Mirror Engine API / RigidBodyComponent
Class: RigidBodyComponent
The rigidbody component, when combined with a CollisionComponent, allows your entities to be simulated using realistic physics. A rigidbody component will fall under gravity and collide with other rigid bodies. Using scripts, you can apply forces and impulses to rigid bodies.
You should never need to use the RigidBodyComponent constructor. To add an RigidBodyComponent to a Entity, use Entity#addComponent:
// Create a static 1x1x1 box-shaped rigid body
const entity = Entity()
entity.addComponent('rigidbody') // Without options, this defaults to a 'static' body
entity.addComponent('collision') // Without options, this defaults to a 1x1x1 box shape
To create a dynamic sphere with mass of 10, do:
const entity = Entity()
entity.addComponent('rigidbody', {
type: BODYTYPE_DYNAMIC,
mass: 10
})
entity.addComponent('collision', {
type: 'sphere'
})
Extends
Component
Properties
entity
entity: Entity
The Entity that this Component is attached to.
Inherited from
Component.entity
system
system: ComponentSystem
The ComponentSystem used to create this Component.
Inherited from
Component.system
angularDamping
Get Signature
get angularDamping(): number
Gets the rate at which a body loses angular velocity over time.
Returns
number
Set Signature
set angularDamping(damping: number): void
Sets the rate at which a body loses angular velocity over time.
Parameters
damping
number
Returns
void
angularFactor
Get Signature
get angularFactor(): Vec3
Gets the scaling factor for angular movement of the body in each axis.
Returns
Set Signature
set angularFactor(factor: Vec3): void
Sets the scaling factor for angular movement of the body in each axis. Only valid for rigid bodies of type BODYTYPE_DYNAMIC. Defaults to 1 in all axes (body can freely rotate).
Parameters
factor
Returns
void
angularVelocity
Get Signature
get angularVelocity(): Vec3
Gets the rotational speed of the body around each world axis.
Returns
Set Signature
set angularVelocity(velocity: Vec3): void
Sets the rotational speed of the body around each world axis.
Parameters
velocity
Returns
void
enabled
Get Signature
get enabled(): boolean
Gets the enabled state of the component.
Returns
boolean
Set Signature
set enabled(arg: boolean): void
Sets the enabled state of the component.
Parameters
arg
boolean
Returns
void
Inherited from
Component.enabled
friction
Get Signature
get friction(): number
Gets the friction value used when contacts occur between two bodies.
Returns
number
Set Signature
set friction(friction: number): void
Sets the friction value used when contacts occur between two bodies. A higher value indicates more friction. Should be set in the range 0 to 1. Defaults to 0.5.
Parameters
friction
number
Returns
void
group
Get Signature
get group(): number
Gets the collision group this body belongs to.
Returns
number
Set Signature
set group(group: number): void
Sets the collision group this body belongs to. Combine the group and the mask to prevent bodies colliding with each other. Defaults to 1.
Parameters
group
number
Returns
void
linearDamping
Get Signature
get linearDamping(): number
Gets the rate at which a body loses linear velocity over time.
Returns
number
Set Signature
set linearDamping(damping: number): void
Sets the rate at which a body loses linear velocity over time. Defaults to 0.
Parameters
damping
number
Returns
void
linearFactor
Get Signature
get linearFactor(): Vec3
Gets the scaling factor for linear movement of the body in each axis.
Returns
Set Signature
set linearFactor(factor: Vec3): void
Sets the scaling factor for linear movement of the body in each axis. Only valid for rigid bodies of type BODYTYPE_DYNAMIC. Defaults to 1 in all axes (body can freely move).
Parameters
factor
Returns
void
linearVelocity
Get Signature
get linearVelocity(): Vec3
Gets the speed of the body in a given direction.
Returns
Set Signature
set linearVelocity(velocity: Vec3): void
Sets the speed of the body in a given direction.
Parameters
velocity
Returns
void
mask
Get Signature
get mask(): number
Gets the collision mask sets which groups this body collides with.
Returns
number
Set Signature
set mask(mask: number): void
Sets the collision mask sets which groups this body collides with. It is a bit field of 16 bits, the first 8 bits are reserved for engine use. Defaults to 65535.
Parameters
mask
number
Returns
void
mass
Get Signature
get mass(): number
Gets the mass of the body.
Returns
number
Set Signature
set mass(mass: number): void
Sets the mass of the body. This is only relevant for BODYTYPE_DYNAMIC bodies, other types have infinite mass. Defaults to 1.
Parameters
mass
number
Returns
void
restitution
Get Signature
get restitution(): number
Gets the value that controls the amount of energy lost when two rigid bodies collide.
