What it is
Processing made creative coding a field. A simplified Java (with the p5.js sibling for the browser), a setup() and a draw() loop, and twenty years of books, courses, and community sketches behind every question you will ever ask. Audio-reactive work uses its sound libraries for FFT and amplitude analysis, and the generative-art tradition it started feeds every tool on this map.
The visuals ceiling is set by your code and your GPU knowledge. Plain sketches look like plain sketches; shader-literate Processing work hangs in galleries.
What it costs
Free and open source on every desktop OS.
Best for
Learning to think generatively, prototyping visual ideas, album art and print work, and artists who prefer writing systems to patching them.
Skip it if
You want performance infrastructure or real-time polish without engineering. A Processing live rig is a program you wrote, with everything that implies about debugging at soundcheck.