public LinesIntersection2?Intersects(Ray2 ray, out Parallelism parallelism)
{
//http://stackoverflow.com/questions/563198/how-do-you-detect-where-two-line-segments-intersect
var p = Position;
var r = Direction;
var q = ray.Position;
var s = ray.Direction;
// It isn't maths if the variable names make any sense
// ReSharper disable InconsistentNaming
var RxS = r.Cross(s);
var QmP = q - p;
// ReSharper restore InconsistentNaming
if (Math.Abs(RxS - 0) < 0.001)
{
// ReSharper disable InconsistentNaming
var QmPxR = QmP.Cross(r);
// ReSharper restore InconsistentNaming
parallelism = Math.Abs(QmPxR - 0) < 0.001 ? Geometry.Parallelism.Collinear : Geometry.Parallelism.Parallel;
return(null);
}
var t = QmP.Cross(s) / RxS;
var u = QmP.Cross(r) / RxS;
var point = p + (t * r);
parallelism = Geometry.Parallelism.None;
return(new LinesIntersection2(point, t, u));
}
public Parallelism Parallelism(Ray2 ray)
{
//http://stackoverflow.com/questions/563198/how-do-you-detect-where-two-line-segments-intersect
var p = Position;
var r = Direction;
var q = ray.Position;
var s = ray.Direction;
// It isn't maths if the variable names make any sense
// ReSharper disable InconsistentNaming
var RxS = r.Cross(s);
var QmP = q - p;
// ReSharper restore InconsistentNaming
if (Math.Abs(RxS - 0) < 0.001)
{
// ReSharper disable InconsistentNaming
var QmPxR = QmP.Cross(r);
// ReSharper restore InconsistentNaming
return(Math.Abs(QmPxR - 0) < 0.001 ? Geometry.Parallelism.Collinear : Geometry.Parallelism.Parallel);
}
return(Geometry.Parallelism.None);
}
public void AssertThat_RayRayIntersection_FindsParallelLines()
{
Parallelism para;
var i = new Ray2(new Vector2(0, 10), new Vector2(0, 1)).Intersects(new Ray2(new Vector2(20, 5), new Vector2(0, 1)), out para);
Assert.AreEqual(Parallelism.Parallel, para);
Assert.IsFalse(i.HasValue);
}
public void AssertThat_RayRayIntersection_FindsCorrectIntersection()
{
var i = new Ray2(new Vector2(0, 10), new Vector2(0, 1)).Intersects(new Ray2(new Vector2(20, 5), new Vector2(1, 0)));
Assert.IsTrue(i.HasValue);
Assert.AreEqual(-5, i.Value.DistanceAlongA);
Assert.AreEqual(-20, i.Value.DistanceAlongB);
Assert.AreEqual(new Vector2(0, 5), i.Value.Position);
}
public LinesIntersection2?Intersects(Ray2 ray, out Parallelism parallelism)
{
var intersection = LongLine.Intersects(ray, out parallelism);
if (!intersection.HasValue)
{
return(null);
}
if (intersection.Value.DistanceAlongA <= 0 || intersection.Value.DistanceAlongA >= 1)
{
return(null);
}
return(intersection);
}
public void AssertThat_DistanceToPoint_AlwaysEqualsDistanceToClosestPoint()
{
Random r = new Random(1);
for (int i = 0; i < 1000; i++)
{
var start = new Vector2((float)r.NextDouble(), (float)r.NextDouble());
var end = new Vector2((float)r.NextDouble(), (float)r.NextDouble());
var point = new Vector2((float)r.NextDouble(), (float)r.NextDouble());
var ry = new Ray2(start, end - start);
//Check that naieve distance to closest point (literally Distance(CalculateClosestPoint() - Point)
//is the same as the more refined calculation
Assert.AreEqual((ry.ClosestPoint(point) - point).Length(), Math.Abs(ry.DistanceToPoint(point)), 0.001f);
}
}
public void AssertThat_DistanceToPoint_IsSignedDistance_Positive()
{
Ray2 r = new Ray2(new Vector2(1, 1), new Vector2(10, 0));
Assert.AreEqual(9, r.DistanceToPoint(new Vector2(0, 10)));
}
public void AssertThat_DistanceToPoint_IsSignedDistance_Negative()
{
var r = new Ray2(new Vector2(1, 1), new Vector2(20, 0));
Assert.AreEqual(-9, r.DistanceToPoint(new Vector2(0, -8)));
}
/// <summary>
/// Determines whether the specified Ray is equal to the current Ray.
/// </summary>
/// <param name="other">The Ray to compare with the current Ray.</param>
public bool Equals(Ray2 other)
{
return(Position.Equals(other.Position) && Direction.Equals(other.Direction));
}
public LinesIntersection2?Intersects(Ray2 ray)
{
return(Intersects(ray, out var _));
}
public LinesIntersection2? Intersects(Ray2 ray)
{
Parallelism _;
return Intersects(ray, out _);
}
public LinesIntersection2? Intersects(Ray2 ray, out Parallelism parallelism)
{
var intersection = LongLine.Intersects(ray, out parallelism);
if (!intersection.HasValue)
return null;
if (intersection.Value.DistanceAlongA <= 0 || intersection.Value.DistanceAlongA >= 1)
return null;
return intersection;
}
public Parallelism Parallelism(Ray2 ray)
{
//http://stackoverflow.com/questions/563198/how-do-you-detect-where-two-line-segments-intersect
var p = Position;
var r = Direction;
var q = ray.Position;
var s = ray.Direction;
// It isn't maths if the variable names make any sense
// ReSharper disable InconsistentNaming
var RxS = r.Cross(s);
var QmP = q - p;
// ReSharper restore InconsistentNaming
if (Math.Abs(RxS - 0) < 0.001)
{
// ReSharper disable InconsistentNaming
var QmPxR = QmP.Cross(r);
// ReSharper restore InconsistentNaming
return Math.Abs(QmPxR - 0) < 0.001 ? Geometry.Parallelism.Collinear : Geometry.Parallelism.Parallel;
}
return Geometry.Parallelism.None;
}
public LinesIntersection2? Intersects(Ray2 ray, out Parallelism parallelism)
{
//http://stackoverflow.com/questions/563198/how-do-you-detect-where-two-line-segments-intersect
var p = Position;
var r = Direction;
var q = ray.Position;
var s = ray.Direction;
// It isn't maths if the variable names make any sense
// ReSharper disable InconsistentNaming
var RxS = r.Cross(s);
var QmP = q - p;
// ReSharper restore InconsistentNaming
if (Math.Abs(RxS - 0) < 0.001)
{
// ReSharper disable InconsistentNaming
var QmPxR = QmP.Cross(r);
// ReSharper restore InconsistentNaming
parallelism = Math.Abs(QmPxR - 0) < 0.001 ? Geometry.Parallelism.Collinear : Geometry.Parallelism.Parallel;
return null;
}
var t = QmP.Cross(s) / RxS;
var u = QmP.Cross(r) / RxS;
var point = p + (t * r);
parallelism = Geometry.Parallelism.None;
return new LinesIntersection2(point, t, u);
}
/// <summary>
/// Determines whether the specified Ray is equal to the current Ray.
/// </summary>
/// <param name="other">The Ray to compare with the current Ray.</param>
public bool Equals(Ray2 other)
{
return Position.Equals(other.Position) && Direction.Equals(other.Direction);
}
