[Fluxus] slightly cleaner kludge

[gabor papp]

hi Rob,

thank you for narrowing this down. i think the blur happens in the 
prerendering stage and it is likely that the blend mode, which is set by 
the scratchpad, is not overwritten by the blend mode of the fluxus root 
state at this point. so i think the buggy behaviour is what you expect 
to be the normal one :). i'm not sure how to fix this. blurring the 
scratchpad causes this kind of behaviour. the correct way would be to 
render everything in a framebuffer and display the scratchpad on top. 
unfortunately that would mean that fluxus would not run on older 
computers without fbo support. and you would get the overexposing 
effect, but without the scratchpad text processed by the effect.

best,
gabor