#include "FastLED.h"
#include "SButton.h"

// Matrix size
#define HEIGHT 16
#define WIDTH 16
#define NUM_LEDS WIDTH * HEIGHT
#define MATRIX_TYPE 1
// LEDs pin
#define DATA_PIN 3
// LED brightness
#define BRIGHTNESS 255
// Define the array of leds
CRGB leds[NUM_LEDS];
uint32_t effTimer;
bool loadingFlag = true;
uint8_t speed = 128;
uint8_t eff = 0;
bool speedDirection = 0;
byte FF[WIDTH][HEIGHT];
byte SF[WIDTH][HEIGHT];
int shift;
Sbutton btn(2, 0, 0);
void effRun() {
  if (millis() - effTimer >= 0) {
    effTimer = millis();
    switch (eff) {
      case 0: sparkles(); break;
      case 1: sand(); break;
      case 2: fire(); break;
      case 3: snow(); break;
    }
    FastLED.show();
  }
}

void setup() {
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  btn.tick();
  effRun();
  if (btn.hasClicks() == 1) {
    eff++;
    loadingFlag=1;
  }
  if (btn.hasClicks() == 2) {
    eff--;
    loadingFlag=1;
  }
  if (btn.isHeld()) {
    speedDirection = !speedDirection;
  }
  if (btn.isHold()) {
    speed = constrain(speed + (speed / 25 + 1) * (speedDirection * 2 - 1), 1, 255);
  }
} //loop


uint16_t XY (uint8_t x, uint8_t y) {
  return ((HEIGHT - 1 - y) * WIDTH + x);
}

SimpleEffectsDemoreel.ino

diagram.json

void changeFrame() {
  memcpy(FF, SF, WIDTH * HEIGHT);
  bool checked = 0;
  for (byte x = 0; x < WIDTH; x++) {
    checked = 1; if (!SF[x][HEIGHT / 2 - HEIGHT / 8]) {
      checked = 0;
      break;
    }
  }
  if (checked) {
    for (byte y = 0; y < HEIGHT; y++) {
      for (byte x = 0; x < WIDTH; x++) {
        if (random() % 3) SF[x][y] = 0;
      }
    }
  }
  for (byte y = 0; y < HEIGHT; y++) {
    for (byte x = 0; x < WIDTH; x++) {
      if (!SF[x][y]) continue;
      if (SF[x][y] && !SF[x][y - 1] && y) {
        SF[x][y - 1] = SF[x][y];
        SF[x][y] = 0;
      }
      else if (SF[x][y] && SF[x][y - 1] && !SF[x + 1][y - 1]  && !(x == WIDTH - 1) && y) {
        SF[x + 1][y - 1] = SF[x][y];
        SF[x][y] = 0;
      }
      else if (SF[x][y] && SF[x][y - 1] && !SF[x - 1][y - 1] && x && y) {
        SF[x - 1][y - 1] = SF[x][y];
        SF[x][y] = 0;
      }
    }
  }
  if (!(random() % 4)) SF[WIDTH / 2][HEIGHT - 1] = random(10, 255);
}
void sand() {
  if(loadingFlag){
    memset8(SF, 0,NUM_LEDS);
    memset8(FF, 0,NUM_LEDS);
    shift = 0;
    loadingFlag = 0;
  }
  shift += speed;
  if (shift >= 255) {
    changeFrame();
    shift = 0;
  }
  for (byte y = 0; y < HEIGHT; y++) {
    for (byte x = 0; x < WIDTH; x++) {
      CRGB col1 = CHSV(FF[x][y], 255, (FF[x][y]) ? 255 : 0);
      leds[XY(x, y)] = nblend(col1, CHSV(SF[x][y], 255, (SF[x][y]) ? 255 : 0), shift);
    }
  }
}

Sand.ino

void fire() {
  if(loadingFlag){
    loadingFlag = 0;
  }
  static uint32_t t;
  t += speed;
  for (byte x = 0; x < WIDTH; x++) {
    for (byte y = 0; y < HEIGHT; y++) {

      int16_t Bri = inoise8(x * 90, (y * 90) - t) - (y * (255 / HEIGHT));
      byte Col = Bri;// inoise8(x * scale, (y * scale) - t) - (y * (255 / HEIGHT));
      if (Bri < 0) Bri = 0; if (Bri != 0) Bri = 256 - (Bri * 0.2);
      nblend(leds[XY(x, y)], ColorFromPalette(HeatColors_p, Col, Bri), speed);
    }
  }
}

Fire.ino

void snow() {
  if(loadingFlag){
    memset8(SF, 0,NUM_LEDS);
    memset8(FF, 0,NUM_LEDS);
    shift = 0;
    loadingFlag = 0;
  }
  for (byte x = 0; x < WIDTH; x++) {
    for (byte y = 0; y < HEIGHT; y++) {
      CRGB col = CHSV(0, 0, (FF[x][y]) ? 255 : 0);
      leds[XY(x, y)] = nblend(col, CHSV(0, 0, (SF[x][y]) ? 255 : 0), shift);
    }
  }
  shift += speed;
  if (shift >= 255) {
    memcpy(FF, SF, WIDTH * HEIGHT);
    for (byte x = 0; x < WIDTH; x++) {
      for (byte y = 0; y < HEIGHT; y++) {
        if (SF[x][y] && y)
        {
          SF[x][y - 1] = 255;
          SF[x][y] = 0;
        }
        else if (SF[x][y] && !y) {
          SF[x][y] = 0;
        }
      }
    } if (random() % 2)SF[random(0, WIDTH)][HEIGHT - 1] = 255;
    shift %= 255;
  }
}

Snow.ino

# Wokwi Library List
# See https://docs.wokwi.com/guides/libraries

# Automatically added based on includes:
FastLED

Sbutton

libraries.txt

void sparkles(){
  if(loadingFlag){
    memset8(SF, 0,NUM_LEDS);
    memset8(FF, 0,NUM_LEDS);
    shift = 0;
    loadingFlag = 0;
  }
  for(byte i = 0; i < map(speed,1,255,2,16); i++){
    uint8_t x = random(0,WIDTH);
    uint8_t y = random(0,HEIGHT);
    if(!SF[x][y]){
    SF[x][y]=255;
    FF[x][y]=random(0,255);
  }}
  for(byte x = 0; x < WIDTH; x++){
    for(byte y = 0; y < HEIGHT; y++){
      if(SF[x][y]<=30) SF[x][y]=0;
      else SF[x][y]=((SF[x][y]-map(speed,1,255,1,16))<=0)?0:(SF[x][y]-map(speed,1,255,1,16));
      leds[XY(x,y)]=CHSV(FF[x][y],255,SF[x][y]);
    }}
}