// https://www.reddit.com/r/FastLED/comments/pn9zi9/fadetoblackby_question/

#include <FastLED.h>

#define NUM_LEDS_PER_STRIP 256

CRGB leds_1[NUM_LEDS_PER_STRIP];
CRGB leds_2[NUM_LEDS_PER_STRIP];


void setup() {
  Serial.begin(115200);
  FastLED.addLeds<NEOPIXEL, 5>(leds_1, NUM_LEDS_PER_STRIP);
  FastLED.addLeds<NEOPIXEL, 6>(leds_2, NUM_LEDS_PER_STRIP);
}

void loop() {
  CRGB colOrig = CRGB(255, 128, 64);
  CRGB colFade  = colOrig;
  for (int fade = 0; fade <= 255; fade++) {
    // fade the original colour by an increasing amount
    leds_1[fade] = colOrig;
    leds_1[fade].fadeToBlackBy(fade);

    // fade a colour iteratively
    leds_2[fade] = colFade;
    colFade.fadeToBlackBy(1);

    // show the RGB values for each style
    Serial.print(leds_1[fade].r); Serial.print(", ");
    Serial.print(leds_1[fade].g); Serial.print(", ");
    Serial.print(leds_1[fade].b);
    Serial.print("  \t");
    Serial.print(leds_2[fade].r); Serial.print(", ");
    Serial.print(leds_2[fade].g); Serial.print(", ");
    Serial.println(leds_2[fade].b);
  }
  FastLED.show();
  while (1) {}
}