I recently took the Basic Audio Programming course offered by PointBlank, and https://www.theaudioprogrammer.com/ and this was my version of the Super Saw Synth. It was created using Klang Studio, using seven detuned SAW waves. The course is only about 4 hours long but it serves as a great intro into DSP principles. I can only recommend.
I'm also currently going through the Audio Programmer / Matthijs Hollemans books: Creating Synthesizer Plug-Ins with C++ and JUCE, and The Complete Beginner’s Guide to Audio Plug-in Development. I'm only half way through the plugin book, but it's been really great so far, a lot less academic (aka 'hard') and much more hands on learning than the Will Pirkle books (Designing Audio Effect Plugins & Designing Software Synthesizer Plugins).
