Light mixer with output RGB values

int red;  
int green;
int blue;
int fade_red;
int fade_green;
int fade_blue;
int fade_up;
int fade_down;
// Anything defined in the space _above_ setup() is GLOBAL. 
// A global // variable can be used in both the setup() and loop() functions. 
// We'll want to use fade in both of those functions.

void setup()
{
  Serial.begin(9600);
  Serial.println("Color Mixing!");

  pinMode(9, OUTPUT); 
  pinMode(10, OUTPUT);  
  pinMode(11, OUTPUT);  
  
  red = 0;  
  green = 60;
  blue = 120;
  fade_red = 5;
  fade_green = 5;
  fade_blue = 5;
  fade_up = 5;
  fade_down = -5;
}

void loop()
{
  if (digitalRead(12) == HIGH)
  {
  }
  else 
  {
    analogWrite(9, red);
    analogWrite(10, green);
    analogWrite(11, blue);
    red = red + fade_red; // Increment fade by 1
    green = green + fade_green; // Increment fade by 1
    blue = blue + fade_blue;  // Increment fade by 1
    Serial.print(red);
    Serial.print(", ");
    Serial.print(green);
    Serial.print(", ");
    Serial.print(blue);
    Serial.println();
    if (red > 180)
      fade_red = fade_down;
    if (green > 180)
      fade_green = fade_down;
    if (blue > 180)
      fade_blue = fade_down;
    if (red < 10)
      fade_red = fade_up;
    if (green < 10)
      fade_green = fade_up;
    if (blue < 10)
      fade_blue = fade_up;
    delay(100); // Wait half a second
  }
}