I would add to that VCV Rack [1] is another great starting point.
Very low barrier to entry, see developer manual [2], hundreds open source modules to learn from. [3]
[2] https://vcvrack.com/manual/PluginDevelopmentTutorial
[3] https://github.com/search?o=desc&q=vcv&s=&type=Repositories
I saw this the other day that lets reuse gen~ code from Max as a VCV module: https://github.com/isabelgk/gen-rack
I don't know much about audio programming, but here's a question.
When emulating sounds from physical instruments, can you get close by using only code without using audio samples? If yes, is it harder/easier?
I believe Audio Modelling are one of the leaders in this field: https://audiomodeling.com/
In terms of harder/easier... I'd guess it's a lot harder to code, but easier in terms of not having to sample thousands of different articulations for each instrument! Judging by the huge selection of sampled physical instruments and the small amount of synthesised ones, I guess overall harder. Would be interesting to hear from someone who knows more though!
I assume you've seen the Blueprint project for building React UIs on top of JUCE? Very interested to hear more details about what you've been working on whenever you have something ready to share!
My primary motivations for doing something different was that Blueprint currently doesn't work on mobile (and I'm not sure it could ship on the iOS app store currently, with it using Duktape), and I wanted to get away from writing any C++ at all for the UI – and also that I love playing with this kind of stuff, heh. The app that I work on is built using React Native and JUCE (and Unity), so it's an area I have a lot of thoughts about!
TBH the web stuff started out as an experiment, but I'm actually pretty impressed by how practical web is for building UIs – I've got some nice integration going on to make it pretty natural to write plugin UIs. I'll post it on here when it's ready, but if you have a Twitter/email/whatever you'd like to share or can contact me via mine in my profile, I'd be happy to share with you in advance – I'd love to get feedback from people interested in this area.
My understanding of Rust audio programming is that it is possible, but still fairly early days... something like JUCE provides a huge amount out of the box that you might not initially appreciate, e.g. it abstracts away the details of all the different plugin formats and all the different platform's audio APIs, and it has been around for long enough that you can be confident it does it well.
I'm really curious about Rust as it feels like a nicer language to work with than C++, but if you are serious about building professional audio software I personally don't think you can avoid C++ so you might as well embrace it.
I have a feeling that with Rust, you'd spend half your time figuring out how to do stuff that JUCE does out of the box, which is fine if you are interested in the figuring out part, but ultimately it might not help you focus on the actual audio programming.
Also there are a tonne of resources on C++ and especially JUCE out there, never underestimate the power of being able to Google for your answers!
Edit: on the C++ side, I found Bjarne Stroustrup's "C++ Programming Language" book quite a good way to understand the fundamentals. To be honest, I usually learn new languages just by doing and Googling, but with C++ it quickly became apparent after the 100th mystery crash that I'd actually have to understand what was going on under the hood with memory etc!
One thing to watch out for is that the language has evolved a lot recently, but a lot of code samples are still written in an old style. You want to make sure you are using “modern” C++ (e.g. post C++11) features where possible e.g. smart pointers. It can be a bit confusing as some JUCE classes have been superseded by the C++ standard library, they date back to the days before “modern C++”... but I wouldn’t stress too much, using the JUCE versions is usually equally fine.
No, you can do with C just fine.
What is your background, and which parts of audio programming would you like to focus on? e.g. are you interested in writing your own low-level DSP code, or more interested in hooking together higher-level blocks?
If you're from a web programming background, you can have a lot of fun with the WebAudio API [1]. It provides high level building blocks like oscillators, filters, effects, etc., which you can hook together. It has some rough edges but it's a great starting point.
Tone.js [2] is a great way to get started with WebAudio, it provides some useful abstractions that let you build fun things quickly, and there are some great examples of WebAudio creativity out there e.g. Blokdust [3]. If you want to go lower level, all major browsers now support the AudioWorklet API [4], which lets you write your own custom DSP algorithms and have them run efficiently within WebAudio.
However, WebAudio has limitations in terms of performance, and you can't use a WebAudio synth as a plugin in your music production software of choice (well, you might be able to get a browser which runs as a plugin, but it's not going to be ideal!).
If you want to write professional audio code, you can't really avoid working with C++ - it's the industry standard approach. This is largely because C++ allows programmers to very carefully design the performance characteristics of their code - specifically, you can avoid doing anything which might take an unknown amount of time (e.g. allocating new memory, locking) while processing on your audio thread - audio is realtime and very low latency, so you need to be sure your code is going to run in the amount of time you think it will.
Personally, I think JUCE [5] is a great starting point. It abstracts away some of the complexities of both C++ and audio APIs, allowing you to build cross platform audio apps and plugins without having to worry about platform-specific quirks. They have a pretty good selection of tutorials too [6]. An alternative you could look into is iPlug2 [7]. There are a couple of books by Will Pirkle on the topic of programming audio effects and synths with C++ - the author uses his own framework, but the same principles apply to other frameworks. Make sure you get the new editions if you do get these.
You'll probably want to take time to learn some C++ basics first if you don't already know it, it's a hard language to master! I'm actually working on an integration right now to allow you to build web UIs for JUCE apps, which takes away the complexity of also building the UI in C++ - I'll hopefully have something to share in the next few weeks.
If you want something a bit more straightforward and you're happy just supporting MacOS and iOS, AudioKit [8] is worth a look. It's kind of in between WebAudio and JUCE in terms of complexity I'd say - you write your code in Swift and it provides a load of high level building blocks, but you can drop down to a lower level if you need to write your own stuff in C++. Also the CoreAudio/CoreMIDI APIs on Apple platforms are very powerful, though I've struggled to find great documentation.
One other option you could look at are specialist audio languages like Supercollider [9] and Faust [10], or visual programming tools like Max [11] or Pure Data [12]. I'm not very well versed in any of these, but I've heard good things about Supercollider especially.
Phew, hope that helps! As you can probably tell, I'm really interested in this stuff so please give me a shout with any questions!
Edit: one more resource I remembered, there's a Youtube channel dedicated to learning audio programming, mostly using JUCE, called The Audio Programmer [13]. I haven't actually watched much content so can't say too much about that, but I know the guy behind it and he's great, and also runs a great community for people interested in audio programming [14].
[1] https://developer.mozilla.org/en-US/docs/Web/API/Web_Audio_A...
[2] https://tonejs.github.io/
[3] https://blokdust.com/
[4] https://developer.mozilla.org/en-US/docs/Web/API/AudioWorkle...
[5] https://juce.com
[6] https://juce.com/learn/tutorials
[7] https://github.com/iPlug2/iPlug2
[8] https://audiokit.io/
[9] https://supercollider.github.io/
[10] https://faust.grame.fr/
[11] https://cycling74.com/
[12] https://puredata.info/
[13] https://www.youtube.com/channel/UCpKb02FsH4WH4X_2xhIoJ1A
[14] https://theaudioprogrammer.com/community/