/***************************************************************
 * OLED Sine & Cosine Wave Simulator
 * Raspberry Pi Pico + SSD1306
 ***************************************************************/

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <math.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

float phase = 0;   // Phase shift for animation

void setup() {
  Wire.setSDA(4);
  Wire.setSCL(5);
  Wire.begin();

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
}

void loop() {

  display.clearDisplay();

  // Title
  display.setCursor(0, 0);
  display.println("Sine & Cosine");

  // Draw axis (middle line)
  display.drawLine(0, 32, 127, 32, WHITE);

  // Plot waves
  for (int x = 0; x < 128; x++) {

    float angle = (x * 0.1) + phase;

    int y_sin = 32 + 15 * sin(angle);
    int y_cos = 32 + 15 * cos(angle);

    // Draw pixels
    display.drawPixel(x, y_sin, WHITE);   // Sine
    display.drawPixel(x, y_cos, WHITE);   // Cosine
  }

  display.display();

  // Animate
  phase += 0.2;

  delay(30);
}