private void _translate3Dto2DPixels( Camera camera, Vector3 vertex, out int x, out int y )
{
// calculate hsc screen coordinates
Vector3 hsc = _translate3Dto2D( camera, vertex );
// convert to window position in pixels
//RenderTarget *rt = Root.Instance.RenderTarget(in.getName());
//if ( !rt )
// throw new AxiomException( string.Format( "Can't find '{0}' render target", mpWin.getName() ) );
x = (int)( ( hsc.x + 1.0f ) / 2.0f * 640.0f );
y = (int)( ( -hsc.y + 1.0f ) / 2.0f * 480.0f );
}