In this chapter, we discussed the history of physics in computer games, and how that history dates back to the very first computer game, SpaceWar!. We talked about the physics that we already have in our game, which includes the conservation of momentum. We briefly discussed Newton's third law and how it applies to games, and we then added more Newtonian physics to our game by using the third law. We added a gravitational field to our star and had it attract the spaceships in our game with a force that decreases with the square of the distance between the two objects. Finally, we added elastic collisions between our spaceships, projectiles, and asteroids.
In the next chapter, we will add a user interface (UI) to our game. We will also break the game up into multiple screens and add a mouse interface.