Box2dObject

Create a LittleJS object with Box2d physics

The Box2d body, undefined once it is destroyed

List of all edges for default box2d drawing

List of all edge loops for default box2d drawing

Line color used for default box2d drawing

Line width used for default box2d drawing

How fast its surface moves, clockwise around it, in world units per second, like a conveyor belt: what touches it is carried along by friction, to the right across its top when positive; set it with setSurfaceSpeed, which wakes what rests on it

Add a box shape to the body

Add a circle shape to the body

Add an edge shape to the body

Add an edge list to the body

Add an edge loop to the body, an edge loop connects the end points

Add a polygon shape to the body, the convex hull of its points; Box2D takes 3 to 8 points, not all in a line, and no fixture is made from any other; points closer than .001 count as one

Add a random polygon shape to the body

Add a regular polygon shape to the body

Add a shape fixture to the body

Apply acceleration to this object (changes velocity by acceleration, mass-independent like EngineObject.applyAcceleration, but in units per second). Use applyImpulse if you want the mass-dependent velocity change Δv = impulse / mass, or applyForce for a Newton-style sustained force.

Apply angular acceleration to this object (changes angular velocity by acceleration, mass-independent, clockwise — matches EngineObject.applyAngularAcceleration).

Apply an instantaneous angular impulse. Changes angular velocity by impulse / inertia immediately, clockwise like angle.

Apply force to this object

Apply an instantaneous linear impulse. Changes velocity immediately by impulse / mass (so heavier bodies move less for the same impulse).

Apply torque to this object, clockwise like angle

Called when a contact begins, while the world steps: a destroy or a setter waits until the step is done, and creating objects, fixtures or joints must wait until after the step

• The fixtures say which shapes touched, the same objects addBox and the others returned, so a small sensor under a player's feet can tell standing on the ground from touching a wall
• impactSpeed is how fast they were closing along the contact normal, spin included, in world units per second, measured before the solver pushed them apart; 0 for a sensor
• contact has where they touched, the normal toward this object and the impulse of the hit, which counts their mass and how it is spread: a stick heavy at its ends hits harder than one heavy in the middle, spinning at the same speed

Destroy this object and its physics body

Destroy all fixtures from the body, from a contact callback once the step is done

Destroy a fixture from the body, from a contact callback once the step is done

Draw all this object's fixtures

Called when a contact ends, while the world steps or a body is destroyed: a destroy or a setter waits until the step is done, and creating objects, fixtures or joints must wait until after the step

Gets the angular velocity, clockwise like angle

Gets the physics body type

Gets the center of mass in world space

Get list of fixtures for this object

Gets the rotational inertia about the center of mass

Check if this object is awake

Get list of joints for this object, the Box2dJoint for each one made through LittleJS, and the Box2D joint, cast to its type, for any made on the world directly

Gets the linear velocity

Gets the mass

Get the speed of this object

Get the velocity of a point on this object, its linear velocity and its spin about its center of mass together, in Box2D's units like getLinearVelocity

Check if this object has any fixtures

Check if this object has any joints

Called before Box2D solves a contact, each step while they touch, for an object that overrides it, while the world steps as beginContact is; change the contact to change how they collide

• enabled false lets them pass through each other until they stop touching, like a platform dropped through
• friction and restitution are kept while they touch, surfaceSpeed is for this step, like a patch of a belt
• A sleeping body's contacts are not solved, so wake it with setAwake for this to be called, as for a player standing still on a platform it drops through

Render the object, uses box2d drawing if no tile info exists

Draw its fixtures for the debug view: yellow asleep, blue static, both when both

Reset the mass, center of mass, and moment, from a contact callback once the step is done

Sets the angle, from a contact callback the body turns once the step is done, keeping the position it has then

Sets the angular damping, Box2D's: a rate, 0 none and larger slows its turning faster, with no upper limit; angleDamping does nothing on a Box2dObject

Sets the angular velocity, clockwise like angle

Set the sleep state of the body

Set the physics body type, from a contact callback it changes once the step is done

Should be like a bullet for continuous collision detection?

Set the center of mass of the body, local to it

Set the collision filter data for the fixtures this body has now, a fixture added later has the default filter, category 1 colliding with everything

Set whether the body can rotate

Sets the gravity scale

Sets the linear damping, Box2D's: a rate, 0 none and larger slows it faster, with no upper limit, where the damping of an EngineObject is the fraction it keeps each frame and does nothing on a Box2dObject

Sets the linear velocity

Set the mass of the body

Set the mass data of the body, from a contact callback once the step is done; a mass of 0 or less becomes 1, use setBodyType for a static body; call it after adding fixtures and after setFixedRotation, both of which put the mass back to what the fixtures give

Set the moment of inertia of the body, about its center of mass

Sets the position, from a contact callback the body moves once the step is done, keeping the angle it has then

Set if this body is a sensor

Set whether the body is allowed to sleep

Sets how fast its surface moves, clockwise around it, like a conveyor belt, see surfaceSpeed

Sets the position and angle, from a contact callback the body moves once the step is done

Box2d objects updated with Box2d world step

Update the object transform, called automatically by engine even when paused; its body places it, so it can be a parent but not a child, connect it to another with a joint