@arturo, yes, I've read about that technique at several places. I was wondering if there was an easier way.
@hahakid, I've come across Phillip's page a couple of times, and went through it. Thanks for it 
Regarding blur addons, I want to build a simple blur oF app myself, without using any addons (to learn how it's done)
@kashim, great example. I need to learn a bit more about the GLSL language before I understand those shaders.