/*
   game/ship.cc
   This file is part of the Osirion project and is distributed under 
   the terms and conditions of the GNU General Public License version 2 
*/

// project headers
#include "game/ship.h"
#include "math/mathlib.h"

// C++ headers
#include <iostream>

using math::degrees360f;
using math::degrees180f;

namespace game {

Ship::Ship()
{
	speed = 0;
	yaw_current = 0;
	yaw_target = yaw_current;

	thrust_current = 0;
	
	// ship specs
	acceleration = 1.5f;
	speed_max = 4.0f;
	yaw_speed = 4.0f;
}

Ship::~Ship() 
{
}

void Ship::set_yaw(float y) 
{
	yaw_target = degrees360f(y);
}

void Ship::set_thrust(float t)
{
	if (t < 0)
		thrust_current = 0;
	else if (t > 1)
		thrust_current = 1;
	else
		thrust_current = t;
}

void Ship::update(float elapsed) 
{
	// update yaw
	float yaw_offset = degrees180f(yaw_target - yaw_current);
	float d = yaw_speed * elapsed * yaw_offset;
	yaw_current = degrees360f(yaw_current + d);

	// update thrust
	if (speed < thrust_current * speed_max) {
		speed += acceleration * elapsed;
		if (speed > thrust_current * speed_max) {
			speed = thrust_current * speed_max;
		}
	} else if(speed > thrust_current * speed_max) {
		speed -= acceleration * elapsed;
		if (speed < 0) speed = 0;
	}

	// location TODO avoid sin/cos calculations
	location.x += cosf(yaw_current * M_PI / 180) * speed * elapsed;
	location.z -= sinf(yaw_current * M_PI / 180) * speed * elapsed;
}

} // namespace game