Remove object on touch

SPDApps · January 2012

hi im new to this could someone tell me how to remove a box2d object on touch thanks

atilim · January 2012

Hi,

You need:
1. destroy body with b2.World:destroyBody and
2. remove the sprite from stage with Sprite:removeChild

SPDApps · January 2012

Ooooh thanks

SPDApps · January 2012

um i cant figure out how to do it could you show me a code example?

GregBUG · January 2012

 
stage:addEventListener(Event.TOUCHES_BEGIN , onTouchesBegin)
 
function onTouchesBegin(event)
	world:destroyBody(yourObjectBody)
	stage:removeChild(yourObjectSprite)
end

add event listner to the stage...

then in onTouchesBegin function (fired only when you touch the screen of you device)
remove the bodyobject and the relative sprite...

hope it helps.

Ciao Gianluca.

atilim · January 2012

Open "Sleeping bodies" example at Physics section and add these to the end of main.lua:

local function onMouseDown(event)
	for i=1,stage:getNumChildren() do
		local sprite = stage:getChildAt(i)
		local body = sprite.body
		if sprite:hitTestPoint(event.x, event.y) then
			stage:removeChild(sprite)
			world:destroyBody(body)
			break
		end
	end
end
 
stage:addEventListener(Event.MOUSE_DOWN, onMouseDown)

atilim · January 2012

ahoy GregBUG! :ar!

GregBUG · January 2012

yes... atilim example is much better... :P

because"Event.TOUCHES_BEGIN" work only on device not in the pc... ;;)

ciao ciao

Gianluca.

atilim · January 2012

I think both are informative

SPDApps · January 2012

thanks guys [-O<

paulseau · September 2013

Hi all. Atilim, I put this
"local function onMouseDown(event)
for i=1,stage:getNumChildren() do
local sprite = stage:getChildAt(i)
local body = sprite.body
if sprite:hitTestPoint(event.x, event.y) then
stage:removeChild(sprite)
world:destroyBody(body)
break
end
end
end

stage:addEventListener(Event.MOUSE_DOWN, onMouseDown)"

to Sleeping Bodies as you said. It doesn't work and shows the following message:
"main.lua:90: bad argument #1 to 'destroyBody' (b2Body expected, got nil)
stack traceback: main.lua:90: in function

"

What could be wrong here? I stuck with the same think in my project.
Thanks.

ar2rsawseen · September 2013

@paulseau it seems not all stage elements has bodies, so you would also need to check for body, as

local function onMouseDown(event)
	for i=1,stage:getNumChildren() do
		local sprite = stage:getChildAt(i)
		local body = sprite.body
		if sprite:hitTestPoint(event.x, event.y) and body then
			stage:removeChild(sprite)
			world:destroyBody(body)
			break
		end
	end
end
 
stage:addEventListener(Event.MOUSE_DOWN, onMouseDown)

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