B2.World:step
Available since: Gideros 2011.6
Class: b2.World
Description
Takes a time step. This performs collision detection, integration, and constraint solution. <syntaxhighlight lang="lua"> b2.World:step(timeStep,velocityIterations,positionIterations) </source>
Parameters
timeStep: (number) the amount of time to simulate, this should not vary
velocityIterations: (number) for the velocity constraint solver
positionIterations: (number) for the position constraint solver
Examples
Creating Box2d body and moving Bitmap along the body <syntaxhighlight lang="lua"> require "box2d" local world = b2.World.new(0, 10, true)
--create ball bitmap object from ball graphic local ball = Bitmap.new(Texture.new("ball.png")) --reference center of the ball for positioning ball:setAnchorPoint(0.5,0.5)
ball:setPosition(100,100)
--get radius local radius = ball:getWidth()/2
--create box2d physical object local body = world:createBody{type = b2.DYNAMIC_BODY} local circle = b2.CircleShape.new(0, 0, radius) local fixture = body:createFixture{shape = circle, density = 1.0, friction = 0.1, restitution = 0.2} ball.body = body
--add to scene stage:addChild(ball)
stage:addEventListener(Event.ENTER_FRAME, function() -- edit the step values if required. These are good defaults!
world:step(1/60, 8, 3)
ball:setPosition(ball.body:getPosition()) ball:setRotation(math.rad(ball.body:getAngle())) end) </source>
