How to change between sketches?

edited December 2017 in Library Questions


I have a long VJ performance to do and each song is fairly long and I'll need to be able to change between my sketches during it, how can I smoothly transition from one sketch to another?




  • @aidinz -- if you want to do live transitions and/or live coding then you probably also want a framework that treats your Processing sketches like patches. Check out Praxis Live. From the website:

    ... imagine combining the best of Processing with the best of visual patchers like Isadora or Quartz Composer; imagine components defined like Processing sketches, so you're never constrained by what comes built-in; imagine forking components or creating new ones while your project is running ...

    Forum announcement:

    If you don't want to use a full system and just want to jury-rig a simple setup, you could:

    1. incorporate two sketches into one sketch, with each sketch drawing to a simple PGraphics buffer.
    2. Implement a cross-fade that starts the new sub-skech drawing to its PGraphics buffer, then fades between the two PGraphics and stops the old sub-sketch. Here is an example of doing this with two videos rather than two sketch functions, but it is the same process:
  • Thanks.

    I was googling around and people were not that happy with Praxis. Have you done any shows with it? Is it stable enough? Are you happy with it?

    And for the second suggestion, I think it will be expensive to draw all sketches and just display one(s) you want, if I understand you re PGraphics buffer correctly that is.

    Someone mentioned I can put sketches in different tabs and call them via a main controller sketch but I'm yet to make it work.

  • I have no live performance experience with Praxis. Often VJ/livecoding setups are so specific that the best way to know if a tool will meet your needs is to test it yourself.

    Crossfading graphics works the way it does in crossfading music. You aren't playing all of the songs all at once -- you are only playing either 1 song or, during the fade, 2 songs. Once the fade is over you stop playing song A and only play song B.

    re: "I think it will be expensive" -- running two graphics buffers can't be more expensive than running two completely separate sketches. It can only be as expensive or less so, depending on your sketch overhead and how you optimize.

  • Sorry, not on here much these days - just seen this ...

    I was googling around and people were not that happy with Praxis.

    Interesting! I'd love to read those - we're currently working on Praxis LIVE v4 so be good to address any issues.

    It's as stable as the underlying Processing framework - in fact, more so in a few respects! ;-)

    And for the second suggestion, I think it will be expensive to draw all sketches and just display one(s) you want,

    This is something Praxis LIVE has built-in support to handle - it only renders what is necessary for output to screen.

  • @neilcsmith_net I tried running praxis Live to see what it was all about but it didn't work for me. I mean, it is not clear to me what it does (Notice: I didn't try hard to be fair) I felt praxis is directed to certain public and I am not part of that public. I watch two of your videos and it was not clear what was going on. I am interested to learn more about it since I have seen people making good comments about it.


  • @kfrajer fair enough! To answer your question, it's aimed at Java / Processing coders. It's an IDE (replacement for PDE based on Apache NetBeans) and runtime. For Processing usage specifically it supports a few useful things - splitting projects up into multiple "sketches", connecting them graphically (node-based) at runtime, running multiple pipelines in one project (across computers if you want), and live / interactive coding - immediate updates on code changes without restarting.

    If you ever need help getting started with it just ask me! :-)

Sign In or Register to comment.