public void Constructor_from_a_vector_sets_XYZ_to_the_vector_values_and_W_to_0()
{
var vector3 = new Vector3(1, 2, 3);
var quaternion = new Quaternion(vector3);
quaternion.W.ShouldEqual(0);
quaternion.X.ShouldEqual(vector3.X);
quaternion.Y.ShouldEqual(vector3.Y);
quaternion.Z.ShouldEqual(vector3.Z);
}
public void Concatenation_with_the_multiply_operator()
{
var quat1 = new Quaternion(Vector3.ZAxis, Constants.HALF_PI);
var quat2 = new Quaternion(Vector3.XAxis, Constants.HALF_PI);
var concatenated = quat2 * quat1;
concatenated.X.ShouldEqual(0.2580212f, Constants.DELTA);
concatenated.Y.ShouldEqual(-0.2580212f, Constants.DELTA);
concatenated.Z.ShouldEqual(0.2580212f, Constants.DELTA);
concatenated.W.ShouldEqual(0.9689124f, Constants.DELTA);
}
public void ToAxisAngle()
{
Vector3 rotationAxis = Vector3.ZAxis;
var angle = Constants.HALF_PI;
var quaternion = new Quaternion(rotationAxis, angle);
Vector4 axisAngle = quaternion.ToAxisAngle();
axisAngle.X.ShouldEqual(rotationAxis.X);
axisAngle.Y.ShouldEqual(rotationAxis.Y);
axisAngle.Z.ShouldEqual(rotationAxis.Z);
axisAngle.W.ShouldEqual(angle);
}
public void Constructor_with_two_vectors_creates_rotation_between_the_two()
{
Vector3 sourcePosition = Vector3.XAxis;
Vector3 destinationPosition = Vector3.YAxis;
var quaternion = new Quaternion(sourcePosition, destinationPosition);
var halfSquarerootOfTwo = 0.5f * Functions.Sqrt(2);
quaternion.W.ShouldEqual(halfSquarerootOfTwo);
quaternion.X.ShouldEqual(0);
quaternion.Y.ShouldEqual(0);
quaternion.Z.ShouldEqual(halfSquarerootOfTwo);
}
public void Constructor_with_rotation_axis_and_angle()
{
Vector3 rotationAxis = Vector3.ZAxis;
var angle = Constants.HALF_PI;
var quaternion = new Quaternion(rotationAxis, angle);
var halfSquarerootOfTwo = 0.5f * Functions.Sqrt(2);
quaternion.W.ShouldEqual(halfSquarerootOfTwo);
quaternion.X.ShouldEqual(0);
quaternion.Y.ShouldEqual(0);
quaternion.Z.ShouldEqual(halfSquarerootOfTwo);
}
public void ToMatrix()
{
Vector3 rotationAxis = Vector3.ZAxis;
var angle = Constants.HALF_PI;
var quaternion = new Quaternion(rotationAxis, angle);
Matrix matrix = quaternion.ToMatrix();
var expected = new Matrix(
Functions.Cos(angle), -Functions.Sin(angle), 0, 0,
Functions.Sin(angle), Functions.Cos(angle), 0, 0,
0, 0, 1, 0,
0, 0, 0, 1);
matrix.ShouldEqual(expected);
}