public bool Intersect(LineSegment l, out Vector2 pt, out Vector2 K)
{
Vector2 P = P1 - P0;
Vector2 S = l.P1 - l.P0;
Matrix2 A = new Matrix2(P.X, -S.X, P.Y, -S.Y);
if (Math.Abs(A.Determinant()) < 1e-10)
{
pt = default(Vector2);
K = default(Vector2);
return(false);
}
K = A.Inverse() * (l.P0 - P0);
if (K.X >= 0 && K.X <= 1 && K.Y >= 0 && K.Y <= 1)
{
pt = P0 + P * K.X;
return(true);
}
else
{
pt = default(Vector2);
return(false);
}
}
public static Circle FromLines(Line oncircle, Line toline, out Vector2 tolinePoint)
{
tolinePoint = default(Vector2);
Vector2 m = (oncircle.P1 - oncircle.P0).Normalize();
Vector2 u = (toline.P1 - toline.P0).Normalize();
if (Math.Abs(m.Cross(u)) < 1e-10)
{
return(Circle.Infinite);
}
Vector2 c = m.Rotate90();
Vector2 t = u.Rotate90();
Vector2 t_c = t - c;
Matrix2 A = new Matrix2(
u.X, t_c.X,
u.Y, t_c.Y);
Vector2 d = oncircle.P0 - toline.P0;
if (Math.Abs(A.Determinant()) < 1e-10)
{
return(Circle.Infinite);
}
Vector2 pvec = A.Inverse() * d;
Vector2 center = oncircle.P0 + pvec.Y * c;
tolinePoint = toline.P0 + pvec.X * u;
return(new Circle(Math.Abs(pvec.Y), center));
}
public void DeterminantIsCorrectFor2x2()
{
// Arrange
var matrix = new Matrix2(3, 5, -2, 3);
// Act
var result = matrix.Determinant();
// Assert
Assert.AreEqual(19, result);
}
public void Determinant_ShouldReturnExpectedValue()
{
// arrange
var sut = new Matrix2(new[, ] {
{ 1f, 5f }, { -3f, 2f }
});
// act
var result = sut.Determinant();
// assert
result.Should().Be(17);
}
