The RGB Throbber

rgb_throb.this.is.not.c

/*
 * "Throb" effect ( Part Deux )
 *
 * Paul Tagliamonte, 2010. ( Peace, Love and C++, baby )
 *
 *  This code is released under the Bacon license.
 *  If you like this code enough, consider sending me bacon.
 *
 *  That or GPL-3+. 
 *
 */

int incomingByte = -1;

int lred   = 3;
int lgreen = 5;
int lblue  = 6;

int highMask = 3;
int lowMask  = 0;

int adder    = 1;    // how much to jump by.
// This will be inverted later.

int slope       = 4; // y = (slope) x 
int accumulator = 0;  // part of bresie's algorithm

int cycle   = 15;    // duty ( hehehehe, doodie ) cycle
int on      = 10;    // How long "on" is per cycle.
int bottom  = 0;     // What "off" is

void setup() {
  pinMode(lred,   OUTPUT);
  pinMode(lgreen, OUTPUT);
  pinMode(lblue,  OUTPUT);
}

void loop() {
  
  /*
   * Credit where credit is due:
   *  The following is an adaption of Bresenham's line algorithm.
   *  
   * To future CS students, as well as current CS students:
   *  Please pay attention in class. You never know when the most
   *  inconsequential algorithm for the most obscure and backwards
   *  example will come in handy. This algorithm was originally
   *  to draw lines.
   *
   *  Now, the reason I use this is one big reason and one big reason
   *  only: It does not use division or floating point numbers to do
   *  computation. This was by design ( since such operations would
   *  bog down a CPU by a large factor when done over 10,000,000,000
   *  times ). Since the Arduino sucks with floating point numbers,
   *  and since it's a cute ARM processor, this is a perfect fit.
   *
   * Stay in school, kids. Listen to your parents.
   *
   * Oh yes, and go to class. For the love of christ, go to class.
   *
   */

  accumulator = accumulator + 1; // on cycle length
  if ( accumulator > slope ) { // if we've gone far enough X to jump a Y
    accumulator = 0;         //  then: - reset the counter
    on = on + adder;         //        - pop the "line" up one "Y"

    if ( on >= cycle || on <= bottom ) {
      adder = -adder; // if we're at the border, invert the adder for the next go-around.
    }
  }

  
  if ( on <= bottom )
      highMask = random(1,7);

  int rgbMask = highMask;

  int rHigh = rgbMask % 2;
  rgbMask = rgbMask / 2;

  int gHigh = rgbMask % 2;
  rgbMask = rgbMask / 2;

  int bHigh = rgbMask % 2;
  rgbMask = rgbMask / 2;

  if ( rHigh == 1 )
    digitalWrite(lred,   HIGH);
  else
    digitalWrite(lred,   LOW);

  if ( gHigh == 1 )
    digitalWrite(lgreen, HIGH);
  else
    digitalWrite(lgreen, LOW);

  if ( bHigh == 1 )
    digitalWrite(lblue,  HIGH);
  else
    digitalWrite(lblue,  LOW);

  delay(on);                  // Wait for it!

  if ( on >= cycle ) {
    delay( 1000 );
  }

  rgbMask = lowMask;

  int rLow = rgbMask % 2;
  rgbMask = rgbMask / 2;

  int gLow = rgbMask % 2;
  rgbMask = rgbMask / 2;

  int bLow = rgbMask % 2;
  rgbMask = rgbMask / 2;

  if ( rLow == 1 )
    digitalWrite(lred,   HIGH);
  else
    digitalWrite(lred,   LOW);

  if ( gLow == 1 )
    digitalWrite(lgreen, HIGH);
  else
    digitalWrite(lgreen, LOW);

  if ( bLow == 1 )
    digitalWrite(lblue,  HIGH);
  else
    digitalWrite(lblue,  LOW);

  delay(cycle - on);          // Wait for it!

}