Sample vehicle handling in SFML

VehicleExample

/*********************************************************************
Example code to accompany article at:

http://trederia.blogspot.com/2014/02/space-racers-breakdown-part-3-vehicle.html


*********************************************************************/

#include <SFML/System.hpp>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>

#include <Helpers.h>

#include <sstream>

int main()
{
	sf::RenderWindow renderWindow(sf::VideoMode(800u, 600u), "Vehicle Handling");
	sf::Clock deltaClock, frameClock;
	//set up visual for vehicle
	sf::RectangleShape car(sf::Vector2f(10.f, 30.f));
	car.setOrigin(5.f ,15.f);
	car.setPosition(400.f, 300.f);
	//some movement values
	sf::Vector2f movementVec; //normal vector based on current direction
	const sf::Vector2f forwardVec(0.f, 1.f); //normal vec pointing forward
	float currentSpeed = 0.f;
	//consts are units per second as each value is multiplied by frame time
	const float acceleration = 360.f;
	const float deceleration = 250.f;
	const float maxSpeed = 800.f;
	const float rotateAmount = 245.f;


	//-----------------------------------//

	while(renderWindow.isOpen())
	{
		//poll input
		sf::Event event;
		while(renderWindow.pollEvent(event))
		{
			if (event.type == sf::Event::Closed
				|| (event.type == sf::Event::KeyPressed && event.key.code == sf::Keyboard::Escape))
				renderWindow.close();
        }

		//------------------------
		float dt = deltaClock.restart().asSeconds();

		//set speed and direction from keyboard input
		if(sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
			car.rotate(-rotateAmount *dt);
		else if(sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
			car.rotate(rotateAmount * dt);

		if(sf::Keyboard::isKeyPressed(sf::Keyboard::Up))
		{
			if(currentSpeed < maxSpeed)
			{
				currentSpeed += acceleration * dt;
			}

			//rotate direction vector
			sf::Vector2f oldVec = movementVec;
			sf::Transform t;
			t.rotate(car.getRotation());
			movementVec = t.transformPoint(forwardVec);
			//calc the dot product so any rotation reduces the
			//current speed - gives the impression of wheel spin
			//when accelerating after a tight turn
			currentSpeed *= Helpers::Vectors::Dot(oldVec, movementVec);
		}
		else
		{
			currentSpeed -= deceleration * dt;
			if(currentSpeed < 0.f) currentSpeed = 0.f;
		}



		//finally, move car
		car.move(movementVec * currentSpeed * dt);

		//-------draw-------------
		frameClock.restart();

		renderWindow.clear();
		renderWindow.draw(car);
		renderWindow.display();



		//----------------------
		const float time = 1.f / frameClock.getElapsedTime().asSeconds();
		std::stringstream stream;
		stream << "Current fps: " << time << std::endl;
		renderWindow.setTitle(stream.str());
	}

	return 0;
}