/// <summary>
/// Test if this AxisAngle is approximately equal to another.
/// </summary>
/// <param name="other"></param>
/// <returns></returns>
public bool IsSimilar(AxisAngle other)
{
return(Math.Abs(this.Axis.X - other.Axis.X) < EPSILON2 &&
Math.Abs(this.Axis.Y - other.Axis.Y) < EPSILON2 &&
Math.Abs(this.Axis.Z - other.Axis.Z) < EPSILON2 &&
Math.Abs(this.Angle - other.Angle) < EPSILON2);
}
/// <summary>
/// Is this rotation equivalent to a given one?
/// Equivalence is defined as rotations around vectors sharing the same axis (including opposite directions)
/// and an angle with the same modulated equivalence. This in turn means the same spatial orientation after transformation.
/// For example, the following rotations are equivalent:
/// [0, 0, 1, 315]
/// [0, 0, 1, 675] (one additional turn, same angle)
/// [0, 0, 1, -45] (negative rotation, same angle)
/// [0, 0, -1, 45] (flipped axis, same angle)
/// [0, 0, 10, 315] (same axis and angle, longer vector. note non-unit vectors are not allowed in this AA representation)
///
/// Also, these are equivalent:
/// [0, 0, 0, 0]
/// [0, 0, 1, 720]
/// </summary>
/// <param name="other"></param>
/// <returns></returns>
public bool IsEquivalent(AxisAngle other)
{
// Sanity checks
if (this.IsZero())
{
return(Math.Abs(other.Angle % 360) < EPSILON2);
}
else if (other.IsZero())
{
return(Math.Abs(this.Angle % 360) < EPSILON2);
}
//Vector v1 = new Vector(this.X, this.Y, this.Z),
//v2 = new Vector(axisAngle.X, axisAngle.Y, axisAngle.Z);
//int directions = Vector.CompareDirections(v1, v2);
int directions = Vector.CompareDirections(this, other);
// If axes are not parallel, they are not equivalent
if (directions == 0 || directions == 2)
{
return(false);
}
// Bring all angles to [0, 360]
double a1 = this.Angle;
while (a1 < 0)
{
a1 += 360;
}
a1 %= 360;
if (Math.Abs(a1 - 360) < EPSILON2)
{
a1 = 0;
}
double a2 = other.Angle;
while (a2 < 0)
{
a2 += 360;
}
a2 %= 360;
if (Math.Abs(a2 - 360) < EPSILON2)
{
a2 = 0;
}
// If the vectors have the same direction, angles should be module of each other.
if (directions == 1)
{
return(Math.Abs(a1 - a2) < EPSILON2);
}
// If opposite directions, they should add up to 360 degs.
if (directions == 3)
{
return(Math.Abs(a1 + a2 - 360) < EPSILON2);
}
return(false); // if here, something went wrong
}
/// <summary>
/// Creates an AxisAngle as a shallow copy of another one.
/// Internal constructor to bypass normalization.
/// </summary>
/// <param name="aa"></param>
/// <param name="normalize"></param>
internal AxisAngle(AxisAngle aa, bool normalize) : this(aa.X, aa.Y, aa.Z, aa.Angle, normalize)
{
}
/// <summary>
/// Creates an AxisAngle as a shallow copy of another one.
/// The axis vector will be automatically normalized.
/// </summary>
/// <param name="axisAngle"></param>
public AxisAngle(AxisAngle axisAngle) : this(axisAngle.X, axisAngle.Y, axisAngle.Z, axisAngle.Angle, true)
{
}
internal void UpdateAxisAngle()
{
this.AA = this.Q.ToAxisAngle();
}
/// <summary>
/// Main internal constructor.
/// </summary>
/// <param name="axisX"></param>
/// <param name="axisY"></param>
/// <param name="axisZ"></param>
/// <param name="angleDegrees"></param>
/// <param name="normalize"></param>
internal Rotation(double axisX, double axisY, double axisZ, double angleDegrees, bool normalize)
{
this.AA = new AxisAngle(axisX, axisY, axisZ, angleDegrees, normalize);
this.UpdateQuaternion();
}
public bool Rotate(AxisAngle aa)
{
return(this.Rotate(aa.ToQuaternion()));
}
