Game Development Reference
In-Depth Information
So what is a physics engine?
The famous Isaac Newton said,
every action has a reaction
. Right after he said,
who the
hell threw that apple?
So far in our games, we have covered very simple collision systems, basically only ever
checking to see if simple shapes (circles and rectangles) overlapped each other. The reac-
tions from these collisions were also very simple in our games so far: with vector inver-
sions or simply by making things disappear once they touch. With Box2D, you get way
more!
Box2D is a very robust collision detection engine and can certainly be used just for that
purpose. But the simulation will also process and return a bunch of information derived
from the collisions and the interactions between bodies, meaning how the objects should
behave, based on their shapes, mass, and all the forces at play in the simulation.
