Box2D: b2Contact Class Reference

| Box2D 2.4.1 A 2D physics engine for games

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Public Member Functions | Protected Types | Protected Member Functions | Static Protected Member Functions | Protected Attributes | Static Protected Attributes | Friends | List of all members
b2Contact Class Referenceabstract

`#include <b2_contact.h>`

## Public Member Functions
b2Manifold * | GetManifold ()
const b2Manifold * | GetManifold () const
void | GetWorldManifold (b2WorldManifold *worldManifold) const
| Get the world manifold.
bool | IsTouching () const
| Is this contact touching?
void | SetEnabled (bool flag)
bool | IsEnabled () const
| Has this contact been disabled?
b2Contact * | GetNext ()
| Get the next contact in the world's contact list.
const b2Contact * | GetNext () const
b2Fixture * | GetFixtureA ()
| Get fixture A in this contact.
const b2Fixture * | GetFixtureA () const
int32 | GetChildIndexA () const
| Get the child primitive index for fixture A.
b2Fixture * | GetFixtureB ()
| Get fixture B in this contact.
const b2Fixture * | GetFixtureB () const
int32 | GetChildIndexB () const
| Get the child primitive index for fixture B.
void | SetFriction (float friction)
float | GetFriction () const
| Get the friction.
void | ResetFriction ()
| Reset the friction mixture to the default value.
void | SetRestitution (float restitution)
float | GetRestitution () const
| Get the restitution.
void | ResetRestitution ()
| Reset the restitution to the default value.
void | SetRestitutionThreshold (float threshold)
float | GetRestitutionThreshold () const
| Get the restitution threshold.
void | ResetRestitutionThreshold ()
| Reset the restitution threshold to the default value.
void | SetTangentSpeed (float speed)
| Set the desired tangent speed for a conveyor belt behavior. In meters per second.
float | GetTangentSpeed () const
| Get the desired tangent speed. In meters per second.
virtual void | Evaluate (b2Manifold *manifold, const b2Transform &xfA, const b2Transform &xfB)=0
| Evaluate this contact with your own manifold and transforms.

## Protected Types
enum | { e_islandFlag = 0x0001 , e_touchingFlag = 0x0002 , e_enabledFlag = 0x0004 , e_filterFlag = 0x0008 , e_bulletHitFlag = 0x0010 , e_toiFlag = 0x0020 }

## Protected Member Functions
void | FlagForFiltering ()
| Flag this contact for filtering. Filtering will occur the next time step.
| b2Contact (b2Fixture *fixtureA, int32 indexA, b2Fixture *fixtureB, int32 indexB)
void | Update (b2ContactListener *listener)

## Static Protected Member Functions
static void | AddType (b2ContactCreateFcn *createFcn, b2ContactDestroyFcn *destroyFcn, b2Shape::Type typeA, b2Shape::Type typeB)
static void | InitializeRegisters ()
static b2Contact * | Create (b2Fixture *fixtureA, int32 indexA, b2Fixture *fixtureB, int32 indexB, b2BlockAllocator *allocator)
static void | Destroy (b2Contact *contact, b2Shape::Type typeA, b2Shape::Type typeB, b2BlockAllocator *allocator)
static void | Destroy (b2Contact *contact, b2BlockAllocator *allocator)

## Protected Attributes
uint32 | m_flags
b2Contact * | m_prev
b2Contact * | m_next
b2ContactEdge | m_nodeA
b2ContactEdge | m_nodeB
b2Fixture * | m_fixtureA
b2Fixture * | m_fixtureB
int32 | m_indexA
int32 | m_indexB
b2Manifold | m_manifold
int32 | m_toiCount
float | m_toi
float | m_friction
float | m_restitution
float | m_restitutionThreshold
float | m_tangentSpeed

## Static Protected Attributes
static b2ContactRegister | s_registers [b2Shape::e_typeCount][b2Shape::e_typeCount]
static bool | s_initialized

## Friends
class | b2ContactManager
class | b2World
class | b2ContactSolver
class | b2Body
class | b2Fixture

## Detailed Description

The class manages contact between two shapes. A contact exists for each overlapping AABB in the broad-phase (except if filtered). Therefore a contact object may exist that has no contact points.

## Member Function Documentation

## ◆ GetManifold()

b2Manifold * b2Contact::GetManifold | ( |  | ) |
| inline

Get the contact manifold. Do not modify the manifold unless you understand the internals of Box2D.

## ◆ SetEnabled()

void b2Contact::SetEnabled | ( | bool | flag | ) |
| inline

Enable/disable this contact. This can be used inside the pre-solve contact listener. The contact is only disabled for the current time step (or sub-step in continuous collisions).

## ◆ SetFriction()

void b2Contact::SetFriction | ( | float | friction | ) |
| inline

Override the default friction mixture. You can call this in b2ContactListener::PreSolve. This value persists until set or reset.

## ◆ SetRestitution()

void b2Contact::SetRestitution | ( | float | restitution | ) |
| inline

Override the default restitution mixture. You can call this in b2ContactListener::PreSolve. The value persists until you set or reset.

## ◆ SetRestitutionThreshold()

void b2Contact::SetRestitutionThreshold | ( | float | threshold | ) |
| inline

Override the default restitution velocity threshold mixture. You can call this in b2ContactListener::PreSolve. The value persists until you set or reset.

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

- /build/box2d/src/box2d-2.4.2/include/box2d/b2_contact.h