some things off the top of my head:
See Dan Shiffman's youtube channel and Nature of Code. The latter is for Processing but I believe a lot of the youtube videos are for p5.js, which is a Processing-inspired javascript library.
If you want to do C++, I suggest looking at Cinder or openFrameworks.
For doing things with geometry, I've found Paul Bourke's site amazingly helpful (though this is a bit more math oriented and is less 'generative' and more geometry).
Anders Hoff has a good overview of some popular generative algorithms with some code on github.



Hobby ProgrammingGenerative art resources?May 24, 2016 at 10:13 PM