{
numInt = Euclidean2D.IntersectionCircleCircle(Circle, s.Circle, out i1, out i2);
}
else
{
numInt = Euclidean2D.IntersectionLineCircle(P1, P2, s.Circle, out i1, out i2);
}
}
else
{
if (SegmentType.Arc == s.Type)
{
numInt = Euclidean2D.IntersectionLineCircle(s.P1, s.P2, Circle, out i1, out i2);
}
else
{
numInt = Euclidean2D.IntersectionLineLine(P1, P2, s.P1, s.P2, out i1);
}
}
// -1 can denote conincident segments (I'm not consistent in the impls above :/),
// and we are not going to include those for now.
if (numInt <= 0)
{
return(false);
}
if (numInt > 0)
{
if (IsPointOn(i1) && s.IsPointOn(i1))
{
return(true);
}
}
if (numInt > 1)
{
if (IsPointOn(i2) && s.IsPointOn(i2))
{
return(true);
}
}
return(false);
}
private static bool PointOnArcSegment(Vector3D p, Segment seg)
{
double maxAngle = seg.Angle;
Vector3D v1 = seg.P1 - seg.Center;
Vector3D v2 = p - seg.Center;
Debug.Assert(Tolerance.Equal(v1.Abs(), v2.Abs()));
double angle = seg.Clockwise ?
Euclidean2D.AngleToClock(v1, v2) :
Euclidean2D.AngleToCounterClock(v1, v2);
return(Tolerance.LessThanOrEqual(angle, maxAngle));
}
// Get the intersection points with a segment.
// Returns null if the segment is an arc coincident with the circle (infinite number of intersection points).
public Vector3D[] GetIntersectionPoints(Segment segment)
{
Vector3D p1, p2;
int result;
// Are we a line?
if (this.IsLine)
{
if (SegmentType.Arc == segment.Type)
{
Circle tempCircle = segment.Circle;
result = Euclidean2D.IntersectionLineCircle(this.P1, this.P2, tempCircle, out p1, out p2);
}
else
{
result = Euclidean2D.IntersectionLineLine(this.P1, this.P2, segment.P1, segment.P2, out p1);
p2 = Vector3D.DneVector();
}
}
else
{
if (SegmentType.Arc == segment.Type)
{
Circle tempCircle = segment.Circle;
result = Euclidean2D.IntersectionCircleCircle(tempCircle, this, out p1, out p2);
}
else
{
result = Euclidean2D.IntersectionLineCircle(segment.P1, segment.P2, this, out p1, out p2);
}
}
if (-1 == result)
{
return(null);
}
List <Vector3D> ret = new List <Vector3D>();
if (result >= 1 && segment.IsPointOn(p1))
{
ret.Add(p1);
}
if (result >= 2 && segment.IsPointOn(p2))
{
ret.Add(p2);
}
return(ret.ToArray());
}
private static double StereoToEquidistant(double dist)
{
if (Infinity.IsInfinite(dist))
{
return(1);
}
double dot = dist * dist; // X^2 + Y^2 + Z^2
double w = (dot - 1) / (dot + 1);
double x = Math.Sqrt(1 - w * w);
double r = Euclidean2D.AngleToCounterClock(new Vector3D(0, -1), new Vector3D(x, w));
return(r / Math.PI);
}
/// <summary>
/// Apply a transform to us.
/// </summary>
private void TransformInternal <T>(T transform) where T : ITransform
{
// NOTES:
// Arcs can go to lines, and lines to arcs.
// Rotations may reverse arc directions as well.
// Arc centers can't be transformed directly.
// NOTE: We must calc this before altering the endpoints.
Vector3D mid = Midpoint;
if (Infinity.IsInfinite(mid))
{
mid = Infinity.IsInfinite(P1) ? P2 * Infinity.FiniteScale : P1 * Infinity.FiniteScale;
}
P1 = transform.Apply(P1);
P2 = transform.Apply(P2);
mid = transform.Apply(mid);
// Can we make a circle out of the transformed points?
Circle temp = new Circle();
if (!Infinity.IsInfinite(P1) && !Infinity.IsInfinite(P2) && !Infinity.IsInfinite(mid) &&
temp.From3Points(P1, mid, P2))
{
Type = SegmentType.Arc;
Center = temp.Center;
// Work out the orientation of the arc.
Vector3D t1 = P1 - Center;
Vector3D t2 = mid - Center;
Vector3D t3 = P2 - Center;
double a1 = Euclidean2D.AngleToCounterClock(t2, t1);
double a2 = Euclidean2D.AngleToCounterClock(t3, t1);
Clockwise = a2 > a1;
}
else
{
// The circle construction fails if the points
// are colinear (if the arc has been transformed into a line).
Type = SegmentType.Line;
// XXX - need to do something about this.
// Turn into 2 segments?
//if( isInfinite( mid ) )
// Actually the check should just be whether mid is between p1 and p2.
}
}
/// <summary>
/// Maps a point in a rhombus to a point in the unit square, via a simple affine transformation.
/// b1 and b2 are the two basis vectors of the rhombus.
/// Does not currently check the input point.
