Example: DYNAMIC_BODY contact with STATIC_BODY (isSensor=true for STATIC_BODY)

Sush19

Hi!

I've created a DYNAMIC_BODY as Follow:

function MyScene:createMyDynamicBody(x, y) local DB = Bitmap.new(Texture.new("images/DB.png")) DB:setAnchorPoint(0.5, 0.5) DB:setPosition(x,y) local radius = DB:getWidth()/2   local body = self.world:createBody{type = b2.DYNAMIC_BODY, fixedRotation = true} body:setPosition(DB:getX(), DB:getY()) body:setAngle(DB:getRotation() * math.pi/180) local circle = b2.CircleShape.new(0, 0, radius) local fixture = body:createFixture{shape = circle, density = 10, friction = 1.0, restitution = 0.4} fixture:setFilterData({categoryBits = 1, maskBits = 26}) DB.body = body DB.body.type = "DB" self:addChild(DB)   return DB end

And I've created a STATIC_BODY as Follow:

function MyScene:createExtraLife(x, y) local SB = Bitmap.new(Texture.new("images/life.png")) SB:setAnchorPoint(0.5, 0.5) SB:setPosition(x,y) local radius = SB:getWidth()/2   local body = self.world:createBody{type = b2.STATIC_BODY} body:setPosition(SB:getX(), SB:getY()) body:setAngle(SB:getRotation() * math.pi/180) local circle = b2.CircleShape.new(0, 0, radius) local fixture = body:createFixture{shape = circle, density = 10, friction = 1.0, restitution = 0.4, isSensor = true} fixture:setFilterData({categoryBits = 8, maskBits = 17}) SB.body = body SB.body.type = "SB" self:addChild(SB)   return SB end

And onBeingContact Function is as Follow:

function MyScene:onBeginContact(e) --getting contact bodies local fixtureA = e.fixtureA local fixtureB = e.fixtureB local bodyA = fixtureA:getBody() local bodyB = fixtureB:getBody()   if bodyA.type and bodyB.type then if bodyA.type == "DB" and bodyB.type == "SB" then local extraLife for i = 1, #self.extraLife do extraLife = self.extraLife[i] end self:removeChild(extraLife) extraLife = nil elseif bodyB.type == "pumpkin" and bodyA.type == "exLife" then local extraLife for i = 1, #self.extraLife do extraLife = self.extraLife[i] end self:removeChild(extraLife) extraLife = nil end end end

And my init() Function is as Follow:

function MyScene:init() self.DB = self:createMyDynamicBody(200, 300) self.extraLife = {} self.extraLife[#self.extraLife+1] = self:createExtraLife(550, 185) self.extraLife[#self.extraLife+1] = self:createExtraLife(70, 515) self.extraLife[#self.extraLife+1] = self:createExtraLife(200, 400) self.extraLife[#self.extraLife+1] = self:createExtraLife(380, 380)   self:addEventListener(Event.ENTER_FRAME, self.onEnterFrame, self) self.world:addEventListener(Event.BEGIN_CONTACT, self.onBeginContact, self) end

My Question and Problem is that:
First time when I move Dynamic body in contact with the static body it works fine, The static body gets disappear.
But when I move the Dynamic body again to the position where the static body was, that time it again goes inside onBeingContact() as I've removed the static body on the first contact itself, and it throws error saying:

The supplied Sprite must be a child of the caller. stack traceback:<\pre> I want to create many static bodies(eg: many coins or stars or life's etc..) and each time when the dynamic body touches any static body that time only that static body should disappear from the stage permanently and when the dynamic body moves again to the same position where the static body was, it should not go inside onBeingContact()   Can any one help me out for this problem Or any best method to achieve such action   Thank you.. <img class="emoji" src="http://forum.gideros.rocks/resources/emoji/smile.png" title=":)" alt=":)" height="20" />

ar2rsawseen

Simply removing child is not enough, you also need to destroy a body, or at least set it to inactive, like:

if bodyA.type == "DB" and bodyB.type == "SB" then local extraLife for i = 1, #self.extraLife do extraLife = self.extraLife[i] end self:removeChild(extraLife) bodyB:setActive(false) extraLife = nil

Sush19

I tried by setting it to inactive but I'm getting error saying:

World is locked.

As I've many Static bodies, How do I know which Static body was in contact with a Dynamic body on onBeingContact(), Right now when I remove a static body on contact with dynamic body the firstly add Static body gets disappear, although if contact is with lastly added static body in next contact the secondly added static body gets disappear and so on..

ar2rsawseen

firstly add this line to MyScene:createExtraLife

SB.body.object = SB

And then inside collision checking do this:

if bodyA.type == "DB" and bodyB.type == "SB" then bodyB.object:removeFromParent() Timer.delayedCall(1, function() bodyB:setActive(false) --or remove body completely self.world:destroyBody(bodyB) end)

Sush19

Hi,
I tried the above code but I'm getting error

testing.lua:133: bad argument #1 to 'removeChild' (Sprite expected, got no value) stack traceback: testing.lua:143: in function <testing.lua:142>

I've attached the example file...

hgvyas123

try this function

function MyScene:onBeginContact(e) local fixtureA = e.fixtureA local fixtureB = e.fixtureB local bodyA = fixtureA:getBody() local bodyB = fixtureB:getBody()   Timer.delayedCall(1,function() if bodyA.type and bodyB.type then if bodyB.object then bodyB.object:removeFromParent()   bodyB.object = nil bodyB:setActive(false) --or remove body completely self.world:destroyBody(bodyB) end       end end) end

Sush19

Thanks @hgvyas123
Its working now....