planck

# Class: GearJoint A gear joint is used to connect two joints together. Either joint can be a revolute or prismatic joint. You specify a gear ratio to bind the motions together: coordinate1 + ratio * coordinate2 = constant The ratio can be negative or positive. If one joint is a revolute joint and the other joint is a prismatic joint, then the ratio will have units of length or units of 1/length. Warning: You have to manually destroy the gear joint if joint1 or joint2 is destroyed. This definition requires two existing revolute or prismatic joints (any combination will work). ## Extends - [`Joint`](/api/classes/Joint) ## Constructors ### new GearJoint() > **new GearJoint**(`def`): [`GearJoint`](/api/classes/GearJoint) #### Parameters • **def**: [`GearJointDef`](/api/interfaces/GearJointDef) #### Returns [`GearJoint`](/api/classes/GearJoint) #### Overrides [`Joint`](/api/classes/Joint).[`constructor`](/api/classes/Joint#constructors) ### new GearJoint() > **new GearJoint**(`def`, `bodyA`, `bodyB`, `joint1`, `joint2`, `ratio`?): [`GearJoint`](/api/classes/GearJoint) #### Parameters • **def**: [`GearJointOpt`](/api/interfaces/GearJointOpt) • **bodyA**: [`Body`](/api/classes/Body) • **bodyB**: [`Body`](/api/classes/Body) • **joint1**: [`RevoluteJoint`](/api/classes/RevoluteJoint) \| [`PrismaticJoint`](/api/classes/PrismaticJoint) • **joint2**: [`RevoluteJoint`](/api/classes/RevoluteJoint) \| [`PrismaticJoint`](/api/classes/PrismaticJoint) • **ratio?**: `number` #### Returns [`GearJoint`](/api/classes/GearJoint) #### Overrides [`Joint`](/api/classes/Joint).[`constructor`](/api/classes/Joint#constructors) ## Properties ### style > **style**: [`Style`](/api/interfaces/Style) = `{}` Styling for dev-tools. #### Inherited from [`Joint`](/api/classes/Joint).[`style`](/api/classes/Joint#style) *** ### TYPE > `static` **TYPE**: `"gear-joint"` ## Methods ### getAnchorA() > **getAnchorA**(): [`Vec2`](/api/classes/Vec2) Get the anchor point on bodyA in world coordinates. #### Returns [`Vec2`](/api/classes/Vec2) #### Overrides [`Joint`](/api/classes/Joint).[`getAnchorA`](/api/classes/Joint#getanchora) *** ### getAnchorB() > **getAnchorB**(): [`Vec2`](/api/classes/Vec2) Get the anchor point on bodyB in world coordinates. #### Returns [`Vec2`](/api/classes/Vec2) #### Overrides [`Joint`](/api/classes/Joint).[`getAnchorB`](/api/classes/Joint#getanchorb) *** ### getBodyA() > **getBodyA**(): [`Body`](/api/classes/Body) Get the first body attached to this joint. #### Returns [`Body`](/api/classes/Body) #### Inherited from [`Joint`](/api/classes/Joint).[`getBodyA`](/api/classes/Joint#getbodya) *** ### getBodyB() > **getBodyB**(): [`Body`](/api/classes/Body) Get the second body attached to this joint. #### Returns [`Body`](/api/classes/Body) #### Inherited from [`Joint`](/api/classes/Joint).[`getBodyB`](/api/classes/Joint#getbodyb) *** ### getCollideConnected() > **getCollideConnected**(): `boolean` Get collide connected. Note: modifying the collide connect flag won't work correctly because the flag is only checked when fixture AABBs begin to overlap. #### Returns `boolean` #### Inherited from [`Joint`](/api/classes/Joint).[`getCollideConnected`](/api/classes/Joint#getcollideconnected) *** ### getJoint1() > **getJoint1**(): [`Joint`](/api/classes/Joint) Get the first joint. #### Returns [`Joint`](/api/classes/Joint) *** ### getJoint2() > **getJoint2**(): [`Joint`](/api/classes/Joint) Get the second joint. #### Returns [`Joint`](/api/classes/Joint) *** ### getNext() > **getNext**(): [`Joint`](/api/classes/Joint) Get the next joint the world joint list. #### Returns [`Joint`](/api/classes/Joint) #### Inherited from [`Joint`](/api/classes/Joint).[`getNext`](/api/classes/Joint#getnext) *** ### getRatio() > **getRatio**(): `number` Get the gear ratio. #### Returns `number` *** ### getReactionForce() > **getReactionForce**(`inv_dt`): [`Vec2`](/api/classes/Vec2) Get the reaction force on bodyB at the joint anchor in Newtons. #### Parameters • **inv\_dt**: `number` #### Returns [`Vec2`](/api/classes/Vec2) #### Overrides [`Joint`](/api/classes/Joint).[`getReactionForce`](/api/classes/Joint#getreactionforce) *** ### getReactionTorque() > **getReactionTorque**(`inv_dt`): `number` Get the reaction torque on bodyB in N*m. #### Parameters • **inv\_dt**: `number` #### Returns `number` #### Overrides [`Joint`](/api/classes/Joint).[`getReactionTorque`](/api/classes/Joint#getreactiontorque) *** ### getType() > **getType**(): `string` Get the type of the concrete joint. #### Returns `string` #### Inherited from [`Joint`](/api/classes/Joint).[`getType`](/api/classes/Joint#gettype) *** ### getUserData() > **getUserData**(): `unknown` #### Returns `unknown` #### Inherited from [`Joint`](/api/classes/Joint).[`getUserData`](/api/classes/Joint#getuserdata) *** ### initVelocityConstraints() > **initVelocityConstraints**(`step`): `void` #### Parameters • **step**: [`TimeStep`](/api/classes/TimeStep) #### Returns `void` #### Overrides [`Joint`](/api/classes/Joint).[`initVelocityConstraints`](/api/classes/Joint#initvelocityconstraints) *** ### isActive() > **isActive**(): `boolean` Short-cut function to determine if either body is inactive. #### Returns `boolean` #### Inherited from [`Joint`](/api/classes/Joint).[`isActive`](/api/classes/Joint#isactive) *** ### setRatio() > **setRatio**(`ratio`): `void` Set the gear ratio. #### Parameters • **ratio**: `number` #### Returns `void` *** ### setUserData() > **setUserData**(`data`): `void` #### Parameters • **data**: `unknown` #### Returns `void` #### Inherited from [`Joint`](/api/classes/Joint).[`setUserData`](/api/classes/Joint#setuserdata) *** ### shiftOrigin() > **shiftOrigin**(`newOrigin`): `void` Shift the origin for any points stored in world coordinates. #### Parameters • **newOrigin**: [`Vec2Value`](/api/interfaces/Vec2Value) #### Returns `void` #### Inherited from [`Joint`](/api/classes/Joint).[`shiftOrigin`](/api/classes/Joint#shiftorigin) *** ### solvePositionConstraints() > **solvePositionConstraints**(`step`): `boolean` This returns true if the position errors are within tolerance. #### Parameters • **step**: [`TimeStep`](/api/classes/TimeStep) #### Returns `boolean` #### Overrides [`Joint`](/api/classes/Joint).[`solvePositionConstraints`](/api/classes/Joint#solvepositionconstraints) *** ### solveVelocityConstraints() > **solveVelocityConstraints**(`step`): `void` #### Parameters • **step**: [`TimeStep`](/api/classes/TimeStep) #### Returns `void` #### Overrides [`Joint`](/api/classes/Joint).[`solveVelocityConstraints`](/api/classes/Joint#solvevelocityconstraints)