Box2D b2Chain documentation

Functions for Box2D v3 chains. A chain owns multiple connected segment shapes, so it is represented by a separate b2Chain handle.

Version: alpha

TYPES
b2Chain	Box2D chain

FUNCTIONS
b2d.chain.destroy()	Destroy a chain.
b2d.chain.from_shape()	Get the parent chain for a chain segment shape.
b2d.chain.get_friction()	Get chain friction.
b2d.chain.get_geometry()	Get the chain geometry.
b2d.chain.get_material()	Get chain material id.
b2d.chain.get_restitution()	Get chain restitution.
b2d.chain.get_segment_count()	Get the number of segment shapes in a chain.
b2d.chain.get_segments()	Get the segment shapes owned by a chain.
b2d.chain.get_world()	Get the world owning a chain.
b2d.chain.is_valid()	Validate a chain handle.
b2d.chain.set_friction()	Set chain friction.
b2d.chain.set_material()	Set chain material id.
b2d.chain.set_restitution()	Set chain restitution.

Types

b2Chain

b2Chain = userdata

An opaque handle to a chain of connected segment shapes attached to a b2Body. Create one with b2d.body.create_chain, use the functions in b2d.chain to inspect or configure it, and release it with b2d.chain.destroy. Destroying its body also destroys the chain.

EXAMPLES

local body = b2d.get_body("#collisionobject")
local chain = b2d.body.create_chain(body, {
    vertices = {
        vmath.vector3(-64, 0, 0),
        vmath.vector3(0, 16, 0),
        vmath.vector3(64, 0, 0),
    },
})
print(b2d.chain.get_segment_count(chain))

Functions

b2d.chain.destroy()

b2d.chain.destroy(chain:b2Chain)

Destroying a chain removes all segment shapes owned by the chain. Destroying any segment shape through b2d.body.destroy_shape also destroys its parent chain.

PARAMETERS

chain b2Chain chain

b2d.chain.from_shape()

b2d.chain.from_shape(shape_id:b2Shape)→chain:b2Chain|nil

Returns nil if the shape is not a chain segment.

PARAMETERS

shape_id b2Shape shape handle from a shape info table, or pass body, shape_index

RETURNS

chain b2Chain
nil parent chain, or nil if the shape is not a chain segment

b2d.chain.get_friction()

b2d.chain.get_friction(chain:b2Chain)→friction:number

Get chain friction.

PARAMETERS

chain b2Chain chain

RETURNS

friction number chain friction

b2d.chain.get_geometry()

b2d.chain.get_geometry(chain:b2Chain)→geometry:b2d.chain_geometry

Get the chain geometry.

PARAMETERS

chain b2Chain chain

RETURNS

geometry b2d.chain_geometry chain geometry

b2d.chain.get_material()

b2d.chain.get_material(chain:b2Chain)→material:integer

Get chain material id.

PARAMETERS

chain b2Chain chain

RETURNS

material integer chain material id

b2d.chain.get_restitution()

b2d.chain.get_restitution(chain:b2Chain)→restitution:number

Get chain restitution.

PARAMETERS

chain b2Chain chain

RETURNS

restitution number chain restitution

b2d.chain.get_segment_count()

b2d.chain.get_segment_count(chain:b2Chain)→count:integer

Get the number of segment shapes in a chain.

PARAMETERS

chain b2Chain chain

RETURNS

count integer segment count

b2d.chain.get_segments()

b2d.chain.get_segments(chain:b2Chain)→segments:b2d.shape_info[]

Get the segment shapes owned by a chain.

PARAMETERS

chain b2Chain chain

RETURNS

segments b2d.shape_info[] chain segment shapes

b2d.chain.get_world()

b2d.chain.get_world(chain:b2Chain)→world:b2World

Get the world owning a chain.

PARAMETERS

chain b2Chain chain

RETURNS

world b2World owning world

b2d.chain.is_valid()

b2d.chain.is_valid(chain:b2Chain)→valid:boolean

Validate a chain handle.

PARAMETERS

chain b2Chain chain

RETURNS

valid boolean true if the chain handle still refers to a live Box2D chain

b2d.chain.set_friction()

b2d.chain.set_friction(chain:b2Chain, friction:number)

Set chain friction.

PARAMETERS

`chain`	`b2Chain`	chain
`friction`	`number`	chain friction

b2d.chain.set_material()

b2d.chain.set_material(chain:b2Chain, material:integer)

Set chain material id.

PARAMETERS

`chain`	`b2Chain`	chain
`material`	`integer`	chain material id

b2d.chain.set_restitution()

b2d.chain.set_restitution(chain:b2Chain, restitution:number)

Set chain restitution.

PARAMETERS

`chain`	`b2Chain`	chain
`restitution`	`number`	chain restitution