/// </summary>
public static Vector3D MapRhombusToUnitSquare(Vector3D b1, Vector3D b2, Vector3D v)
{
double a = Euclidean2D.AngleToCounterClock(b1, new Vector3D(1, 0));
v.RotateXY(a);
b1.RotateXY(a);
b2.RotateXY(a);
// Shear
v.X -= b2.X * (v.Y / b2.Y);
// Scale x and y.
v.X /= b1.X;
v.Y /= b2.Y;
return(v);
}
/// <summary>
/// Normalize so P1 is closest point to origin,
/// and direction vector is of unit length.
/// </summary>
public void NormalizeLine()
{
if (!this.IsLine)
{
return;
}
Vector3D d = P2 - P1;
d.Normalize();
P1 = Euclidean2D.ProjectOntoLine(new Vector3D(), P1, P2);
// ZZZ - Could probably do something more robust to choose proper direction.
if (Tolerance.GreaterThanOrEqual(Euclidean2D.AngleToClock(d, new Vector3D(1, 0)), Math.PI))
{
d *= -1;
}
P2 = P1 + d;
}
/// <summary>
/// Checks to see if a point is inside us, in a non-Euclidean sense.
/// This works if we are inverted, and even if we are a line!
/// (if we are a line, half of the plane is still "inside").
/// </summary>
public bool IsPointInsideNE(Vector3D testPoint)
{
if (this.IsLine)
{
// We are inside if the test point is on the same side
// as the non-Euclidean center.
return(Euclidean2D.SameSideOfLine(P1, P2, testPoint, CenterNE));
}
else
{
// Whether we are inside in the Euclidean sense.
bool pointInside = false;
if (!Infinity.IsInfinite(testPoint))
{
pointInside = this.IsPointInside(testPoint);
}
// And in the Non-Euclidean sense.
bool inverted = this.Inverted;
return((!inverted && pointInside) ||
(inverted && !pointInside));
}
}
/// <summary>
/// Returns the 6 simplex edges in the UHS model.
/// </summary>
public static H3.Cell.Edge[] SimplexEdgesUHS(int p, int q, int r)
{
// Only implemented for honeycombs with hyperideal cells right now.
if (!(Geometry2D.GetGeometry(p, q) == Geometry.Hyperbolic))
{
throw new System.NotImplementedException();
}
Sphere[] simplex = SimplexCalcs.Mirrors(p, q, r, moveToBall: false);
Circle[] circles = simplex.Select(s => H3Models.UHS.IdealCircle(s)).ToArray();
Vector3D[] defPoints = new Vector3D[6];
Vector3D dummy;
Euclidean2D.IntersectionLineCircle(circles[1].P1, circles[1].P2, circles[0], out defPoints[0], out dummy);
Euclidean2D.IntersectionLineCircle(circles[2].P1, circles[2].P2, circles[0], out defPoints[1], out dummy);
Euclidean2D.IntersectionLineCircle(circles[1].P1, circles[1].P2, circles[3], out defPoints[2], out dummy);
Euclidean2D.IntersectionLineCircle(circles[2].P1, circles[2].P2, circles[3], out defPoints[3], out dummy);
Circle3D c = simplex[0].Intersection(simplex[3]);
Vector3D normal = c.Normal;
normal.RotateXY(Math.PI / 2);
Vector3D intersection;
double height, off;
Euclidean2D.IntersectionLineLine(c.Center, c.Center + normal, circles[1].P1, circles[1].P2, out intersection);
off = (intersection - c.Center).Abs();
height = Math.Sqrt(c.Radius * c.Radius - off * off);
intersection.Z = height;
defPoints[4] = intersection;
Euclidean2D.IntersectionLineLine(c.Center, c.Center + normal, circles[2].P1, circles[2].P2, out intersection);
off = (intersection - c.Center).Abs();
height = Math.Sqrt(c.Radius * c.Radius - off * off);
intersection.Z = height;
defPoints[5] = intersection;
// Hyperideal vertex too?
bool order = false;
H3.Cell.Edge[] edges = null;
if (Geometry2D.GetGeometry(q, r) == Geometry.Hyperbolic)
{
edges = new H3.Cell.Edge[]
{
new H3.Cell.Edge(new Vector3D(), new Vector3D(0, 0, 10)),
new H3.Cell.Edge(defPoints[4], defPoints[5], order),
new H3.Cell.Edge(defPoints[0], defPoints[4], order),
new H3.Cell.Edge(defPoints[1], defPoints[5], order),
new H3.Cell.Edge(defPoints[2], defPoints[4], order),
new H3.Cell.Edge(defPoints[3], defPoints[5], order),
};
}
else
{
Vector3D vPointUHS = H3Models.BallToUHS(VertexPointBall(p, q, r));
defPoints[0] = defPoints[1] = vPointUHS;
edges = new H3.Cell.Edge[]
{
new H3.Cell.Edge(vPointUHS, new Vector3D(0, 0, 10)),
new H3.Cell.Edge(defPoints[4], defPoints[5], order),
new H3.Cell.Edge(defPoints[0], defPoints[4], order),
new H3.Cell.Edge(defPoints[1], defPoints[5], order),
new H3.Cell.Edge(defPoints[2], defPoints[4], order),
new H3.Cell.Edge(defPoints[3], defPoints[5], order),
};
}
return(edges);
}
/// <summary>
/// Reflects a point in a line defined by two points.
/// </summary>
public static Vector3D ReflectPointInLine(Vector3D input, Vector3D p1, Vector3D p2)
{
Vector3D p = Euclidean2D.ProjectOntoLine(input, p1, p2);
return(input + (p - input) * 2);
}