Set this matrix to a rotation transformation to make <code>-z</code>
point along <code>dir</code>.
<p>
This is equivalent to calling
{@link #setLookAt(ref Vector3d, Vector3d, Vector3d) setLookAt()}
with <code>eye = (0, 0, 0)</code> and <code>center = dir</code>.
<p>
In order to apply the lookalong transformation to any previous existing transformation,
use {@link #lookAlong(ref Vector3d, Vector3d)}.
Set this matrix to a rotation transformation to make <code>-z</code> point along <code>dir</code>. <p> This is equivalent to calling {@link #setLookAt(ref Vector3d, Vector3d, Vector3d) setLookAt()} with <code>eye = (0, 0, 0)</code> and <code>center = dir</code>. <p> In order to apply the lookalong transformation to any previous existing transformation, use {@link #lookAlong(ref Vector3d, Vector3d)}.
@see #setLookAlong(ref Vector3d, Vector3d) @see #lookAlong(ref Vector3d, Vector3d)
@param dir the direction in space to look along @param up the direction of 'up' @return this