Class: PivotConstraint

physics/constraints/pivot.PivotConstraint

Represents a pivot joint between two CollisionObjects or a CollisionObject and a point.

This constraint will keep the object's joined together by their anchor points at the given point.

Hierarchy

• Constraint

  ↳ PivotConstraint

  ↳↳ MouseConstraint

  ↳↳ TouchConstraint

Constructors

constructor

• new PivotConstraint(a, b, point)

Creates a new PivotConstraint between two bodies.

Parameters

Name	Type	Description
a	CollisionObject	The first body
b	CollisionObject	The second body
point	vec2	The point to join the bodies at in world space

Overrides

Constraint.constructor

Defined in

src/physics/constraints/pivot.ts:29

• new PivotConstraint(opts)

Creates a new PivotConstraint with the given options.

Parameters

Name	Type	Description
opts	PivotConstraintOptions	The constraint options

Overrides

Constraint.constructor

Defined in

src/physics/constraints/pivot.ts:36

• new PivotConstraint(a, point)

Creates a new PivotConstraint between a body and a point.

Parameters

Name	Type	Description
a	CollisionObject	The body to constrain
point	vec2	A point in world space

Overrides

Constraint.constructor

Defined in

src/physics/constraints/pivot.ts:44

Properties

a

• a: CollisionObject

Inherited from

Constraint.a

Defined in

src/physics/constraints/constraint.ts:22

---

anchorA

• anchorA: vec2

Inherited from

Constraint.anchorA

Defined in

src/physics/constraints/constraint.ts:23

---

anchorB

• anchorB: vec2

Inherited from

Constraint.anchorB

Defined in

src/physics/constraints/constraint.ts:27

---

b

• b: CollisionObject

Inherited from

Constraint.b

Defined in

src/physics/constraints/constraint.ts:26

---

bias

• bias: vec2

Defined in

src/physics/constraints/pivot.ts:18

---

errorBias

• errorBias: number

Inherited from

Constraint.errorBias

Defined in

src/physics/constraints/constraint.ts:32

---

jAcc

• jAcc: vec2

Defined in

src/physics/constraints/pivot.ts:19

---

k

• k: mat2

Defined in

src/physics/constraints/pivot.ts:20

---

maxBias

• maxBias: number = Infinity

Inherited from

Constraint.maxBias

Defined in

src/physics/constraints/constraint.ts:33

---

maxForce

• maxForce: number = Infinity

Inherited from

Constraint.maxForce

Defined in

src/physics/constraints/constraint.ts:35

---

point

• point: vec2

Inherited from

Constraint.point

Defined in

src/physics/constraints/constraint.ts:30

---

rotA

• rotA: number = 0

Inherited from

Constraint.rotA

Defined in

src/physics/constraints/constraint.ts:24

---

rotB

• rotB: number = 0

Inherited from

Constraint.rotB

Defined in

src/physics/constraints/constraint.ts:28

Methods

applyImpulses

▸ Protected applyImpulses(impulse, direction): void

Parameters

Name	Type
impulse	number
direction	vec2

Returns

void

Inherited from

Constraint.applyImpulses

Defined in

src/physics/constraints/constraint.ts:111

▸ Protected applyImpulses(impulse): void

Parameters

Name	Type
impulse	vec2

Returns

void

Inherited from

Constraint.applyImpulses

Defined in

src/physics/constraints/constraint.ts:113

---

biasCoef

▸ Protected biasCoef(dt): number

Calculates the velocity bias coefficient.

Parameters

Name	Type	Description
dt	number	The time since the last update

Returns

number

Inherited from

Constraint.biasCoef

Defined in

src/physics/constraints/constraint.ts:182

---

calculateRelativeVelocity

▸ Protected calculateRelativeVelocity(pointA, pointB): vec2

Calculate the relative velocity of the bodies in the constraint.

Parameters

Name	Type	Description
pointA	vec2	The anchor point on body a
pointB	vec2	The anchor point on body b

Returns

vec2

The relative velocity between body a and b or body a and the anchor point

Inherited from

Constraint.calculateRelativeVelocity

Defined in

src/physics/constraints/constraint.ts:164

---

isBodyToPoint

▸ isBodyToPoint(): boolean

Determines wether or not the constraint is between a body and a point.

Returns

boolean

Wether or not the constraint is between a body and a point.

Inherited from

Constraint.isBodyToPoint

Defined in

src/physics/constraints/constraint.ts:107

---

kScalar

▸ Protected kScalar(n): number

Computes the k scalar value for the constraint.

Parameters

Name	Type	Description
n	vec2	The constraint's delta normal

Returns

number

The k scalar value for the constraint

Inherited from

Constraint.kScalar

Defined in

src/physics/constraints/constraint.ts:205

---

kScalarBody

▸ Protected kScalarBody(body, r, n): number

Computes the k scalar value for the given body.

Parameters

Name	Type	Description
body	CollisionObject	The body to calculate for
r	vec2	The anchor point on the body
n	vec2	The constraint's delta normal

Returns

number

The k scalar value for the given body

Inherited from

Constraint.kScalarBody

Defined in

src/physics/constraints/constraint.ts:194

---

kTensor

▸ Protected kTensor(): mat2

Computes the k tensor matrix for the constraint.

see Chipmunk2D kTensor

Returns

mat2

k tensor matrix

Inherited from

Constraint.kTensor

Defined in

src/physics/constraints/constraint.ts:220

---

postSolve

▸ postSolve(): void

Applies the cached impulse.

Returns

void

Overrides

Constraint.postSolve

Defined in

src/physics/constraints/pivot.ts:119

---

preSolve

▸ preSolve(dt): void

Prepares for constraint solving.

Parameters

Name	Type
dt	number

Returns

void

Overrides

Constraint.preSolve

Defined in

src/physics/constraints/pivot.ts:65

---

solve

▸ solve(dt): void

Computes and applies the impulse to keep the bodies at the joint's length.

see Chipmunk2D Pin Joint

see MatterJS Constraint

see Dyn4j Distance Constraint

see Constraints and Solvers

Parameters

Name	Type	Description
dt	number	The time since the last update

Returns

void

Overrides

Constraint.solve

Defined in

src/physics/constraints/pivot.ts:95

---

updateAnchors

▸ Protected updateAnchors(): void

Updates the constraint's anchor points to match the rotations of their bodies.

Returns

void

Inherited from

Constraint.updateAnchors

Defined in

src/physics/constraints/constraint.ts:141