Code for adding joystick support to the Gameduino Frogger game.

frogger.pde

class Controller {
  public:
    void begin() {
      byte i;
      for (i = 3; i < 7; i++) {
        pinMode(i, INPUT);
        digitalWrite(i, HIGH);
      }
      prev = 0;
    }
    byte read() {
      int x = analogRead(0);
      int y = analogRead(1);
      byte r = 0;
      if (!digitalRead(5) || y==0)
        r |= CONTROL_DOWN;
      if (!digitalRead(4) || y==1023)
        r |= CONTROL_UP;
      if (!digitalRead(6) || x==0)
        r |= CONTROL_LEFT;
      if (!digitalRead(3) || x==1023)
        r |= CONTROL_RIGHT;
      byte edge = r & ~prev;
      prev = r;
      return edge;
    }
  private:
    byte prev;
};