Box2D
2.4.1
A 2D physics engine for games

#include <b2_collision.h>
Public Types  
enum  Type { e_circles, e_faceA, e_faceB } 
Public Attributes  
b2ManifoldPoint  points [b2_maxManifoldPoints] 
the points of contact  
b2Vec2  localNormal 
not use for Type::e_points  
b2Vec2  localPoint 
usage depends on manifold type  
Type  type 
int32  pointCount 
the number of manifold points  
A manifold for two touching convex shapes. Box2D supports multiple types of contact: