WLED/usermods/user_fx/user_fx.cpp

#include "wled.h"

// for information how FX metadata strings work see https://kno.wled.ge/interfaces/json-api/#effect-metadata

// static effect, used if an effect fails to initialize
static void mode_static(void) {
  SEGMENT.fill(SEGCOLOR(0));
}

#define FX_FALLBACK_STATIC { mode_static(); return; }

// If you define configuration options in your class and need to reference them in your effect function, add them here.
// If you only need to use them in your class you can define them as class members instead.
// bool myConfigValue = false;

/////////////////////////
//  User FX functions  //
/////////////////////////

// Diffusion Fire: fire effect intended for 2D setups smaller than 16x16
static void mode_diffusionfire(void) {
  if (!strip.isMatrix || !SEGMENT.is2D())
    FX_FALLBACK_STATIC;  // not a 2D set-up

  const int cols = SEG_W;
  const int rows = SEG_H;
  const auto XY = [&](int x, int y) { return x + y * cols; };

  const uint8_t refresh_hz = map(SEGMENT.speed, 0, 255, 20, 80);
  const unsigned refresh_ms = 1000 / refresh_hz;
  const int16_t diffusion = map(SEGMENT.custom1, 0, 255, 0, 100);
  const uint8_t spark_rate = SEGMENT.intensity;
  const uint8_t turbulence = SEGMENT.custom2;

unsigned dataSize = cols * rows;  // SEGLEN (virtual length) is equivalent to vWidth()*vHeight() for 2D
  if (!SEGENV.allocateData(dataSize))
    FX_FALLBACK_STATIC;  // allocation failed

  if (SEGENV.call == 0) {
    SEGMENT.fill(BLACK);
    SEGENV.step = 0;
  }

  if ((strip.now - SEGENV.step) >= refresh_ms) {
    // Keep for ≤~1 KiB; otherwise consider heap or reuse SEGENV.data as scratch.
    uint8_t tmp_row[cols];
    SEGENV.step = strip.now;
    // scroll up
    for (unsigned y = 1; y < rows; y++)
      for (unsigned x = 0; x < cols; x++) {
        unsigned src = XY(x, y);
        unsigned dst = XY(x, y - 1);
        SEGENV.data[dst] = SEGENV.data[src];
      }

    if (hw_random8() > turbulence) {
      // create new sparks at bottom row
      for (unsigned x = 0; x < cols; x++) {
        uint8_t p = hw_random8();
        if (p < spark_rate) {
          unsigned dst = XY(x, rows - 1);
          SEGENV.data[dst] = 255;
        }
      }
    }

    // diffuse
    for (unsigned y = 0; y < rows; y++) {
      for (unsigned x = 0; x < cols; x++) {
        unsigned v = SEGENV.data[XY(x, y)];
        if (x > 0) {
          v += SEGENV.data[XY(x - 1, y)];
        }
        if (x < (cols - 1)) {
          v += SEGENV.data[XY(x + 1, y)];
        }
        tmp_row[x] = min(255, (int)(v * 100 / (300 + diffusion)));
      }

      for (unsigned x = 0; x < cols; x++) {
        SEGENV.data[XY(x, y)] = tmp_row[x];
        if (SEGMENT.check1) {
          uint32_t color = SEGMENT.color_from_palette(tmp_row[x], true, false, 0);
          SEGMENT.setPixelColorXY(x, y, color);
        } else {
          uint32_t base = SEGCOLOR(0);
          SEGMENT.setPixelColorXY(x, y, color_fade(base, tmp_row[x]));
        }
      }
    }
  }
}
static const char _data_FX_MODE_DIFFUSIONFIRE[] PROGMEM = "Diffusion Fire@!,Spark rate,Diffusion Speed,Turbulence,,Use palette;;Color;;2;pal=35";


/////////////////////
//  UserMod Class  //
/////////////////////

class UserFxUsermod : public Usermod {
 private:
 public:
  void setup() override {
    strip.addEffect(255, &mode_diffusionfire, _data_FX_MODE_DIFFUSIONFIRE);

    ////////////////////////////////////////
    //  add your effect function(s) here  //
    ////////////////////////////////////////

    // use id=255 for all custom user FX (the final id is assigned when adding the effect)

    // strip.addEffect(255, &mode_your_effect, _data_FX_MODE_YOUR_EFFECT);
    // strip.addEffect(255, &mode_your_effect2, _data_FX_MODE_YOUR_EFFECT2);
    // strip.addEffect(255, &mode_your_effect3, _data_FX_MODE_YOUR_EFFECT3);
  }

  
  ///////////////////////////////////////////////////////////////////////////////////////////////
  //  If you want configuration options in the usermod settings page, implement these methods  //
  ///////////////////////////////////////////////////////////////////////////////////////////////

  // void addToConfig(JsonObject& root) override
  // {
  //   JsonObject top = root.createNestedObject(FPSTR("User FX"));
  //   top["myConfigValue"] = myConfigValue;
  // }
  // bool readFromConfig(JsonObject& root) override
  // {
  //   JsonObject top = root[FPSTR("User FX")];
  //   bool configComplete = !top.isNull();
  //   configComplete &= getJsonValue(top["myConfigValue"], myConfigValue);
  //   return configComplete;
  // }

  void loop() override {} // nothing to do in the loop
  uint16_t getId() override { return USERMOD_ID_USER_FX; }
};

static UserFxUsermod user_fx;
REGISTER_USERMOD(user_fx);