pd

here's a programming environment that i've used before. it's by miller puckett, the same guy who mad Max/MSP/Jitter. puredata is the freeware/opensource/prototype version of Max. apparently it's more flexible than Max which is pretty wild because i have never found an area where Max is limited. granted i've only used max for 30 days.
i feel like pd uses a lot less RAM/CPU resources because it's not half as colorful and there's not really any rounded edges or anything like that. from what i've heard if you can use pd you can use max but if you use max you can't necessarily use pd. since pd is opensource it's a lot easier to create specific function blocks using direct code.
above is a simple patch i made a long time ago to approximate a sawtooth wave by inputting a sine wave. the box that says "pd fund" is an encapsulated object that has inputs for the fundamental frequency and amplitude of the wave. coming off of those inputs are boxes that say "s amp" and "s freq". these things send the data of the frequency and the amplitude of the fundamental wave. the "r amp" and "r freq" are the receiving ends of the sent data.
Sawtooth waves have every single integer overtone. the amplitude for each overtone is the the fundamental's amplitude divided by the integer.
"dac~" sends the data to pd's digital audio converter.
wagwan.