Newtonian Physics

I love physics. When I was in high school, I didn’t. I liked the theory but found the math confusing largely because I had a very poor math teacher who failed to properly teach me the necessary math knowledge to properly appreciate the math that makes up physics. One of the biggest failings of education is that a lot of teachers want to teach the how and not the why when to truly understand a subject, the why is the important part. When I started properly playing around with computer graphics and had to learn the why of trigonometry, I gained a far greater appreciation for it.

Physics is one of those subjects that actually can be much more greatly appreciated once you actually start using some of the concepts in your programs, it becomes a wonderful subject. The thing to always remember is that you are creating a simulation. You do not need to use the proper formulas and functions as often approximations will do just as well. I believe it was John Carmack who said, “If you break a problem into thin enough slices time-wise, you do not need to use elaborate math but can instead to resort to much simpler and faster linear algebra.”

The game revolves around two of Newton’s laws of Motion. The first being “Objects in motion stay in motion while objects at rest stay at rest unless a force is applied to that object.” The second law is simply “For every action there is an equal but opposite reaction”.

This essentially means that once an object starts moving, it will continue moving until a new force is applied. When the new force is applied, it is added to the existing force. Adding two opposite but equal forces causes the object to stop. Essentially, you are adding a number of motion vectors together to get the current speed and direction.

When an object hits another object, the motion vector of both objects are adjusted. How much of an effect this has is dependent on the mass and speed of the respective objects. While a space ship crashing into a space station wall will cause the space station to move, the vast difference in the mass of the two objects makes the amount of motion extremely small. The wonderful thing about this is that the amount is so small it can be ignored. More so, bumping into a wall is deadly, so we don’t even have to worry about calculating the adjusted motion to the space ship. This, however, is something that could be done if desired.