#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <SPI.h>

#define TFT_CS     2
#define TFT_RST    4
#define TFT_DC     5

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

int mapValue(float value, float fromLow, float fromHigh, float toLow, float toHigh) {
  return int((value - fromLow) * (toHigh - toLow) / (fromHigh - fromLow) + toLow);
}

void drawSineWave() {
  const int LCD_WIDTH = tft.width();
  const int LCD_HEIGHT = tft.height();

  tft.fillScreen(ILI9341_BLACK);
  tft.setTextColor(ILI9341_WHITE);
  tft.setTextSize(2);

  for (int x = 0; x < LCD_WIDTH; x++) {
    float radians = (x / float(LCD_WIDTH)) * TWO_PI;
    float sineValue = sin(radians);
    
    int y = mapValue(sineValue, -1, 1, 0, LCD_HEIGHT);
    
    tft.drawPixel(x, y, ILI9341_WHITE);
  }

  tft.setCursor(0, 0);
  tft.print("Sine Wave");
}

void setup() {
  tft.begin();
  tft.setRotation(3);
  drawSineWave();
}

void loop() {
}