ahhhh formatting problem because they use google tools. I am in China behind the great wall of china and when I posted the previous post I was connected to VPN (not working at time). This post was after VPN was working. So, they must use googleapis.com or something for formatting that did not get called when I wrote the previous post without using VPN. So, sorry for the previous mess.
I just tried adding this line
floor:addEventListener(“collision”, CollisionWithLine)
Still no help.
I guess it doesn’t matter which one we listen to. It will just depend which one we want to be object1, right?
event.object1 and event.object2 are only for use with runtime collision listeners. Local collision listeners, which you are using here, use event.target for the object that was hit (i.e. the object that had a collision listener applied to it), and event.other for the object that collided with it.
Thank you SOOO much! That worked perfectly!
I read in there -
When the event is detected with a table listener within an object, certain properties are replaced:
- object1 → target
- object2 → other
- element1 → selfElement
- element2 → otherElement
But, can you explain what a runtime listener is?
Thank you once again!
A runtime listener runs across all objects, waiting for a collision between any two objects. Using a local collision listener allows you to be more targeted in terms of what collisions you do and don’t want to track.
An example would be the rings in Sonic The Hedgehog. When he gets hit and they fly all over the place, you wouldn’t want a listener to be running every time the rings collided with each other or platforms, enemies etc. It would just slow everything down.
So you’d put a local listener on Sonic and say ‘If sonic gets hit by a ring, collect the ring’.
Thank you!
Two more questions if I may bother you.
I am trying to learn destroy method, but having trouble getting it to work. So, for right now, I just made the object invisible.
However, the BIGGER problem I am having is the text inside the circle.
I figured out the immediate collisions were caused by the text being inside the circle.
Which is fine. I fixed it by checking if the id’s were the same I ignored the collisions.
The problem is this…
physics.addBody(c, {density = 0.01, radius = radius, bounce = 0.0})
physics.addBody(text, {density = 0.01, radius = radius, bounce = 0.0})
When the circle hits the bottom it disappears. Great. However, the text has stopped moving because the circle stopped moving (so it won’t hit the floor). I am not able to try to reference the text by its .id
Example I tried using id from c to make text.id invisible but couldn’t do it from inside the listener.
Is there a way to make those 2 things a NEW GROUP. Example: Something like this…
smallGroup:insert©
smallGroup:insert(text)
Then do physics.addBody(smallGroup, …)
I already tried it - didn’t work, but that would be ideal, then I can make the smallGroup invisible and then delete it.
Thanks!
This is the code I tried to destroy the obj
I put this inside function CollisionWithLine(event)
local function removeObject()
display.remove(event.obj)
end
timer.performWithDelay(1, removeObjects, 1)
Yes, you want to make your circle object and text a group, and then make that a physics object. Create your circle and text objects then:
[lua]
local g = display.newGroup()
g:insert©
g:insert(text)
physics.addBody(g, {density = 0.01, radius = radius, bounce = 0.0})
g:addEventListener(“collision”,collisionWithLine)
g.id = choice
g.objective = objective
g.myName = choice
group:insert(g)
[/lua]
In your removal code, you called the function removeObject then called it using removeObjects.
That corrected, the object removal code should work (I think), maybe put a longer delay, say 50ms? And remember to make event.obj = nil.
[lua] VPN not working so let’s see if I can format this response or not.
I am about to pull my hair out! I am trying to learn from what you wrote and run with it. It worked great with the touch event (making the circle and text into g). If I touch one circle that one circle disappears (circle and text)- GREAT! but, for the other event if collision with line then they ALL disappear instantly.
According to messages I print. It appears as though, as soon as the first circle touches the line, then all circles touch the line! So, it is as if g is being done for ALL circles for the collision event instead of different g. Yet, it worked fine for the touch event.
Any ideas? I am not going to post my code, because a) almost identical to above and b) VPN not working so I don’t know if this will format well.
[/lua]
Put the code in the lua tags as I mentioned above, and paste in from your code editor. That will help with the formatting.
[lua] function CollisionWithLine(event) local obj = event.target local cid = obj.id local objective = obj.objective local targ = event.other if ( obj == nil) then print(“nothing in obj”) return false end if ( targ == nil) then print(“nothing in targ”) return false end if targ.myName == obj.myName then print(“Ignore - circle and text hitting each other”) – should no longer happen but did twice out of 100. return false end if event.phase == “began” then if targ.myName == “Floor” then print (“Circle number " … cid … " collided with floor!”) print ("obj1 is " … targ.myName … " obj2 is " … obj.myName) print ("objective is " … objective) – then remove the object after 1 cycle local function removeObject() obj.isVisible = false display.remove(obj) obj = nil end timer.performWithDelay(50, removeObject, 1) end end function touchCircle(event) local obj = event.target local cid = obj.id local objective = obj.objective if event.phase == “began” then print (“Circle number " … cid … " was clicked!”) print ("objective is " … objective) obj.isVisible = false end end then inside my create circle function g:insert© text:setTextColor(0,0,1,255) g:insert(text) physics.addBody(g, {density = 0.01, radius = radius, bounce = 0.0}) g:setLinearVelocity(0,speed) g:addEventListener(“touch”, touchCircle) – to make it touchable g:addEventListener(“collision”, CollisionWithLine) – to make it check if collided. g.id = choice g.objective = objective g.myName = choice [/lua] So, as you can see, the 2 listeners were setup with the same call (using g). Thanks for your help!