Returns
number
Set Signature
set restitution(restitution: number): void
Sets the value that controls the amount of energy lost when two rigid bodies collide. The calculation multiplies the restitution values for both colliding bodies. A multiplied value of 0 means that all energy is lost in the collision while a value of 1 means that no energy is lost. Should be set in the range 0 to 1. Defaults to 0.
Parameters
restitution
number
Returns
void
rollingFriction
Get Signature
get rollingFriction(): number
Gets the torsional friction orthogonal to the contact point.
Returns
number
Set Signature
set rollingFriction(friction: number): void
Sets the torsional friction orthogonal to the contact point. Defaults to 0.
Parameters
friction
number
Returns
void
type
Get Signature
get type(): string
Gets the rigid body type determines how the body is simulated.
Returns
string
Set Signature
set type(type: string): void
Sets the rigid body type determines how the body is simulated. Can be:
- BODYTYPE_STATIC: infinite mass and cannot move.
- BODYTYPE_DYNAMIC: simulated according to applied forces.
- BODYTYPE_KINEMATIC: infinite mass and does not respond to forces (can only be moved by setting the position and rotation of component's Entity).
Defaults to BODYTYPE_STATIC.
Parameters
type
string
Returns
void
Methods
activate()
activate(): void
Forcibly activate the rigid body simulation. Only affects rigid bodies of type BODYTYPE_DYNAMIC.
Returns
void
applyForce()
applyForce(
x: number | Vec3,
y?: number | Vec3,
z?: number,
px?: number,
py?: number,
pz?: number): void
Apply an force to the body at a point. By default, the force is applied at the origin of the body. However, the force can be applied at an offset this point by specifying a world space vector from the body's origin to the point of application. This function has two valid signatures. You can either specify the force (and optional relative point) via 3D-vector or numbers.
Parameters
x
A 3-dimensional vector representing the force in world space or the x-component of the force in world space.
number | Vec3
y?
An optional 3-dimensional vector representing the relative point at which to apply the impulse in world space or the y-component of the force in world space.
number | Vec3
z?
number
The z-component of the force in world space.
px?
number
The x-component of a world space offset from the body's position where the force is applied.
py?
number
The y-component of a world space offset from the body's position where the force is applied.
pz?
number
The z-component of a world space offset from the body's position where the force is applied.
Returns
void
Examples
// Apply an approximation of gravity at the body's center
this.entity.rigidbody.applyForce(0, -10, 0)
// Apply an approximation of gravity at 1 unit down the world Z from the center of the body
this.entity.rigidbody.applyForce(0, -10, 0, 0, 0, 1)
// Apply a force at the body's center
// Calculate a force vector pointing in the world space direction of the entity
const force = this.entity.forward.clone().mulScalar(100)
// Apply the force
this.entity.rigidbody.applyForce(force)
// Apply a force at some relative offset from the body's center
// Calculate a force vector pointing in the world space direction of the entity
const force = this.entity.forward.clone().mulScalar(100)
// Calculate the world space relative offset
const relativePos = new Vec3()
const childEntity = this.entity.findByName('Engine')
relativePos.sub2(childEntity.getPosition(), this.entity.getPosition())
// Apply the force
this.entity.rigidbody.applyForce(force, relativePos)
applyImpulse()
applyImpulse(
x: number | Vec3,
y?: number | Vec3,
z?: number,
px?: number,
py?: number,
pz?: number): void
Apply an impulse (instantaneous change of velocity) to the body at a point. This function has two valid signatures. You can either specify the impulse (and optional relative point) via 3D-vector or numbers.
Parameters
x
A 3-dimensional vector representing the impulse in world space or the x-component of the impulse in world space.
number | Vec3
y?
An optional 3-dimensional vector representing the relative point at which to apply the impulse in the local space of the entity or the y-component of the impulse to apply in world space.
number | Vec3
z?
number
The z-component of the impulse to apply in world space.
px?
number
The x-component of the point at which to apply the impulse in the local space of the entity.
py?
number
The y-component of the point at which to apply the impulse in the local space of the entity.
pz?
number
The z-component of the point at which to apply the impulse in the local space of the entity.
