Farseer Physics Engine

Farseer Physics Engine 是个好东西，虽然比较简单，但功能完整。

正在学习和分析这个简单例子

Farseer 物理引擎的主要功能有：

* Continuous collision detection (with time of impact solver)

* Contact callbacks: begin, end, pre-solve, post-solve

* Convex polyons and circles.

* Multiple shapes per body

* Dynamic tree broadphase

* Fast broadphase AABB queries

* Collision groups and categories

* Sleep management

* Contact, friction, and restitution

* Stable stacking with a linear-time solver

* Revolute, prismatic, distance, pulley, gear, mouse joint, and other joint types

* Joint limits, motors, and friction

* Controllers (gravity, force generators)

* Tools to decompose concave polygons, find convex hulls, boolean operations and more.