// ================================================================================
public Matrix3D GetTextureXfrm()
{
// ensure bitmap of texture is loaded
if (this.Texture.IsBitmapLoaded == false)
{
this.Texture.LoadBitmap();
}
// generate texture transform
Matrix3D xfrm = Matrix3D.FromBasis(this.SAxis, this.TAxis, Vector3D.Cross(this.SAxis, this.TAxis));
xfrm.Scale(this.Texture.Width, this.Texture.Height, 1);
xfrm.Invert();
return(xfrm);
}