interpolation with blend

interpolation_test_blend.ino

/*
Interpolation with blend and three buffers.
*/

#include "FastLED.h"

#define NUM_LEDS 60 

#define UPDATES_PER_SECOND 100

CRGB leds[NUM_LEDS];
CRGB lastFrame[NUM_LEDS]; // interpolation buffer
CRGB newFrame[NUM_LEDS];  // interpolation buffer

unsigned long t1; // for measuring purposes
unsigned long t2; // for measuring purposes
unsigned long t3 = 0; // for measuring purposes

uint8_t interpolationFraction = 0;
const uint8_t interpolationStepsize = 1; //2,4,8,16,32 for faster steps


uint8_t hue;

void setup() {

  FastLED.addLeds<WS2812B, 2, GRB>(leds, NUM_LEDS);
  
  FastLED.setBrightness(128);
  //FastLED.setDither(0);
  
  // Teensy pins because this is also connected in FadeCandy
  //pinMode(15, INPUT);
  //pinMode(16, INPUT);
  
  Serial.begin(57600);
  
  memset(leds, 0,  NUM_LEDS * sizeof(struct CRGB)); 
  memset(newFrame, 0,  NUM_LEDS * sizeof(struct CRGB)); 
  memset(lastFrame, 0,  NUM_LEDS * sizeof(struct CRGB)); 
  
  // populate with whiter pixels, just to see the effect
  for(int i = 0; i < NUM_LEDS; i++) {
       newFrame[i] = CHSV(0,64,255); 
  }
}

void loop()
{ setTime();
  
  if(interpolationFraction == 0)
  { 
    //hue++;
    //if(hue==255) hue = 0;
    hue = random8();
   
    // make the newFrame the lastFrame
    // memcpy is a bit faster then updating the values in the for-loop below
    memcpy8(lastFrame, newFrame, NUM_LEDS * sizeof(struct CRGB));
    
    for(int i = 0; i < NUM_LEDS; i++) {
       
       //lastFrame[i] = newFrame[i];
       newFrame[i] = CHSV(hue,255,255); 
       //leds[i] = lastFrame[i];
    }
    
    memcpy8(leds, lastFrame, NUM_LEDS * sizeof(struct CRGB));
    
  }
  else
  {  
     for(int i = 0; i < NUM_LEDS; i++) {
       leds[i] = blend(lastFrame[i], newFrame[i], interpolationFraction); 
     }
 
  } 
  
  printTime();
  
  interpolationFraction =interpolationFraction + interpolationStepsize;
  
  // we don't use 255 since that displays the new frame
  // we display the completed newframe as lastframe when fraction = 0;
  if(interpolationFraction>254) interpolationFraction = 0;
  
  //FastLED.delay(1000 / UPDATES_PER_SECOND);
  
  FastLED.show();
}

void setTime()
{   t1 = micros();
}

void printTime()
{
   t2 = micros()-t1;
   if(t2>t3) t3 = t2;
   
   Serial.print(F("update time: "));
   Serial.print(t3);
   Serial.print(" ");
   Serial.println(t2); 
  
}