Difference between revisions of "B2.World:step"
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__NOTOC__ | __NOTOC__ | ||
| − | '''Available since:''' Gideros 2011.6<br/> | + | <languages /> |
| − | === Description === | + | '''<translate>Available since</translate>:''' Gideros 2011.6<br/> |
| − | + | '''<translate>Class</translate>:''' [[Special:MyLanguage/b2.World|b2.World]]<br/> | |
| − | + | ||
| − | + | === <translate>Description</translate> === | |
| − | < | + | Takes a time step. This performs collision detection, integration, and constraint solution. |
| − | + | <syntaxhighlight lang="lua"> | |
| − | </ | + | b2.World:step(timeStep,velocityIterations,positionIterations) |
| − | '''timeStep | + | </syntaxhighlight> |
| − | '''velocityIterations | + | |
| − | '''positionIterations | + | === <translate>Parameters</translate> === |
| + | '''timeStep''': (number) <translate>the amount of time to simulate, this should not vary</translate> <br/> | ||
| + | '''velocityIterations''': (number) <translate>for the velocity constraint solver</translate> <br/> | ||
| + | '''positionIterations''': (number) <translate>for the position constraint solver</translate> <br/> | ||
| + | |||
| + | === <translate>Examples</translate> === | ||
| + | '''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) | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | {{B2.World}} | ||
Latest revision as of 14:27, 13 July 2023
Available since: Gideros 2011.6
Class: b2.World
Description
Takes a time step. This performs collision detection, integration, and constraint solution.
b2.World:step(timeStep,velocityIterations,positionIterations)
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
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)
