// Animates white pixels to simulate flying through a star field

#include <SPI.h>
#include <TFT_eSPI.h>

// Use hardware SPI
TFT_eSPI tft = TFT_eSPI();

// With 1024 stars the update rate is ~65 frames per second
#define NSTARS 1024
uint8_t sx[NSTARS] = {};
uint8_t sy[NSTARS] = {};
uint8_t sz[NSTARS] = {};

uint8_t za, zb, zc, zx;

// Fast 0-255 random number generator from http://eternityforest.com/Projects/rng.php:
uint8_t __attribute__((always_inline)) rng()
{
  zx++;
  za = (za^zc^zx);
  zb = (zb+za);
  zc = ((zc+(zb>>1))^za);
  return zc;
}