ChaseLEDs.cpp

/*
 * Copyright (C) 2012 Southern Storm Software, Pty Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "ChaseLEDs.h"
#if defined(ARDUINO) && ARDUINO >= 100
#include <Arduino.h>
#else
#include <WProgram.h>
#endif

ChaseLEDs::ChaseLEDs(const uint8_t *pins, int num, unsigned long advanceTime)
    : _pins(pins)
    , _numPins(num)
    , _currentIndex(-1)
    , _advanceTime(advanceTime)
    , _lastChange(millis())
{
    for (uint8_t index = 0; index < _numPins; ++index) {
        pinMode(_pins[index], OUTPUT);
        digitalWrite(_pins[index], LOW);
    }
}

void ChaseLEDs::loop()
{
    if (_currentIndex >= 0) {
        if ((millis() - _lastChange) >= _advanceTime) {
            // Advance to the next LED in sequence.
            _currentIndex = (_currentIndex + 1) % _numPins;
            _lastChange += _advanceTime;
            advance(previousPin(1), _pins[_currentIndex]);
        }
    } else {
        // First time - light the first LED.
        _currentIndex = 0;
        _lastChange = millis();
        advance(previousPin(1), _pins[_currentIndex]);
    }
}

void ChaseLEDs::advance(uint8_t prevPin, uint8_t nextPin)
{
    digitalWrite(prevPin, LOW);
    digitalWrite(nextPin, HIGH);
}