public RenderQueue()
{
// set the default queue group for this queue
defaultGroup = RenderQueueGroupID.Main;
// create the main queue group up front
renderGroups.Add(
RenderQueueGroupID.Main,
new RenderQueueGroup( this, splitPassesByLightingType,
splitNoShadowPasses,
shadowCastersCannotBeReceivers ) );
}