public void Cross_product_is_anticommutative()
{
var a = new Vector(1, 2, 3);
var b = new Vector(6, 4, 5);
Assert.Equal(Vector.CrossProduct(a, b), -Vector.CrossProduct(b, a));
}
public void The_operation_is_commutative()
{
var a = new Vector(1, 2, 3);
var b = new Vector(6, -7, -8);
Assert.Equal(Vector.DotProduct(a, b), Vector.DotProduct(b, a));
}
public void The_operation_is_commutative()
{
var vector = new Vector(3, -49, 17);
var scalar = 14.7f;
Assert.Equal(vector * scalar, scalar * vector);
}
public void The_operation_is_commutative()
{
var a = new Vector(18, 4, -91);
var b = new Vector(63, 86, -12);
Assert.Equal(a + b, b + a);
}
public void The_result_is_a_vector_whos_dot_product_with_the_original_vector_equals_the_original_vectors_length()
{
var x = new Vector(10, 4.7f, -13);
Assert.Equal(
x.Length,
Vector.DotProduct(x.ToUnitVector(), x), EpsilonComparer.DoubleComparer);
}
public Ray(Point origin, Vector direction)
{
if (!direction.IsUnit) {
throw new ArgumentException("Rays can only be constructed with unit-vector directions.");
}
Origin = origin;
Direction = direction;
}
public void The_resulting_vector_has_a_dot_product_of_zero_with_both_input_vectors()
{
var a = new Vector(2, 3, 4);
var b = new Vector(4, 5, 6);
var cross = Vector.CrossProduct(a, b);
Assert.Equal(0f, Vector.DotProduct(a, cross));
Assert.Equal(0f, Vector.DotProduct(cross, b));
}
public void A_translation_matrix_should_result_in_the_same_vector()
{
var vector = new Vector(1, 2, 3);
var matrix = new Matrix(
1, 0, 0, 1,
0, 1, 0, 2,
0, 0, 1, 3,
0, 0, 0, 1);
Assert.Equal(vector, matrix * vector);
}
/// <summary>
/// Creates a matrix that represents a rotation of <paramref name="angle"/> radians about <paramref name="axis"/>.
/// </summary>
/// <remarks>
/// We use the same coordinate system as OpenGL (right-handed), and we use their matrix rotation specs as a spec for our rotations.
/// <see cref="http://opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/rotate.html"/>
/// </remarks>
public static Matrix Rotation(Vector axis, double angle)
{
axis = axis.ToUnitVector();
var x = axis.X;
var y = axis.Y;
var z = axis.Z;
var sin = System.Math.Sin(angle);
var cos = System.Math.Cos(angle);
return new Matrix(
x * x * (1 - cos) + cos, x * y * (1 - cos) - (z * sin), x * z * (1 - cos) + y * sin, 0,
y * x * (1 - cos) + z * sin, y * y * (1 - cos) + cos, y * z * (1 - cos) - x * sin, 0,
x * z * (1 - cos) - y * sin, y * z * (1 - cos) + x * sin, z * z * (1 - cos) + cos, 0,
0, 0, 0, 0
);
}
public AxisAlignedBoundingBox GetBoundingBox()
{
var vec = new Vector(Radius, Radius, Radius);
return new AxisAlignedBoundingBox(Position - vec, Position + vec);
}
public void Equals_the_square_root_of_the_SquaredLength_property()
{
var a = new Vector(43, 29, -14);
Assert.Equal(System.Math.Sqrt(a.SquaredLength), a.Length);
}
private static Vector Rotate90Degrees(Vector vectorToRotate, Vector rotationAxis)
{
var transformation = Matrix.Rotation(rotationAxis, 90d.ToRadians());
return transformation * vectorToRotate;
}
public static Matrix Rotate(this Matrix matrix, Vector axis, double angle)
{
return matrix * Matrix.Rotation(axis, angle);
}
public static Matrix PerspectiveProjection(Vector position, Vector view, Vector up, double fieldOfView, double aspectRatio)
{
throw new NotImplementedException();
}
public void The_result_is_equal_to_the_SquaredLength_property_when_a_vector_is_dotted_with_itself()
{
var vector = new Vector(82408, 42, 1337);
Assert.Equal(vector.SquaredLength, Vector.DotProduct(vector, vector));
}
public void The_identity_matrix_should_result_in_the_same_vector()
{
var vector = new Vector(1, 2, 3);
Assert.Equal(vector, Matrix.Identity * vector);
}
