For a while before Syd 'left' he had absolutely no control. His music was being played and he was of course the attraction of Pink Floyd, but he was utterly out of it for a long time before the band finally decided to leave him behind. David Gilmour was playing all his guitar licks, and most of the time Syd was left do what he wanted on stage, which was often standing there staring into space.

Read about it here: http://observer.guardian.co.uk/magaz...804928,00.html