Class Constraint

debugDraw

active

• get active(): boolean

  Whether the constraint is currently active (enforced by the solver).

  Deactivating a constraint suspends it without removing it from the space.

  Returns boolean

  Default Value

  true

• set active(value: boolean): void

  Parameters

  • value: boolean

  Returns void

breakUnderError

• get breakUnderError(): boolean

  When true, the constraint breaks if the positional error exceeds maxError.

  Returns boolean

  Default Value

  false

• set breakUnderError(value: boolean): void

  Parameters

  • value: boolean

  Returns void

breakUnderForce

• get breakUnderForce(): boolean

  When true, the constraint breaks (fires a BREAK event) if the applied force exceeds maxForce in a single step.

  Returns boolean

  Default Value

  false

• set breakUnderForce(value: boolean): void

  Parameters

  • value: boolean

  Returns void

cbTypes

• get cbTypes(): object

  The set of CbTypes assigned to this constraint. Used to filter which listeners respond to this constraint's events.

  Returns object

compound

• get compound(): Compound | null

  The compound this constraint belongs to, or null. When set, the constraint's space is managed by the compound.

  Returns Compound | null

• set compound(value: Compound | null): void

  Parameters

  • value: Compound | null

  Returns void

damping

• get damping(): number

  Damping ratio for soft constraints (stiff = false).

  0 = undamped (oscillates freely), 1 = critically damped. Values > 1 are overdamped. Must be >= 0. Ignored when stiff is true.

  Returns number

  Default Value

  1

• set damping(value: number): void

  Parameters

  • value: number

  Returns void

frequency

• get frequency(): number

  Spring frequency in Hz for soft constraints (stiff = false).

  Higher values make the spring stiffer; lower values make it bouncier. Must be > 0. Ignored when stiff is true.

  Returns number

  Default Value

  10

• set frequency(value: number): void

  Parameters

  • value: number

  Returns void

ignore

• get ignore(): boolean

  When true the constraint is completely ignored by the engine — bodies are not woken, no impulse is applied, and no callbacks fire.

  Returns boolean

  Default Value

  false

• set ignore(value: boolean): void

  Parameters

  • value: boolean

  Returns void

isSleeping

• get isSleeping(): boolean

  Whether the constraint's simulation component is currently sleeping.

  Only valid when the constraint is active and in a space — throws otherwise.

  Returns boolean

maxError

• get maxError(): number

  Maximum positional error (in pixels) allowed before breaking.

  Only meaningful when breakUnderError is true. Must be >= 0. Infinity disables the limit.

  Returns number

  Default Value

  Infinity

• set maxError(value: number): void

  Parameters

  • value: number

  Returns void

maxForce

• get maxForce(): number

  Maximum force (in Newtons) the constraint may apply per step.

  When the required force exceeds this value the constraint becomes slack. If breakUnderForce is true the constraint breaks instead. Must be >= 0. Infinity disables the limit.

  Returns number

  Default Value

  Infinity

• set maxForce(value: number): void

  Parameters

  • value: number

  Returns void

removeOnBreak

• get removeOnBreak(): boolean

  When true (default), the constraint is automatically removed from its space when it breaks. Set to false to keep it in the space after breaking.

  Returns boolean

  Default Value

  true

• set removeOnBreak(value: boolean): void

  Parameters

  • value: boolean

  Returns void

space

• get space(): Space | null

  The space this constraint belongs to, or null if not in a space.

  Assign to add/remove the constraint from a space:

  joint.space = mySpace;  // adds to space
  joint.space = null;     // removes from space
  Copy

  Cannot be set if the constraint belongs to a Compound.

  Returns Space | null

• set space(value: Space | null): void

  Parameters

  • value: Space | null

  Returns void

stiff

• get stiff(): boolean

  When true (default) the constraint is stiff/rigid. When false the constraint uses a soft spring model driven by frequency and damping.

  Returns boolean

  Default Value

  true

• set stiff(value: boolean): void

  Parameters

  • value: boolean

  Returns void

userData

• get userData(): Record<string, unknown>

  Arbitrary user data attached to this constraint. Lazily initialized to {} on first access.

  Returns Record<string, unknown>

bodyImpulse

• bodyImpulse(_body: Body): Vec3 | null

  The impulse applied to body by this constraint in the last simulation step, expressed as a Vec3 (fx, fy, torque).

  Parameters

  • _body: Body

    Must be one of the bodies linked to this constraint.

  Returns Vec3 | null

copy

• copy(): Constraint

  Creates and returns a copy of this constraint with the same parameters. The copy is not automatically added to a space.

  Returns Constraint

impulse

• impulse(): MatMN | null

  The impulse applied by this constraint in the last simulation step.

  The shape of the returned MatMN depends on the constraint's degrees of freedom (e.g., 1×1 for AngleJoint/MotorJoint, 2×1 for PivotJoint/LineJoint, 3×1 for WeldJoint).

  Returns MatMN | null

toString

• toString(): string

  Returns string

visitBodies

• visitBodies(_fn: (body: Body) => void): void

  Invokes fn once for each distinct body linked to this constraint.

  Parameters

  • _fn: (body: Body) => void

    Function to call for each body.

  Returns void