c++arrayssparkcorefastled

C++ Array Values Not Changing


I am working with FastLED on a Particle Photon in C++ and am trying to assign a new value to one of the elements of the pixel array.

Essentially, I have a array declared as such:

NSFastLED::CRGB leds[1];

I pass this into an "animation" class I've written in order to change the LED values:

void SomeClass::loop()
{
  // Get the pointer to the current animation from a vector
  Animation *currentAnim = animations.at(currentAnimation);
  currentAnim->animate(leds);

  ...
}

In the animation, I am trying to do something really simple-- set an element of that LED array to some value. For testing, even setting it to a static integer "0" would be fine.

void MyAnimation::animate(NSFastLED::CRGB *leds)
{
  for(int i = 0; i < numLeds; i++)
  {
    Serial.print(leds[i]); // "1"

    leds[i] = 0;

    Serial.print(leds[i]); // "1"
  }
}

The issue is, the array element is not being set at all. As you can see, this is even inside of the animation class that I am having the issue. I've also tried using (leds*)[i] = 0, but that doesn't have any effect either.

Why is it that the value is not being set in the array?


Solution

  • Your array data type is NSFastLED::CRGB, this holds RGB values, and can be assigned like below (from https://github.com/FastLED/FastLED/wiki/Pixel-reference )

    If you just want to store a number you could use int instead of NSFastLED::CRGB.

    // The three color channel values can be referred to as "red", "green", and "blue"...
      leds[i].red   = 50;
      leds[i].green = 100;
      leds[i].blue  = 150;
    
      // ...or, using the shorter synonyms "r", "g", and "b"...
      leds[i].r = 50;
      leds[i].g = 100;
      leds[i].b = 150;
    
    
          // ...or as members of a three-element array:
          leds[i][0] = 50;  // red
          leds[i][1] = 100; // green
          leds[i][2] = 150; // blue