b2Manifold Struct Reference

#include <b2Collision.h>

Collaboration diagram for b2Manifold:

List of all members.

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

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Detailed Description

A manifold for two touching convex shapes. Box2D supports multiple types of contact:

• clip point versus plane with radius
• point versus point with radius (circles) The local point usage depends on the manifold type: -e_circles: the local center of circleA -e_faceA: the center of faceA -e_faceB: the center of faceB Similarly the local normal usage: -e_circles: not used -e_faceA: the normal on polygonA -e_faceB: the normal on polygonB We store contacts in this way so that position correction can account for movement, which is critical for continuous physics. All contact scenarios must be expressed in one of these types. This structure is stored across time steps, so we keep it small.

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Member Data Documentation

b2Vec2 b2Manifold::localNormal

not use for Type::e_points

b2Vec2 b2Manifold::localPoint

usage depends on manifold type

int32 b2Manifold::pointCount

the number of manifold points

b2ManifoldPoint b2Manifold::points[b2_maxManifoldPoints]

the points of contact

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The documentation for this struct was generated from the following file:

• b2Collision.h