I have been trying to get into shaders and have managed some basics from tutorials. I haven't found any processing specific tutorials about multi-pass shaders and was wondering if anyone could give me an example of how to implement one. I have seen examples of shaders themselves but i don't know how to use them with processing.

I am hoping to eventually have a multi-pass shader for bluring points and lines relative to there depth.

Is it possible to edit and read a text document using processing.

For example have one program to act as a map editor for a game and have a second program to run the game and load the map you created.

 Any help or suggestions for alternatives would be useful.