/// <summary>
/// Decomposes a matrix into a scale, rotation, and translation.
/// </summary>
/// <param name="scale">When the method completes, contains the scaling component of the decomposed matrix.</param>
/// <param name="rotation">When the method completes, contains the rtoation component of the decomposed matrix.</param>
/// <param name="translation">When the method completes, contains the translation component of the decomposed matrix.</param>
/// <remarks>
/// This method is designed to decompose an SRT transformation matrix only.
/// </remarks>
public bool Decompose(out XbimVector3D scale, out XbimQuaternion rotation, out XbimVector3D translation)
{
//Source: Unknown
// References: http://www.gamedev.net/community/forums/topic.asp?topic_id=441695
// via https://code.google.com/p/sharpdx/source/browse/Source/SharpDX/Matrix.cs?r=9f9e209b1be04f06f294bc6d72b06055ad6abdcc
//Get the translation.
translation = new XbimVector3D();
translation.X = this._offsetX;
translation.Y = this._offsetY;
translation.Z = this._offsetZ;
//Scaling is the length of the rows.
scale = new XbimVector3D();
scale.X = Math.Sqrt((M11 * M11) + (M12 * M12) + (M13 * M13));
scale.Y = Math.Sqrt((M21 * M21) + (M22 * M22) + (M23 * M23));
scale.Z = Math.Sqrt((M31 * M31) + (M32 * M32) + (M33 * M33));
//If any of the scaling factors are zero, than the rotation matrix can not exist.
//
double ZeroTolerance = 0.000003;
if (Math.Abs(scale.X) < ZeroTolerance ||
Math.Abs(scale.Y) < ZeroTolerance ||
Math.Abs(scale.Z) < ZeroTolerance)
{
rotation = new XbimQuaternion(); // defaults to identity
return(false);
}
//The rotation is the left over matrix after dividing out the scaling.
XbimMatrix3D rotationmatrix = new XbimMatrix3D();
rotationmatrix.M11 = M11 / scale.X;
rotationmatrix.M12 = M12 / scale.X;
rotationmatrix.M13 = M13 / scale.X;
rotationmatrix.M21 = M21 / scale.Y;
rotationmatrix.M22 = M22 / scale.Y;
rotationmatrix.M23 = M23 / scale.Y;
rotationmatrix.M31 = M31 / scale.Z;
rotationmatrix.M32 = M32 / scale.Z;
rotationmatrix.M33 = M33 / scale.Z;
rotationmatrix.M44 = 1;
XbimQuaternion.RotationMatrix(ref rotationmatrix, out rotation);
return(true);
}
