Category:Physics Engine/Bodies

A body holds the physical properties (mass, position, rotation, velocity, etc.) of an object. It does not have a shape until you attach one (or more) to it. Its type is TI.cpBody.

Body

body = physics.Body(mass, inertia)

Returns a new Body with the given mass and moment of inertia.

Use the provided helper functions to compute the moment of inertia.

Introduced in platform.apiLevel = '2.0'

activate

self = physics.Body:activate()

Activates a sleeping body.

Introduced in platform.apiLevel = '2.0'

angle

angle = physics.Body:angle()

Returns the angle in radians of the orientation of the body.

Introduced in platform.apiLevel = '2.0'

angVel

avel = physics.Body:angVel()

Returns the angular velocity of the body in radians per unit time.

Introduced in platform.apiLevel = '2.0'

applyForce

self = physics.Body:applyForce(forceVect, rOffset)

Apply force vector on self at a relative offset from the center of gravity.

Introducted in platform.apiLevel = '2.0'

applyImpulse

self = physics.Body:applyImpulse(impulseVect, rOffset)

Apply the impulse vector to self at a relative offset from the center of gravity.

Introducted in platform.apiLevel = '2.0'

data

obj = physics.Body:data()

Returns the contents of the programmer data field of the Body.

Introducted in platform.apiLevel = '2.0'

force

fvec = physics.Body:force()

Returns the force vector on the body.

Introduced in platform.apiLevel = '2.0'

isRogue

bool = physics.Body:isRogue()

Returns true if the Body is a rogue Body, never having been added to the simulation Space.

Introduced in platform.apiLevel = '2.0'

isSleeping

bool = physics.Body:isSleeping()

Returns true if the body is sleeping.

Introduced in platform.apiLevel = '2.0'

local2World

wvec = physics.Body:local2World(lvec)

Converts lvec from body-relative coordinates to world coordinates. Returns the converted vector.

Introduced in platform.apiLevel = '2.0'

kineticEnergy

ke = physics.Body:kineticEnergy()

Returns the kinetic energy of the body.

Introduced in platform.apiLevel = '2.0'

mass

m = physics.Body:mass()

Returns the mass of the body.

Introduced in platform.apiLevel = '2.0'

moment

m = physics.Body:moment()

Returns the moment of inertia of the body.

Introduced in platform.apiLevel = '2.0'

pos

p = physics.Body:pos()

Returns the vector position of the body.

Introduced in platform.apiLevel = '2.0'

resetForces

self = physics.Body:resetForces()

Zero both the force and torque accumulated on self.

Introducted in platform.apiLevel = '2.0'

rot

rvec = physics.Body:rot()

Returns the vector orientation of the body. This is a unit vector cached from the last calculated angle of the Body.

Introduced in platform.apiLevel = '2.0'

setAngle

self = physics.Body:setAngle(angle)

Updates the angle of rotation in radians of the body.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setAngVel

self = physics.Body:setAngVel(vel)

Updates the angular velocity of the body. The angular velocity is in radians per unit time.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setData

self = physics.Body:setData(value)

Sets the programmer data field of the Body. The programmer can store any Lua object in this field. This is a handy place to store a reference to a simulation object.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setForce

self = physics.Body:setForce(vector)

Updates the force vector on the body.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setMass

self = physics.Body:setMass(mass)

Updates the mass of the body.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setMoment

self = physics.Body:setMoment(moment)

Updates the moment of inertia of the body.

Use the provided helper functions to compute the moment of inertia.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setPos

self = physics.Body:setPos(vector)

Updates the position of the body.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setPositionFunc

self = physics.Body:setPositionFunc(func)

Sets the position function of the body. The position function must be a function that accepts a Body and a time step value and at some point calls body:updatePosition to update the position of the body.

Returns the Body.

-- TODO This is a lame example

function samplePositionFunc(body, dt)
-- What goes here?
body:updatePosition(dt)
end

body:setPositionFunc(samplePositionFunc)

Introduced in platform.apiLevel = '2.0'

setTorque

self = physics.Body:setTorque(torque)

Updates the torque on the body. Torque is a numeric magnitude.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setVel

self = physics.Body:setVel(vector)

Updates the velocity of the body.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setVelocityFunc

self = physics.Body:setVelocityFunc(func)

Sets the velocity function of the body. The velocity function must be a function that accepts a Body, a gravity vector, a numeric damping factor, and a time step value. The function should call body:updateVelocity to adjust the velocity of the body.

Returns the Body.

function sampleVelocityFunc(body, gravity, damping, dt)
local pos = body:pos()
local sqdist = pos:lengthsq()
local g = pos:mult(-GravityStrength / (sqdist * math.sqrt(sqdist)))
body:updateVelocity(g, damping, dt)
end

body:setVelocityFunc(sampleVelocityFunc)

Introduced in platform.apiLevel = '2.0'

setVLimit

self = physics.Body:setVLimit(limit)

Sets the limit for the maximum speed of the body.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

setWLimit

self = physics.Body:setWLimit(limit)

Updates the limit of the angular velocity of the body. Angular velocity is in radians per unit time.

Returns the Body.

Introduced in platform.apiLevel = '2.0'

sleep

self = physics.Body:sleep()

Puts the body to sleep.

Introduced in platform.apiLevel = '2.0'

sleepWithGroup

self = physics.Body:sleepWithGroup( [group] )

Puts the Body to sleep and adds it to a group of other sleeping bodies.

This routine will raise an exception if group is not sleeping.

Introduced in platform.apiLevel = '2.0'

torque

t = physics.Body:torque()

Returns the torque on the body.

Introduced in platform.apiLevel = '2.0'

updatePosition

physics.Body:updatePosition(dt)

Updates the position of the body using Euler integration.

Introduced in platform.apiLevel = '2.0'

updateVelocity

physics.Body:updateVelocity(grav, damp, dt)

Updates the velocity of the body using Euler integration.

Introduced in platform.apiLevel = '2.0'

vel

vvel = physics.Body:vel()

Returns the vector velocity of the body.

Introduced in platform.apiLevel = '2.0'

vLimit

vmax = physics.Body:vLimit()

Returns the speed limit of the body.

Introduced in platform.apiLevel = '2.0'

wLimit

wmax = physics.Body:wLimit()

Returns the angular velocity limit of the body. The angular velocity is in radians per unit time.

Introduced in platform.apiLevel = '2.0'

world2Local

lvec = physics.Body:world2Local(wvec)

Converts wvec from world coordinates to body-relative coordinates. Returns the converted vector.

Introduced in platform.apiLevel = '2.0'