encoderloop.cpp

#include <inttypes.h>
#include <Encoder.h>

const int ShiftPin = 0;   // This is the button to activate Alternate action for buttons and 8 first encoders
const int ledPin = 32;    // This LED when HIGH shows the Shift Button is pressed

struct EncoderValue {
    EncoderValue(uint8_t ccParameter) :
        value(0)
        , ccParameter(ccParameter) {
    }

    uint8_t value;
    const uint8_t ccParameter;

    void update(uint8_t value) {
        if (value != this->value) {
            usbMIDI.sendControlChange(ccParameter, value, 1);
            this->value = value;
        }
    }
};

struct MidiEncoder {
    MidiEncoder(int a, int b, uint8_t ccParameter, uint8_t shiftCCParameter) :
        encoder(a, b)
        , value(ccParameter)
        , shiftValue(shiftCCParameter) {
    }

    void update(bool isShiftHeld) {
        const int value = constrain(encoder.read(), 0, 127);
        encoder.write(value);
        if (isShiftHeld) {
            shiftvalue.update(value);
        } else {
            value.update(value);
        }
    }

    Encoder encoder;
    EncoderValue value;
    EncoderValue shiftValue;
};

MidiEncoder midiEncoders[16] = {
    Encoder(1, 2, 66, 74),
    Encoder(3, 4, 67, 75),
    Encoder(5, 6, 68, 76),
    Encoder(7, 8, 69, 77),
    Encoder(9, 10, 70, 78),
    Encoder(11, 12, 71, 79),
    Encoder(14, 15, 72, 80),
    Encoder(16, 17, 73, 81),
};

void setup() {
    pinMode(ShiftPin, INPUT_PULLUP);
    pinMode(ledPin, OUTPUT);
}

void loop() {
    const int ShiftState = digitalRead(ShiftPin);
    delay(10);
    digitalWrite(ledPin, ShiftState);

    for (int i = 0; i < 8; i++) {
        const bool isShiftHeld = ShiftState == HIGH;
        midiEncoders[i].update(isShiftHeld);
    }
}