fx.cpp

/*
 *  fx.cpp
 *  kattMickisShooter
 *
 *  Created by Erik Andersson on 2009-12-13.
 *  Copyright (c) 2010 Erik Andersson
 *
 *  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 <iostream>
#include "SDL.h"

#include "fx.h"

Fx::Fx(double(*trans)(double)): _transition(trans), _is_running(false)
{

}

void Fx::start()
{
	_start_time = SDL_GetTicks();
	_is_running = true;
}

double Fx::step()
{
	Uint32 time = SDL_GetTicks();
	double time_delta = (time - _start_time) / _duration;
	if ( _mode == Tween )
	{
		if ( time_delta >= 1 )
		{
			stop();
			return _to;
		}
		double delta = _transition(time_delta);
		return (_to - _from) * delta + _from;
	}
	else if ( _mode == Single )
	{
		if ( time_delta >= 1 )
		{
			stop();
			return _value * _transition(1);
		}
		return _value * _transition(time_delta);
	}
	return -1;
}

void Fx::stop()
{
	_is_running = false;
}

/*void foo()
{
	Fx anim(Fx::pow);
	anim.value(100, 200);
	anim.duration(500);

	anim.start();
	double value = anim.step();

	std::cout << value << std::endl;
}*/