Pitch detection algorithm

[Kurotenshi_pt]

Hi everyone,

I am starting out using sonic birth and my idea is to make a plugin that manages to do what I am currently doing with multiple ones.
I have some knowledge of signal processing but some more complex algorithms I'm not familiar with. Point in question, pitch detection.

Now, the first part of my project involves taking a Bass guitar signal, detecting the pitch of the note and then using that pitch to play a square wave.
I've read on the internet that zero-crossing, however resource consuming, is the fastest way to make this pitch detection but I got completely stonewalled there and could not find any algorithms. Also I'm still not to literate in the SonicBirth UI so that is why I am requesting your help.

Thank you

P.S. I've looked at the pitch shifter patches that are on the forum but I was overwhelmed and could not understand the workings