====== HoverEX : Physics Engine ======
The physcis engine in HoverEX uses the prediction step size model. This means that the calculation step depends on the collision time of any single object or any few objects. The engine first looks for the shortest interval of a possible collision between the given time step. It then move all objects to the particular time step and execute the physical reaction of those colliding objects. After that, it does a check again and see if there are any possible collision between the given deducted time step. This goes on until there is no collision between the given deducted time step. It then just simply move all objects using the remaining time step.

As Circle <=> Line collision is very expensive, the BSP engine was introduced to cut down the number of collision line to test for each objects. This improve the performance quite abit when having alot of objects flying about.

Bellow links to various detailed description of how the Physics Engine works.
  * [[Basic Physics]]
  * [[Hovercraft Motion Simulation]]
  * [[Collision Detection]]

====== References ======

===== Basic Physics =====
  * [[http://en.wikipedia.org/wiki/Vector_%28spatial%29|Vector]]
  * [[http://en.wikipedia.org/wiki/Force_%28physics%29|Force]]
  * [[http://en.wikipedia.org/wiki/Thrust|Thrust]]
  * [[http://en.wikipedia.org/wiki/Friction|Friction]]
  * [[http://en.wikipedia.org/wiki/Momentum|Momentum]]
  * [[http://en.wikipedia.org/wiki/Impulse|Impulse]]

===== Drag Force =====
  * [[http://en.wikipedia.org/wiki/Atmospheric_drag|Drag]]
  * [[http://en.wikipedia.org/wiki/Drag_coefficient|Drag Coefficient]]
  * [[http://en.wikipedia.org/wiki/Density|Density]]

===== Game Physics =====
  * [[http://www.gaffer.org/articles/|Very decent articles about physics simulation in games by Gaffer]]