Controlp5 - Multiple buttons that use one function

Do you mean something like this?

import controlP5.*;

ControlP5 cp5;

void setup() {
  size(800, 400);
  cp5 = new ControlP5(this);
  cp5.addButton("A").setPosition(40, 40);
  cp5.addButton("B").setPosition(40, 60);
  cp5.addButton("C").setPosition(40, 80);
}

void draw() {
  background(0);
}

void controlEvent(CallbackEvent event) {
  if (event.getAction() == ControlP5.ACTION_CLICK) {
    switch(event.getController().getAddress()) {
    case "/A":
      println("Button A Pressed");
      break;
    case "/B":
      println("Button B Pressed");
      break;
    case "/C":
      println("Button C Pressed");
      break;
    }
  }
}

It’s based on the example called ControlP5callback.