Physics

Rigid bodies attached to nodes.

import { PhysicsConfig, PhysicsBody, PhysicsBodyDef, PhysicsDynamic, PhysicsStatic, PhysicsKinematic, PhysicsShape, PhysicsCircle, PhysicsBox, PhysicsSegment, PhysicsPolygon, PhysicsBodyKind, PhysicsShapeKind } from "willow";

PhysicsConfig

class PhysicsConfig

Tunables for a physics world, passed to Node.enablePhysics.

PhysicsConfig: constructors

new PhysicsConfig(gravity?: Vec2, iterations?: int, sleepTime?: float)

PhysicsConfig: properties

Member	Description
gravity: Vec2	Gravity in pixels per second squared; positive y points down the screen.
iterations: int	Solver iterations per step; 0 keeps the engine default (10).
sleepTime: float	Seconds a resting body waits before it sleeps; 0 never sleeps.

PhysicsBody

class PhysicsBody

The live body attached to a node, from Node.getBody(). Reading it after the node was disposed or its body removed raises InvalidStateError.

PhysicsBody: properties

Member	Description
readonly kind: int	Which body this is: one of the PhysicsBodyKind constants.

PhysicsBody: methods

Member	Description
enabled(): boolean	True while the body takes part in the simulation (see Node.setBodyEnabled).
position(): Vec2	The body's position in its physics root's space.
angle(): float	The body's rotation in radians.
velocity(): Vec2	The body's linear velocity in pixels per second.
angularVelocity(): float	The body's angular velocity in radians per second.
mass(): float	The body's mass.
moment(): float	The body's moment of inertia.
friction(): float	The shape's friction coefficient.
elasticity(): float	The shape's elasticity.
setPosition(position: Vec2): void	Moves the body (and, on the next step, its node) to position.
setAngle(radians: float): void	Rotates the body to radians.
setVelocity(velocity: Vec2): void	Sets the linear velocity in pixels per second.
setAngularVelocity(velocity: float): void	Sets the angular velocity in radians per second.
applyImpulse(impulse: Vec2): void	Applies an instant impulse at the centre of gravity.
applyForce(force: Vec2): void	Applies a force at the centre of gravity until the next step.

PhysicsBodyDef

class PhysicsBodyDef

A body description passed to Node.setBody. Build one with PhysicsDynamic, PhysicsStatic or PhysicsKinematic.

PhysicsBodyDef: properties

Member	Description
readonly kind: int	Which body this is: one of the PhysicsBodyKind constants.
shape: PhysicsShape	The collider of the body.
mass: float	Mass; must be above 0 for a dynamic body.
friction: float	Surface friction coefficient.
elasticity: float	Bounciness, 0 (none) to 1 (perfectly elastic).
moment: float	Moment of inertia; 0 computes it from the shape and mass.

PhysicsDynamic

class PhysicsDynamic extends PhysicsBodyDef

Extends PhysicsBodyDef.

A body driven by forces, impulses and collisions.

PhysicsDynamic: constructors

new PhysicsDynamic(shape: PhysicsShape, mass: float, friction?: float, elasticity?: float, moment?: float)

PhysicsStatic

class PhysicsStatic extends PhysicsBodyDef

Extends PhysicsBodyDef.

An immovable body used for terrain and obstacles.

PhysicsStatic: constructors

new PhysicsStatic(shape: PhysicsShape, friction?: float, elasticity?: float)

PhysicsKinematic

class PhysicsKinematic extends PhysicsBodyDef

Extends PhysicsBodyDef.

A body moved by script that ignores forces and gravity.

PhysicsKinematic: constructors

new PhysicsKinematic(shape: PhysicsShape, friction?: float)

PhysicsShape

class PhysicsShape

A collider descriptor. Build one with PhysicsCircle, PhysicsBox, PhysicsSegment or PhysicsPolygon.

PhysicsShape: properties

Member	Description
readonly kind: int	Which collider this is: one of the PhysicsShapeKind constants.

PhysicsCircle

class PhysicsCircle extends PhysicsShape

Extends PhysicsShape.

A circular collider.

PhysicsCircle: constructors

new PhysicsCircle(radius: float, offset?: Vec2)

PhysicsCircle: properties

Member	Description
radius: float	Circle radius in pixels.
offset: Vec2	Centre of the circle relative to the node's position.

PhysicsBox

class PhysicsBox extends PhysicsShape

Extends PhysicsShape.

A rectangular collider centred on the node's position.

PhysicsBox: constructors

new PhysicsBox(width: float, height: float, cornerRadius?: float)

PhysicsBox: properties

Member	Description
width: float	Box width in pixels.
height: float	Box height in pixels.
cornerRadius: float	Radius that rounds the corners; 0 keeps them square.

PhysicsSegment

class PhysicsSegment extends PhysicsShape

Extends PhysicsShape.

A line-segment collider.

PhysicsSegment: constructors

new PhysicsSegment(a: Vec2, b: Vec2, radius?: float)

PhysicsSegment: properties

Member	Description
a: Vec2	First endpoint relative to the node's position.
b: Vec2	Second endpoint relative to the node's position.
radius: float	Thickness radius around the segment; 0 is a hairline.

PhysicsPolygon

class PhysicsPolygon extends PhysicsShape

Extends PhysicsShape.

A convex polygon collider.

PhysicsPolygon: constructors

new PhysicsPolygon(verts: Array<Vec2>, cornerRadius?: float)

PhysicsPolygon: properties

Member	Description
verts: Array<Vec2>	Polygon points relative to the node's position; the convex hull is used.
cornerRadius: float	Radius that rounds the corners; 0 keeps them sharp.

PhysicsBodyKind

class PhysicsBodyKind

Which kind of body a physics definition describes.

PhysicsBodyKind: static properties

Member	Description
static readonly DYNAMIC: int	Driven by forces, impulses and collisions.
static readonly STATIC: int	Immovable terrain and obstacles.
static readonly KINEMATIC: int	Moved by script (a velocity or a position), ignoring forces and gravity.

PhysicsShapeKind

class PhysicsShapeKind

Which collider a physics shape describes.

PhysicsShapeKind: static properties

Member	Description
static readonly CIRCLE: int	A circle, optionally offset from the node's position.
static readonly BOX: int	A box centred on the node's position.
static readonly SEGMENT: int	A line segment with an optional thickness.
static readonly POLYGON: int	A convex polygon; the convex hull of the points is used.