drawTwinkles()

void drawTwinkles

(

CRGBSet &

L

)

Examples

TwinkleFox.ino.

Definition at line 147 of file TwinkleFox.ino.

{
  // "PRNG16" is the pseudorandom number generator
  // It MUST be reset to the same starting value each time
  // this function is called, so that the sequence of 'random'
  // numbers that it generates is (paradoxically) stable.
  uint16_t PRNG16 = 11337;
  
  uint32_t clock32 = millis();
 
  // Set up the background color, "bg".
  // if AUTO_SELECT_BACKGROUND_COLOR == 1, and the first two colors of
  // the current palette are identical, then a deeply faded version of
  // that color is used for the background color
  CRGB bg;
  if( (AUTO_SELECT_BACKGROUND_COLOR == 1) &&
      (gCurrentPalette[0] == gCurrentPalette[1] )) {
    bg = gCurrentPalette[0];
    uint8_t bglight = bg.getAverageLight();
    if( bglight > 64) {
      bg.nscale8_video( 16); // very bright, so scale to 1/16th
    } else if( bglight > 16) {
      bg.nscale8_video( 64); // not that bright, so scale to 1/4th
    } else {
      bg.nscale8_video( 86); // dim, scale to 1/3rd.
    }
  } else {
    bg = gBackgroundColor; // just use the explicitly defined background color
  }
 
  uint8_t backgroundBrightness = bg.getAverageLight();
  
  for( CRGB& pixel: L) {
    PRNG16 = (uint16_t)(PRNG16 * 2053) + 1384; // next 'random' number
    uint16_t myclockoffset16= PRNG16; // use that number as clock offset
    PRNG16 = (uint16_t)(PRNG16 * 2053) + 1384; // next 'random' number
    // use that number as clock speed adjustment factor (in 8ths, from 8/8ths to 23/8ths)
    uint8_t myspeedmultiplierQ5_3 =  ((((PRNG16 & 0xFF)>>4) + (PRNG16 & 0x0F)) & 0x0F) + 0x08;
    uint32_t myclock30 = (uint32_t)((clock32 * myspeedmultiplierQ5_3) >> 3) + myclockoffset16;
    uint8_t  myunique8 = PRNG16 >> 8; // get 'salt' value for this pixel
 
    // We now have the adjusted 'clock' for this pixel, now we call
    // the function that computes what color the pixel should be based
    // on the "brightness = f( time )" idea.
    CRGB c = computeOneTwinkle( myclock30, myunique8);
 
    uint8_t cbright = c.getAverageLight();
    int16_t deltabright = cbright - backgroundBrightness;
    if( deltabright >= 32 || (!bg)) {
      // If the new pixel is significantly brighter than the background color, 
      // use the new color.
      pixel = c;
    } else if( deltabright > 0 ) {
      // If the new pixel is just slightly brighter than the background color,
      // mix a blend of the new color and the background color
      pixel = blend( bg, c, deltabright * 8);
    } else { 
      // if the new pixel is not at all brighter than the background color,
      // just use the background color.
      pixel = bg;
    }
  }
}

References AUTO_SELECT_BACKGROUND_COLOR, blend(), computeOneTwinkle(), gBackgroundColor, gCurrentPalette, CRGB::getAverageLight(), and CRGB::nscale8_video().

Referenced by loop().

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