Difference between revisions of "B2.createMouseJointDef"
| Line 9: | Line 9: | ||
(table) = b2.createMouseJointDef(bodyA,bodyB,targetx,targety,maxForce,frequencyHz,dampingRatio) | (table) = b2.createMouseJointDef(bodyA,bodyB,targetx,targety,maxForce,frequencyHz,dampingRatio) | ||
</source> | </source> | ||
| − | '''bodyA''': (b2.Body) the first attached body | + | === Parameters === |
| − | '''bodyB''': (b2.Body) the second attached body | + | '''bodyA''': (b2.Body) the first attached body <br/> |
| − | '''targetx''': (number) the x coordinate of the world target point | + | '''bodyB''': (b2.Body) the second attached body <br/> |
| − | '''targety''': (number) the y coordinate of the world target point | + | '''targetx''': (number) the x coordinate of the world target point <br/> |
| − | '''maxForce''': (number) the maximum constraint force that can be exerted to move the candidate body | + | '''targety''': (number) the y coordinate of the world target point <br/> |
| − | '''frequencyHz''': (number, default = 5) the response speed | + | '''maxForce''': (number) the maximum constraint force that can be exerted to move the candidate body <br/> |
| − | '''dampingRatio''': (number, default = 0.7) the damping ratio. 0 = no damping, 1 = critical damping | + | '''frequencyHz''': (number, default = 5) the response speed <br/> |
| + | '''dampingRatio''': (number, default = 0.7) the damping ratio. 0 = no damping, 1 = critical damping <br/> | ||
| + | === Return values === | ||
'''Returns''' (table) A new mouse joint definition table<br/> | '''Returns''' (table) A new mouse joint definition table<br/> | ||
| + | === Examples === | ||
| + | '''Mouse joint'''<br/> | ||
| + | <source lang="lua">--create empty box2d body for joint | ||
| + | local ground = world:createBody({}) | ||
| + | |||
| + | --joint with dummy body | ||
| + | local mouseJoint = nil | ||
| + | |||
| + | -- create a mouse joint on mouse down | ||
| + | function self:onMouseDown(event) | ||
| + | local jointDef = b2.createMouseJointDef(ground, body, event.x, event.y, 100000) | ||
| + | mouseJoint = world:createJoint(jointDef) | ||
| + | end | ||
| + | |||
| + | -- update the target of mouse joint on mouse move | ||
| + | function self:onMouseMove(event) | ||
| + | if mouseJoint ~= nil then | ||
| + | mouseJoint:setTarget(event.x, event.y) | ||
| + | end | ||
| + | end | ||
| + | |||
| + | -- destroy the mouse joint on mouse up | ||
| + | function self:onMouseUp(event) | ||
| + | if mouseJoint ~= nil then | ||
| + | world:destroyJoint(mouseJoint) | ||
| + | mouseJoint = nil | ||
| + | end | ||
| + | end</source> | ||
Revision as of 11:45, 23 August 2018
Available since: Gideros 2011.6
Description
Creates and returns a mouse joint definition table with the bodies, world target point, maxForce and optional frequencyHz and dampingRatio.
(Please refer to b2.World:createJoint function for more information about all the information needed to create a mouse joint).
(table) = b2.createMouseJointDef(bodyA,bodyB,targetx,targety,maxForce,frequencyHz,dampingRatio)
Parameters
bodyA: (b2.Body) the first attached body
bodyB: (b2.Body) the second attached body
targetx: (number) the x coordinate of the world target point
targety: (number) the y coordinate of the world target point
maxForce: (number) the maximum constraint force that can be exerted to move the candidate body
frequencyHz: (number, default = 5) the response speed
dampingRatio: (number, default = 0.7) the damping ratio. 0 = no damping, 1 = critical damping
Return values
Returns (table) A new mouse joint definition table
Examples
Mouse joint
--create empty box2d body for joint
local ground = world:createBody({})
--joint with dummy body
local mouseJoint = nil
-- create a mouse joint on mouse down
function self:onMouseDown(event)
local jointDef = b2.createMouseJointDef(ground, body, event.x, event.y, 100000)
mouseJoint = world:createJoint(jointDef)
end
-- update the target of mouse joint on mouse move
function self:onMouseMove(event)
if mouseJoint ~= nil then
mouseJoint:setTarget(event.x, event.y)
end
end
-- destroy the mouse joint on mouse up
function self:onMouseUp(event)
if mouseJoint ~= nil then
world:destroyJoint(mouseJoint)
mouseJoint = nil
end
end
