color palette understanding

color palette understanding

#include "FastLED.h"
#define NumPixels 51       // number of LEDs in strip - count starts at 0, not 1
#define DataRate_Mhz 4     // how fast data refreshes at - [----CHECK THIS----] - slower rates are more successful when timing is not essential!!!!!
#define DataPin 11         // data pin
#define ClockPin 13        // clock Pin

CRGB leds[NumPixels];
CRGBPalette16 currentPalette;
TBlendType    currentBlending;
  
extern CRGBPalette16 myRedWhiteBluePalette;                     // don't know what this does
extern const TProgmemPalette16 myRedWhiteBluePalette_p PROGMEM; // don't know what this does

void setup()
{
  delay(1000);                                      // saftey first  
  FastLED.addLeds<APA102,DataPin,ClockPin,BGR,DATA_RATE_MHZ(DataRate_Mhz)>(leds,NumPixels);
  fill_solid(leds, NumPixels, CRGB(0,0,0));         // fill all black
  FastLED.show();                                   // show 
  Serial.begin(115200);                             // monitor speed
  pinMode(7, OUTPUT);                               // if using the prop shield this is required
  digitalWrite(7, HIGH);                            // if using the prop shield this is required
  
  currentPalette = CloudColors_p;                   // this is a pre made color palette
  currentBlending = LINEARBLEND;                    // options are LINEARBLEND or NOBLEND - linera is 'cleaner'
}

void loop() 
{
    static uint8_t startIndex = 0;
    startIndex = startIndex + 1; /* motion speed */ //seems to get it 'moving'
    
    FillLEDsFromPaletteColors( startIndex);
    
    FastLED.show();
    FastLED.delay(25);
}

void FillLEDsFromPaletteColors( uint8_t colorIndex)
{
    uint8_t brightness = 10;
    
    for( int i = 0; i < NumPixels; i++) 
    {
        leds[i] = ColorFromPalette( currentPalette, colorIndex, brightness, currentBlending);
        colorIndex += 3;
    }
}