Jeffrey T. Palmer > Box2D-0.07 > Box2D::b2FrictionJoint

# NAME

Box2D::b2FrictionJoint - Provides translational and angular friction.

# SYNOPSIS

```  my \$joint = \$world->CreateJoint( \$joint_def );
\$joint->SetMaxForce( \$max_force );
\$joint->SetMaxTorque( \$max_torque );```

# DESCRIPTION

Friction joint. This is used for top-down friction. It provides 2D translational friction and angular friction.

# METHODS

## GetAnchorA()

Get the anchor point on bodyA in world coordinates. Implements `Box2D::b2Joint`.

Returns a `Box2D::b2Vec2`

## GetAnchorB()

Get the anchor point on bodyB in world coordinates. Implements `Box2D::b2Joint`.

Returns a `Box2D::b2Vec2`

## GetMaxForce()

Get the maximum friction force in N.

Returns a `float32`

## GetMaxTorque()

Get the maximum friction torque in N*m.

Returns a `float32`

## GetReactionForce( \$inv_dt )

Get the reaction force on body2 at the joint anchor in Newtons. Implements `Box2D::b2Joint`.

Parameters:

• `float32` `\$inv_dt`

Returns a `Box2D::b2Vec2`

## GetReactionTorque( \$inv_dt )

Get the reaction torque on body2 in N*m. Implements `Box2D::b2Joint`.

Parameters:

• `float32` `\$inv_dt`

Returns a `float32`

## SetMaxForce( \$force )

Set the maximum friction force in N.

Parameters:

• `float32` `\$force`

## SetMaxTorque( \$torque )

Set the maximum friction torque in N*m.

Parameters:

• `float32` `\$torque`