Listed below you’ll find a Basic collection of useful Processing libraries as well as additional links and resources with a focus on sound output/realtime manipulation, video/vector/pdf export and extensions that enable communication through/between several data protocols and software interfaces like XML, MySQL, OpenSound Control (OSC) and Max/MSP.
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For further information about writing and using external libraries, visit the discourse at Processing.org.
Image source: XFUNS – Processing images by Marius Watz, 2003