Returns
void
Examples
// Apply an impulse along the world space positive y-axis at the entity's position.
const impulse = new Vec3(0, 10, 0)
entity.rigidbody.applyImpulse(impulse)
// Apply an impulse along the world space positive y-axis at 1 unit down the positive
// z-axis of the entity's local space.
const impulse = new Vec3(0, 10, 0)
const relativePoint = new Vec3(0, 0, 1)
entity.rigidbody.applyImpulse(impulse, relativePoint)
// Apply an impulse along the world space positive y-axis at the entity's position.
entity.rigidbody.applyImpulse(0, 10, 0)
// Apply an impulse along the world space positive y-axis at 1 unit down the positive
// z-axis of the entity's local space.
entity.rigidbody.applyImpulse(0, 10, 0, 0, 0, 1)
applyTorque()
applyTorque(
x: number | Vec3,
y?: number,
z?: number): void
Apply torque (rotational force) to the body. This function has two valid signatures. You can either specify the torque force with a 3D-vector or with 3 numbers.
Parameters
x
A 3-dimensional vector representing the torque force in world space or the x-component of the torque force in world space.
number | Vec3
y?
number
The y-component of the torque force in world space.
z?
number
The z-component of the torque force in world space.
Returns
void
Examples
// Apply via vector
const torque = new Vec3(0, 10, 0)
entity.rigidbody.applyTorque(torque)
// Apply via numbers
entity.rigidbody.applyTorque(0, 10, 0)
applyTorqueImpulse()
applyTorqueImpulse(
x: number | Vec3,
y?: number,
z?: number): void
Apply a torque impulse (rotational force applied instantaneously) to the body. This function has two valid signatures. You can either specify the torque force with a 3D-vector or with 3 numbers.
Parameters
x
A 3-dimensional vector representing the torque impulse in world space or the x-component of the torque impulse in world space.
number | Vec3
y?
number
The y-component of the torque impulse in world space.
z?
number
The z-component of the torque impulse in world space.
Returns
void
Examples
// Apply via vector
const torque = new Vec3(0, 10, 0)
entity.rigidbody.applyTorqueImpulse(torque)
// Apply via numbers
entity.rigidbody.applyTorqueImpulse(0, 10, 0)
fire()
fire(
name: string,
arg1?: any,
arg2?: any,
arg3?: any,
arg4?: any,
arg5?: any,
arg6?: any,
arg7?: any,
arg8?: any): EventHandler
Fire an event, all additional arguments are passed on to the event listener.
Parameters
name
string
Name of event to fire.
arg1?
any
First argument that is passed to the event handler.
arg2?
any
Second argument that is passed to the event handler.
arg3?
any
Third argument that is passed to the event handler.
arg4?
any
Fourth argument that is passed to the event handler.
arg5?
any
Fifth argument that is passed to the event handler.
arg6?
any
Sixth argument that is passed to the event handler.
arg7?
any
Seventh argument that is passed to the event handler.
arg8?
any
Eighth argument that is passed to the event handler.
Returns
Self for chaining.
Example
obj.fire('test', 'This is the message')
Inherited from
Component.fire
hasEvent()
hasEvent(name: string): boolean
Test if there are any handlers bound to an event name.
Parameters
name
string
The name of the event to test.
Returns
boolean
True if the object has handlers bound to the specified event name.
Example
obj.on('test', () => {}) // bind an event to 'test'
obj.hasEvent('test') // returns true
obj.hasEvent('hello') // returns false
Inherited from
Component.hasEvent
isActive()
isActive(): boolean
Returns true if the rigid body is currently actively being simulated. I.e. Not 'sleeping'.
Returns
boolean
True if the body is active.
isKinematic()
isKinematic(): boolean
Returns true if the rigid body is of type BODYTYPE_KINEMATIC.
Returns
boolean
True if kinematic.
isStatic()
isStatic(): boolean
Returns true if the rigid body is of type BODYTYPE_STATIC.
Returns
boolean
True if static.
isStaticOrKinematic()
isStaticOrKinematic(): boolean
Returns true if the rigid body is of type BODYTYPE_STATIC or BODYTYPE_KINEMATIC.
Returns
boolean
True if static or kinematic.
off()
off(
name?: string,
callback?: HandleEventCallback,
scope?: any): EventHandler
Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.
Parameters
name?
string
Name of the event to unbind.
callback?
HandleEventCallback
Function to be unbound.
scope?
any
Scope that was used as the this when the event is fired.
Returns
Self for chaining.
Example
const handler = () => {}
obj.on('test', handler)
obj.off() // Removes all events
obj.off('test') // Removes all events called 'test'
obj.off('test', handler) // Removes all handler functions, called 'test'
obj.off('test', handler, this) // Removes all handler functions, called 'test' with scope this
Inherited from
Component.off
on()
on(
name: string,
callback: HandleEventCallback,
scope?: any): EventHandle
Attach an event handler to an event.
