public void Test_S1ChordAngle_Trigonometry()
{
const int kIters = 20;
for (int iter = 0; iter <= kIters; ++iter)
{
double radians = Math.PI * iter / kIters;
S1ChordAngle angle = new(S1Angle.FromRadians(radians));
Assert2.Near(Math.Sin(radians), angle.Sin(), S2.DoubleError);
Assert2.Near(Math.Cos(radians), angle.Cos(), S2.DoubleError);
// Since the tan(x) is unbounded near Pi/4, we map the result back to an
// angle before comparing. (The assertion is that the result is equal to
// the tangent of a nearby angle.)
Assert2.Near(Math.Atan(Math.Tan(radians)), Math.Atan(angle.Tan()), S2.DoubleError);
}
// Unlike S1Angle, S1ChordAngle can represent 90 and 180 degrees exactly.
S1ChordAngle angle90 = S1ChordAngle.FromLength2(2);
S1ChordAngle angle180 = S1ChordAngle.FromLength2(4);
Assert.Equal(1, angle90.Sin());
Assert.Equal(0, angle90.Cos());
Assert.Equal(double.PositiveInfinity, angle90.Tan());
Assert.Equal(0, angle180.Sin());
Assert.Equal(-1, angle180.Cos());
Assert.Equal(0, angle180.Tan());
}
public void Test_S2_UpdateMinInteriorDistanceRejectionTestIsConservative()
{
// This test checks several representative cases where previously
// UpdateMinInteriorDistance was failing to update the distance because a
// rejection test was not being done conservatively.
//
// Note that all of the edges AB in this test are nearly antipodal.
{
S2Point x = new(1, -4.6547732744037044e-11, -5.6374428459823598e-89);
S2Point a = new(1, -8.9031850507928352e-11, 0);
S2Point b = new(-0.99999999999996347, 2.7030110029169596e-07,
1.555092348806121e-99);
var min_dist = S1ChordAngle.FromLength2(6.3897233584120815e-26);
Assert.True(S2.UpdateMinInteriorDistance(x, a, b, ref min_dist));
}
{
S2Point x = new(1, -4.7617930898495072e-13, 0);
S2Point a = new(-1, -1.6065916409055676e-10, 0);
S2Point b = new(1, 0, 9.9964883247706732e-35);
var min_dist = S1ChordAngle.FromLength2(6.3897233584120815e-26);
Assert.True(S2.UpdateMinInteriorDistance(x, a, b, ref min_dist));
}
{
S2Point x = new(1, 0, 0);
S2Point a = new(1, -8.4965026896454536e-11, 0);
S2Point b = new(-0.99999999999966138, 8.2297529603339328e-07,
9.6070344113320997e-21);
var min_dist = S1ChordAngle.FromLength2(6.3897233584120815e-26);
Assert.True(S2.UpdateMinInteriorDistance(x, a, b, ref min_dist));
}
}
public void Test_S1ChordAngle_FromLength2()
{
Assert.Equal(0, S1ChordAngle.FromLength2(0).Degrees());
Assert2.DoubleEqual(60, S1ChordAngle.FromLength2(1).Degrees());
Assert2.DoubleEqual(90, S1ChordAngle.FromLength2(2).Degrees());
Assert.Equal(180, S1ChordAngle.FromLength2(4).Degrees());
Assert.Equal(180, S1ChordAngle.FromLength2(5).Degrees());
}
public void Test_S1ChordAngle_PlusError()
{
Assert.Equal(S1ChordAngle.Negative, S1ChordAngle.Negative.PlusError(5));
Assert.Equal(S1ChordAngle.Infinity, S1ChordAngle.Infinity.PlusError(-5));
Assert.Equal(S1ChordAngle.Straight, S1ChordAngle.Straight.PlusError(5));
Assert.Equal(S1ChordAngle.Zero, S1ChordAngle.Zero.PlusError(-5));
Assert.Equal(S1ChordAngle.FromLength2(1.25),
S1ChordAngle.FromLength2(1).PlusError(0.25));
Assert.Equal(S1ChordAngle.FromLength2(0.75),
S1ChordAngle.FromLength2(1).PlusError(-0.25));
}
public void Test_S1ChordAngle_Negative()
{
Assert.True(S1ChordAngle.Negative < S1ChordAngle.Zero);
Assert.True(S1ChordAngle.Negative == S1ChordAngle.FromLength2(-1));
Assert.True(S1ChordAngle.Negative.ToAngle() < S1Angle.Zero);
}