Rainbow Palette

#include <FastLED.h>

#define LED_PIN 42
#define BRIGHTNESS  255
#define LED_TYPE    WS2811
#define COLOR_ORDER RGB

const uint8_t kMatrixWidth  = 50;
const uint8_t kMatrixHeight = 4;
const bool    kMatrixSerpentineLayout = true;


#define NUM_LEDS (kMatrixWidth * kMatrixHeight)
#define MAX_DIMENSION ((kMatrixWidth>kMatrixHeight) ? kMatrixWidth : kMatrixHeight)

// The leds
CRGB leds[kMatrixWidth * kMatrixHeight];

// The 16 bit version of our coordinates
static uint16_t x;
static uint16_t y;
static uint16_t z;

// We're using the x/y dimensions to map to the x/y pixels on the matrix.  We'll
// use the z-axis for "time".  speed determines how fast time moves forward.  Try
// 1 for a very slow moving effect, or 60 for something that ends up looking like
// water.
uint16_t speed = 1; // speed is set dynamically once we've started up

// Scale determines how far apart the pixels in our noise matrix are.  Try
// changing these values around to see how it affects the motion of the display.  The
// higher the value of scale, the more "zoomed out" the noise iwll be.  A value
// of 1 will be so zoomed in, you'll mostly see solid colors.
uint16_t scale = 30; // scale is set dynamically once we've started up

// This is the array that we keep our computed noise values in
uint8_t noise[MAX_DIMENSION][MAX_DIMENSION];

CRGBPalette16 currentPalette( PartyColors_p );
uint8_t       colorLoop = 1;

void setup() {
  delay(3000);
  LEDS.addLeds<LED_TYPE,LED_PIN,COLOR_ORDER>(leds,NUM_LEDS);
  LEDS.setBrightness(BRIGHTNESS);

  // Initialize our coordinates to some random values
  x = random16();
  y = random16();
  z = random16();
}



// Fill the x/y array of 8-bit noise values using the inoise8 function.
void fillnoise8() {
  // If we're runing at a low "speed", some 8-bit artifacts become visible
  // from frame-to-frame.  In order to reduce this, we can do some fast data-smoothing.
  // The amount of data smoothing we're doing depends on "speed".
  uint8_t dataSmoothing = 0;
  if( speed < 50) {
    dataSmoothing = 200 - (speed * 4);
  }

  for(int i = 0; i < MAX_DIMENSION; i++) {
    int ioffset = scale * i;
    for(int j = 0; j < MAX_DIMENSION; j++) {
      int joffset = scale * j;

      uint8_t data = inoise8(x + ioffset,y + joffset,z);

      // The range of the inoise8 function is roughly 16-238.
      // These two operations expand those values out to roughly 0..255
      // You can comment them out if you want the raw noise data.
      data = qsub8(data,16);
      data = qadd8(data,scale8(data,39));

      if( dataSmoothing ) {
        uint8_t olddata = noise[i][j];
        uint8_t newdata = scale8( olddata, dataSmoothing) + scale8( data, 256 - dataSmoothing);
        data = newdata;
      }

      noise[i][j] = data;
    }
  }

  z += speed;

  // apply slow drift to X and Y, just for visual variation.
  x += speed / 8;
  y -= speed / 16;
}

void mapNoiseToLEDsUsingPalette()
{
  static uint8_t ihue=0;

  for(int i = 0; i < kMatrixWidth; i++) {
    for(int j = 0; j < kMatrixHeight; j++) {
      // We use the value at the (i,j) coordinate in the noise
      // array for our brightness, and the flipped value from (j,i)
      // for our pixel's index into the color palette.

      uint8_t index = noise[j][i];
      uint8_t bri =   noise[i][j];

      // if this palette is a 'loop', add a slowly-changing base value
      if( colorLoop) {
        index += ihue;
      }

      // brighten up, as the color palette itself often contains the
      // light/dark dynamic range desired
      if( bri > 127 ) {
        bri = 255;
      } else {
        bri = dim8_raw( bri * 2);
      }

      CRGB color = ColorFromPalette( currentPalette, index, bri);
      leds[XY(i,j)] = color;
    }
  }

  ihue+=1;
}

void loop() {
  // Periodically choose a new palette, speed, and scale
  ChangePaletteAndSettingsPeriodically();

  // generate noise data
  fillnoise8();

  // convert the noise data to colors in the LED array
  // using the current palette
  mapNoiseToLEDsUsingPalette();

  LEDS.show();
  // delay(10);
}


// 1 = 5 sec per palette
// 2 = 10 sec per palette
// etc
#define HOLD_PALETTES_X_TIMES_AS_LONG 3

void ChangePaletteAndSettingsPeriodically()
{
  uint8_t secondHand = ((millis() / 1000) / HOLD_PALETTES_X_TIMES_AS_LONG) % 60;
  static uint8_t lastSecond = 99;

  if( lastSecond != secondHand) {
    lastSecond = secondHand;
    if( secondHand ==  0)  { currentPalette = CRGBPalette16(
    CHSV( 0, 255, 255),  CHSV( 16, 255, 255),  CHSV( 32, 255, 255),  CHSV( 48, 255, 255),
    CHSV( 64, 255, 255),  CHSV( 80, 255, 255),  CHSV( 96, 255, 255),  CHSV( 116, 255, 255),
    CHSV( 128, 255, 255),  CHSV( 144, 255, 255),  CHSV( 152, 255, 255),  CHSV( 160, 255, 255),
    CHSV( 180, 255, 255),  CHSV( 192, 255, 255),  CHSV( 208, 255, 255),  CHSV( 224, 255, 255) );
speed = 5; scale = 30; colorLoop = 1;}
}
}

//
// Mark's xy coordinate mapping code.  See the XYMatrix for more information on it.
//
uint16_t XY( uint8_t x, uint8_t y)
{
  uint16_t i;
  if( kMatrixSerpentineLayout == false) {
    i = (y * kMatrixWidth) + x;
  }
  if( kMatrixSerpentineLayout == true) {
    if( y & 0x01) {
      // Odd rows run backwards
      uint8_t reverseX = (kMatrixWidth - 1) - x;
      i = (y * kMatrixWidth) + reverseX;
    } else {
      // Even rows run forwards
      i = (y * kMatrixWidth) + x;
    }
  }
  return i;
}