Parameters
name
string
Name of the event to bind the callback to.
callback
HandleEventCallback
Function that is called when event is fired. Note the callback is limited to 8 arguments.
scope?
any = ...
Object to use as 'this' when the event is fired, defaults to current this.
Returns
Can be used for removing event in the future.
Examples
obj.on('test', (a, b) => {
console.log(a + b)
})
obj.fire('test', 1, 2) // prints 3 to the console
const evt = obj.on('test', (a, b) => {
console.log(a + b)
})
// some time later
evt.off()
Inherited from
Component.on
once()
once(
name: string,
callback: HandleEventCallback,
scope?: any): EventHandle
Attach an event handler to an event. This handler will be removed after being fired once.
Parameters
name
string
Name of the event to bind the callback to.
callback
HandleEventCallback
Function that is called when event is fired. Note the callback is limited to 8 arguments.
scope?
any = ...
Object to use as 'this' when the event is fired, defaults to current this.
Returns
- can be used for removing event in the future.
Example
obj.once('test', (a, b) => {
console.log(a + b)
})
obj.fire('test', 1, 2) // prints 3 to the console
obj.fire('test', 1, 2) // not going to get handled
Inherited from
Component.once
teleport()
teleport(
x: number | Vec3,
y?: number | Vec3 | Quat,
z?: number,
rx?: number,
ry?: number,
rz?: number): void
Teleport an entity to a new world space position, optionally setting orientation. This function should only be called for rigid bodies that are dynamic. This function has three valid signatures. The first takes a 3-dimensional vector for the position and an optional 3-dimensional vector for Euler rotation. The second takes a 3-dimensional vector for the position and an optional quaternion for rotation. The third takes 3 numbers for the position and an optional 3 numbers for Euler rotation.
Parameters
x
A 3-dimensional vector holding the new position or the new position x-coordinate.
number | Vec3
y?
A 3-dimensional vector or quaternion holding the new rotation or the new position y-coordinate.
z?
number
The new position z-coordinate.
rx?
number
The new Euler x-angle value.
ry?
number
The new Euler y-angle value.
rz?
number
The new Euler z-angle value.
Returns
void
Examples
// Teleport the entity to the origin
entity.rigidbody.teleport(Vec3.ZERO)
// Teleport the entity to the origin
entity.rigidbody.teleport(0, 0, 0)
// Teleport the entity to world space coordinate [1, 2, 3] and reset orientation
const position = new Vec3(1, 2, 3)
entity.rigidbody.teleport(position, Vec3.ZERO)
// Teleport the entity to world space coordinate [1, 2, 3] and reset orientation
entity.rigidbody.teleport(1, 2, 3, 0, 0, 0)
Events
EVENT_COLLISIONEND
static EVENT_COLLISIONEND: string = 'collisionend';
Fired when two rigid bodies stop touching. The handler is passed an Entity that represents the other rigid body involved in the collision.
Example
entity.rigidbody.on('collisionend', (other) => {
console.log(`${'${entity.name}'} stopped touching ${'${other.name}'}`)
})
EVENT_COLLISIONSTART
static EVENT_COLLISIONSTART: string = 'collisionstart';
Fired when two rigid bodies start touching. The handler is passed a ContactResult object containing details of the contact between the two rigid bodies.
Example
entity.rigidbody.on('collisionstart', (result) => {
console.log(
`Collision started between ${'${entity.name}'} and ${'${result.other.name}'}`
)
})
EVENT_CONTACT
static EVENT_CONTACT: string = 'contact';
Fired when a contact occurs between two rigid bodies. The handler is passed a ContactResult object containing details of the contact between the two rigid bodies.
Example
entity.rigidbody.on('contact', (result) => {
console.log(
`Contact between ${'${entity.name}'} and ${'${result.other.name}'}`
)
})
EVENT_TRIGGERENTER
static EVENT_TRIGGERENTER: string = 'triggerenter';
Fired when a rigid body enters a trigger volume. The handler is passed an Entity representing the trigger volume that this rigid body entered.
Example
entity.rigidbody.on('triggerenter', (trigger) => {
console.log(
`Entity ${'${entity.name}'} entered trigger volume ${'${trigger.name}'}`
)
})
EVENT_TRIGGERLEAVE
static EVENT_TRIGGERLEAVE: string = 'triggerleave';
Fired when a rigid body exits a trigger volume. The handler is passed an Entity representing the trigger volume that this rigid body exited.
Example
entity.rigidbody.on('triggerleave', (trigger) => {
console.log(
`Entity ${'${entity.name}'} exited trigger volume ${'${trigger.name}'}`
)
})