/** Prepare the picking graphics context for picking */
public void render() {
// set up for rendering the pick buffer
renderer.pushDelegate(picking_context);
renderer.beginDraw();
renderer.clear();
renderer.ortho();
// render the pick buffer
SMT.getRootZone().invokePickDraw();
renderer.endDraw();
renderer.flush();
// If fast picking disabled, use loadPixels() which is really slow (max 70 fps on a high end
// card vs 200+ fps with readPixels) as a backup.
PGL pgl = renderer.beginPGL();
if (!SMT.fastPickingEnabled() || pgl == null) renderer.loadPixels();
renderer.endPGL();
renderer.popDelegate();
}