GLASS2 with M5ATOM-S3

main.cpp

#include <M5UnitGLASS2.h>
M5UnitGLASS2 display (2, 1, 400000);

constexpr size_t POINTS = 128;
int points[POINTS];

void setup() {
  display.init();
  display.startWrite();
  display.fillScreen(TFT_BLACK);

  if (display.width() < display.height()) {
    display.setRotation(display.getRotation() ^ 1);
  }
  for (auto x = 0; x < POINTS; ++x) {
    points[x] = -1;
  }
  display.display();
}

void loop() {
  static int amplitude = 0;
  static int delta = 1;
  amplitude += delta;
  if (amplitude >= 32) {
    delta = -1;
  } else if (amplitude <= 0) {
    delta = 1;
  }

  display.waitDisplay();
  for (int x = 0; x < POINTS; ++x) {
    const float freq = 5.f * sin(2 * PI * millis() / 10000.0);
    const float fy = amplitude * sin(2 * PI * freq * x / 128);
    const int y =  map(fy, -32, 32, 0, 64 - 1);
    if (points[x] == y) {
      continue;
    }
    display.drawPixel(x, points[x], BLACK);
    display.drawPixel(x, y, WHITE);
    points[x] = y;
  }
  display.display();
}