LED Crossfade function for Processing and Arduino

LEDcrossFade_Function

/*////////////////////////////////////////////////////////////////
                LED CROSSFADE FUNCTION
                
Requirements: 
  • RGB LED Arduino circuit
  • Written for Processing's Arduino/Firmata library  
    • Can be reconfigured for Arduino (without Firmata)
      by removing "arduino." before the "analogWrite" functions

Syntax: 
  LEDcrossFade(RedPin, GreenPin, BluePin,
                StartingR, StartingG, StartingB,
                DestinationR, DestinationG, DestinationB,
                Steps, Duration)
                
Parameters:
  • Red/Green/BluePin - The pin numbers/variables associated with 
                        the RGB LED
  • StartingR/G/B     - The RGB value you want to fade FROM
  • DestinationR/G/b  - The RGB value you want to fade TO
  • Steps             - Number of steps transition is broken into 
                        (higher the value, the smoother the fade)
  • Duration          - Total duration of fade (in milliseconds)

Example:
  "LEDcrossFade(9,10,11, 0,0,0, 255,255,255, 20,2000);"
  
  This will fade an RGB LED that's connected to pins 9, 10, and 11
  from off (0,0,0) to white (255,255,255) in 20 steps over 2 seconds

/////////////////////////////////////////////////////////////////*/



void LEDcrossFade(int RedPin, int GreenPin, int BluePin,
              int StartingR, int StartingG, int StartingB,
              int DestinationR, int DestinationG, int DestinationB, 
              int Steps, int Duration) {  
  
  // break fade into Steps to determine smoothness of the transition
  // and find the amount of change for each color, each step
  // in order to reach the destination in the given amount of steps 
  float RchangePerStep = (DestinationR - StartingR)/Steps;
  float GchangePerStep = (DestinationG - StartingG)/Steps;
  float BchangePerStep = (DestinationB - StartingB)/Steps;
  
  // loop through each step, displaying each color, then
  // increment each color by the given amount of change per step
  // to prepare for the next step
  for (int i = 0; i < Steps; i++){
    arduino.analogWrite(RedPin, StartingR);
    arduino.analogWrite(GreenPin, StartingG);
    arduino.analogWrite(BluePin, StartingB);
  
    StartingR += RchangePerStep;
    StartingG += GchangePerStep;
    StartingB += BchangePerStep; 
    
    // ensures that the last step brings the LED exactly to the 
    // destination color, compensating for any messy fractions.
    if(i == Steps-1){
      arduino.analogWrite(RedPin, DestinationR);
      arduino.analogWrite(GreenPin, DestinationG);
      arduino.analogWrite(BluePin, DestinationB);
    }
    
    // delay each step long enough to reach the last step
    // by the desired duration
    delay(Duration/Steps);
  }
}