pPlane</code> is
    called, the coefficients given by <em class="parameter"><code>equation</code></em> are
    transformed by the inverse of the modelview matrix and stored in the
    resulting eye coordinates. The resulting plane equation is undefined, if
    the model-view matrix <span class="emphasis"><em>M</em></span> is singular and it may be
    inaccurate, if <span class="emphasis"><em>M</em></span> is poorly conditioned. Subsequent
    changes to the modelview matrix have no effect on the stored
  