/*
 * 30 Days - Lost in Space
 * Day 8 - Adding some color to this dark place
 *
 * Learn more at https://inventr.io/adventure
 *
 * Previously we have used different color LEDs with our HERO, but when we require
 * more output, or desire a color different from the available colors we use a more
 * flexible "RGB LED".  RGB LEDs have a red, a green and a blue LED packaged into a
 * single LED package.  By using something called Pulse Width Modulation (PWM) we
 * can vary the intensity of each LED and come up a wide variety of colors.
 *
 * Alex Eschenauer
 * David Schmidt
 * Greg Lyzenga
 */
 
/*
 * Arduino concepts introduced/documented in this lesson.
 * - analogWrite(): Used to control a PWM pin, giving a variable intensity
 * - Passing variables into functions
 *
 * Parts and electronics concepts introduced in this lesson.
 * - Common Cathode (single grounded pin) RGB LED.
 */

// Explicitly include Arduino.h
#include "Arduino.h"

/*
 * Each color in an RGB LED is controlled with a different pin on our HERO board.
 *
 * NOTE: Only pins 3, 5, 6, 9, 10 and 11 on the HERO board support PWM which is
 *       indicated on the board by preceding those pin numbers on the HERO board
 *       with a tilde ('~') character.  Only those pins support PWM and analogWrite().
 */
const byte RED_PIN = 11;    // PWM pin controlling the red leg of our RGB LED
const byte GREEN_PIN = 10;  // PWM pin ccontrolling the green leg of our RGB LED
const byte BLUE_PIN = 9;    // PWM pin ccontrolling the blue leg of our RGB LED

/*
 * Define a set of constants to represent 4 different brightness levels for our
 * RGB LED using PWM pins and analogWrite().  PWM can set values ranging from 0
 * to 255 which we will demonstrate by adding 64 (roughly 1/4 of that range) to
 * each preceding value.
 *
 * NOTE: this also demonstrates that our constants can be computed using an expression
 *       that includes any previouly defined constant.  However, the expression cannot
 *       include variables or values that could change during execution.
 */
const byte OFF = 0;                 // Selected color is OFF
const byte DIM = 64;                // Selected color is 1/4 intensity
const byte BRIGHTER = DIM + 64;     // Selected color is 1/2 intensity
const byte BRIGHT = BRIGHTER + 64;  // Selected color is 3/4 intensity
const byte BRIGHTEST = 255;         // Selected color is maximum intensity (255)

// We can change this constant here, in one place, to change how long each color is displayed.
const unsigned int COLOR_DELAY = 1000;  // show each color for 500 milliseconds

void setup() {
  // Set each of our PWM pins as OUTPUT pins
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);
  Serial.begin(9600);
}

// Each time through loop() we display some of the color variations available
// using an RGB LED.
void loop() {
  // First demonstrate our different PWM levels by slowly brightening our red LED

  for (int x = 0; x < 255; x=x+63) {
    for (int y = 0; y < 255; y=y+63) {
      for (int z = 0; z < 255; z=z+63) {
        displayColor(x,y,z);
        delay(COLOR_DELAY);
      }

    }
  }
 
}

/*
 * displayColor() is a function that accepts three parameters representing the desired
 * intensity for each of the LEDs in the RGB LED.
 *
 * Each parameter passed must have a type (here we match what analogWrite() will use) and
 * a name to be used inside the function to refer to the parameter.  The parameters can all
 * be included on a single line like:
 * void displayColor( byte red_intensity, byte green_intensity, byte blue_intensity) {
 * 
 * However, if we display each parameter on it's own line we can add a comment to each
 * for additional clarity.
 */
void displayColor(
  byte red_intensity,    // red LED intensity (0-255)
  byte green_intensity,  // green LED intensity (0-255)
  byte blue_intensity    // blue LED intensity (0-255)
) {
  analogWrite(RED_PIN, red_intensity);      // Set red LED intensity using PWM
  analogWrite(GREEN_PIN, green_intensity);  // Set green LED intensity using PWM
  analogWrite(BLUE_PIN, blue_intensity);    // Set blue LED intensity using PWM
}