public void TestVector3ExpDecay()
{
Vector3 from = new Vector3(50.0f, 150.0f, 250.0f);
Vector3 to = new Vector3(150.0f, 250.0f, 350.0f);
// Validates the Vector3 overload of InterpolationUtilities::ExpDecay, which lerps between the from value
// toward the to value in an exponential fashion.
Assert.That(InterpolationUtilities.ExpDecay(from, to, 0.0f /*hLife*/, 5.0f /*dTime*/),
Is.EqualTo(new Vector3(150.0f, 250.0f, 350.0f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 1.0f /*hLife*/, 1.0f /*dTime*/),
Is.EqualTo(new Vector3(100.0f, 200.0f, 300.0f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 2.0f /*dTime*/),
Is.EqualTo(new Vector3(100.0f, 200.0f, 300.0f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 4.0f /*dTime*/),
Is.EqualTo(new Vector3(125.0f, 225.0f, 325.0f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 6.0f /*dTime*/),
Is.EqualTo(new Vector3(137.5f, 237.5f, 337.5f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 20.0f /*dTime*/),
Is.EqualTo(new Vector3(149.90234f, 249.90234f, 349.90234f)));
}
public void TestFloatExpDecay()
{
// Validates the float overload of InterpolationUtilities::ExpDecay, which lerps between the from value
// toward the to value in an exponential fashion.
Assert.That(InterpolationUtilities.ExpDecay(50.0f /*from*/, 150.0f /*to*/, 0.0f /*hLife*/, 5.0f /*dTime*/), Is.EqualTo(150f));
Assert.That(InterpolationUtilities.ExpDecay(50.0f /*from*/, 150.0f /*to*/, 1.0f /*hLife*/, 1.0f /*dTime*/), Is.EqualTo(100.0f));
Assert.That(InterpolationUtilities.ExpDecay(50.0f /*from*/, 150.0f /*to*/, 2.0f /*hLife*/, 2.0f /*dTime*/), Is.EqualTo(100.0f));
Assert.That(InterpolationUtilities.ExpDecay(50.0f /*from*/, 150.0f /*to*/, 2.0f /*hLife*/, 4.0f /*dTime*/), Is.EqualTo(125.0f));
Assert.That(InterpolationUtilities.ExpDecay(50.0f /*from*/, 150.0f /*to*/, 2.0f /*hLife*/, 6.0f /*dTime*/), Is.EqualTo(137.5f));
Assert.That(InterpolationUtilities.ExpDecay(50.0f /*from*/, 150.0f /*to*/, 2.0f /*hLife*/, 20.0f /*dTime*/), Is.EqualTo(149.90234f));
}
public void TestExpCoefficient()
{
// Passing a half life value of 0 always returns a value of 1 (this is an 'invalid' calling convention).
Assert.That(InterpolationUtilities.ExpCoefficient(0.0f /*hLife*/, 10.0f /*dTime*/), Is.EqualTo(1.0f));
Assert.That(InterpolationUtilities.ExpCoefficient(0.0f /*hLife*/, 0.0f /*dTime*/), Is.EqualTo(1.0f));
// Passing a valid half life and delta time should result in increasingly higher numbers according to
// the formula (1-.5^(half life / delta time))
Assert.That(InterpolationUtilities.ExpCoefficient(2.0f /*hLife*/, 2.0f /*dTime*/), Is.EqualTo(0.5f));
Assert.That(InterpolationUtilities.ExpCoefficient(2.0f /*hLife*/, 4.0f /*dTime*/), Is.EqualTo(0.75f));
Assert.That(InterpolationUtilities.ExpCoefficient(2.0f /*hLife*/, 6.0f /*dTime*/), Is.EqualTo(0.875f));
}
public void TestColorExpDecay()
{
Color from = new Color(0.0f, 0.0f, 1.0f);
Color to = new Color(1.0f, 0.0f, 0.0f);
// Validates the Color overload of InterpolationUtilities::ExpDecay, which lerps between the from value
// toward the to value in an exponential fashion.
Assert.That(InterpolationUtilities.ExpDecay(from, to, 0.0f /*hLife*/, 5.0f /*dTime*/),
Is.EqualTo(new Color(1.0f, 0.0f, 0.0f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 1.0f /*hLife*/, 1.0f /*dTime*/),
Is.EqualTo(new Color(0.5f, 0.0f, 0.5f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 2.0f /*dTime*/),
Is.EqualTo(new Color(0.5f, 0.0f, 0.5f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 4.0f /*dTime*/),
Is.EqualTo(new Color(0.75f, 0.0f, 0.25f)));
Assert.That(InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 6.0f /*dTime*/),
Is.EqualTo(new Color(0.875f, 0.0f, 0.125f)));
}
public void TestQuaternionExpDecay()
{
// Validates the Quaternion overload of InterpolationUtilities::ExpDecay, which lerps between the from value
// toward the to value in an exponential fashion.
// Note that Quaternions are a bit funky in that they are using spherical lerps, which means the lerp occurs
// on the surface of a sphere (instead of a linear lerp between points)
Quaternion from = Quaternion.Euler(new Vector3(0, 0, 0));
Quaternion to = Quaternion.Euler(new Vector3(0, 45, 0));
Assert.IsTrue(InterpolationUtilities.ExpDecay(from, to, 0.0f /*hLife*/, 5.0f /*dTime*/) == to);
// This test ultimately converts the lerped values into rotation effects on the forward vector, to show
// that this is properly lerping in a more human-readable fashion (i.e. reading unit vector directions, instead
// of quaternions)
Vector3 result = InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 2.0f /*dTime*/) * Vector3.forward;
Assert.IsTrue(
AreEqual(
InterpolationUtilities.ExpDecay(from, to, 1.0f /*hLife*/, 1.0f /*dTime*/) * Vector3.forward,
new Vector3(0.3826835f, 0.0f, 0.9238795f)));
Assert.IsTrue(
AreEqual(
InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 2.0f /*dTime*/) * Vector3.forward,
new Vector3(0.3826835f, 0.0f, 0.9238795f)));
Assert.IsTrue(
AreEqual(
InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 4.0f /*dTime*/) * Vector3.forward,
new Vector3(0.5555702f, 0.0f, 0.8314696f)));
Assert.IsTrue(
AreEqual(
InterpolationUtilities.ExpDecay(from, to, 2.0f /*hLife*/, 6.0f /*dTime*/) * Vector3.forward,
new Vector3(0.6343933f, 0.0f, 0.7730104f)));
}
