Reorganization of library structure to better match Arduino spec (#20)

Note, this will also require to you "uninstall and reinstall" the Arduino library due to the library file location changes.

Reviewed-on: https://git.pinkduck.xyz/awonak/libGravity/pulls/20

src/libGravity.cpp

@@ -0,0 +1,87 @@
+/**
+ * @file libGravity.cpp
+ * @author Adam Wonak (https://github.com/awonak)
+ * @brief Library for building custom scripts for the Sitka Instruments Gravity module.
+ * @version 0.1
+ * @date 2025-04-19
+ * 
+ * @copyright MIT - (c) 2025 - Adam Wonak - adam.wonak@gmail.com
+ *
+ */
+
+#include "libGravity.h"
+
+// Initialize the static pointer for the EncoderDir class to null. We want to
+// have a static pointer to decouple the ISR from the global gravity object.
+Encoder* Encoder::_instance = nullptr;
+
+void Gravity::Init() {
+    initClock();
+    initInputs();
+    initOutputs();
+    initDisplay();
+}
+
+void Gravity::initClock() {
+    clock.Init();
+}
+
+void Gravity::initInputs() {
+    shift_button.Init(SHIFT_BTN_PIN);
+    play_button.Init(PLAY_BTN_PIN);
+
+    cv1.Init(CV1_PIN);
+    cv2.Init(CV2_PIN);
+
+    // Pin Change Interrupts for Encoder.
+    // Thanks to https://dronebotworkshop.com/interrupts/
+
+    // Enable both PCIE2 Bit3 (Port D), and PCIE1 Bit2 (Port C).
+    PCICR |= B00000110;
+    // Select PCINT23 Bit4 = 1 (Pin D4)
+    PCMSK2 |= B00010000;
+    // Select PCINT11 Bit3 (Pin D17/A3)
+    PCMSK1 |= B00001000;
+}
+
+void Gravity::initOutputs() {
+    // Initialize each of the outputs with it's GPIO pins and probability.
+    outputs[0].Init(OUT_CH1);
+    outputs[1].Init(OUT_CH2);
+    outputs[2].Init(OUT_CH3);
+    outputs[3].Init(OUT_CH4);
+    outputs[4].Init(OUT_CH5);
+    outputs[5].Init(OUT_CH6);
+    // Expansion Pulse Output
+    pulse.Init(PULSE_OUT_PIN);
+}
+void Gravity::initDisplay() {
+    // OLED Display configuration.
+    display.begin();
+}
+
+void Gravity::Process() {
+    // Read peripherials for changes.
+    shift_button.Process();
+    play_button.Process();
+    encoder.Process();
+    cv1.Process();
+    cv2.Process();
+
+    // Update Output states.
+    for (int i; i < OUTPUT_COUNT; i++) {
+        outputs[i].Process();
+    }
+}
+
+// Pin Change Interrupt on Port D (D4).
+ISR(PCINT2_vect) {
+    Encoder::isr();
+};
+// Pin Change Interrupt on Port C (D17/A3).
+ISR(PCINT1_vect) {
+    Encoder::isr();
+};
+
+// Global instance
+Gravity gravity;