well, I thought I would be smart and make an array of g, but even that didn’t matter! SOMETHING crazy is going on. As soon as touched the line all the circles disappeared. Yet, it worked with touch. I can understand if they BOTH didn’t work, but for one to work and the other not?
You need to create a fresh ‘local g’ display group for every circle&text object you create. Otherwise you have one big display group called ‘g’ which contains all the circles and text, so when any element of ‘g’ hits the line, the whole display group is removed.
I think I am doing that. In my createCircle function I have local g = display.newGroup() isn’t that what you are talking about? Plus why would it make the whole display group disappear when it touches a line and not when I click on a circle? It “seems” (in MHO) that it should do both the same way. Thanks!
Can you post all the code?
I made a short project that has everything main.lua [lua] local composer = require “composer” local scene = composer.scene local physics = require(“physics”) physics.start() composer.isDebug = true display.setStatusBar(display.HiddenStatusBar) _W = display.contentWidth _H = display.contentHeight local physics = require “physics” physics.setGravity( 0, 0 ) local function main() composer.gotoScene( “ifc.startPlay” ) end timer.performWithDelay(200,main) [/lua] StartPlay.lua [lua] local composer = require( “composer” ) local scene = composer.newScene() – ----------------------------------------------------------------------------------------------------------------- – All code outside of the listener functions will only be executed ONCE unless “composer.removeScene()” is called. – ----------------------------------------------------------------------------------------------------------------- --local circleGroup = display.newGroup() local circles = {} local texts = {} – “scene:create()” function scene:create( event ) local sceneGroup = self.view print("_W and _H is " … _W … _H ) local floor = display.newImageRect(sceneGroup,“images/floor.png”,_W,2) floor.x=_W/2 floor.y=_H-1 floor.myName=“Floor” floor.id=“Floor” sceneGroup:insert(floor) --physics.addBody(floor, “static”, {isSensor = True}) physics.addBody(floor, “static”) level1b( sceneGroup, 20, 30, 40) math.randomseed( os.time() ) end function level1b( group, objective, speed, points) local created=0 local loop_counter=0 local i=0 local j=0 – worry about points later repeat loop_counter=loop_counter+1 j=math.floor(loop_counter/5) i=loop_counter-j*5 created = created+1 createCircle(group, 60*i+30,-70*j, 28, created, speed, objective) until (created == 100) end function createCircle(group, xCenter, yCenter, radius, created, speed, objective) – I noticed I am not really using this group - is that a problem? local c = display.newCircle(group, xCenter, yCenter, radius) local choice=math.random(1,100000) local text = display.newText(group,choice,xCenter,yCenter,Helvetica, 12) local g = display.newGroup() g:insert© text:setTextColor(0,0,1,255) g:insert(text) physics.addBody(g, {density = 0.01, radius = radius, bounce = 0.0}) g:setLinearVelocity(0,speed) g:addEventListener(“touch”, touchCircle) – to make it touchable g:addEventListener(“collision”, CollisionWithLine) – to make it check if collided. g.id = choice g.myName = choice circles[created]=c texts[created]=text end function touchCircle(event) local obj = event.target local cid = obj.id if event.phase == “began” then print (“Circle number " … cid … " was clicked!”) obj.isVisible = false end end function CollisionWithLine(event) local obj = event.target local cid = obj.id local targ = event.other if event.phase == “began” then if targ.myName == “Floor” then print (“Circle number " … cid … " collided with floor!”) print ("obj1 is " … targ.myName … " obj2 is " … obj.myName) obj.isVisible = false – then remove the object after 50 cycles – local function removeObject() – took this out to show objects going invisible enough for this demo. – obj.isVisible = false – display.remove(obj) – obj = nil – end – timer.performWithDelay(50, removeObject, 1) end end end – “scene:show()” function scene:show( event ) local sceneGroup = self.view local phase = event.phase if ( phase == “will” ) then – Called when the scene is still off screen (but is about to come on screen). elseif ( phase == “did” ) then – Called when the scene is now on screen. – Insert code here to make the scene come alive. – Example: start timers, begin animation, play audio, etc. end end – “scene:hide()” function scene:hide( event ) local sceneGroup = self.view local phase = event.phase if ( phase == “will” ) then – Called when the scene is on screen (but is about to go off screen). – Insert code here to “pause” the scene. – Example: stop timers, stop animation, stop audio, etc. elseif ( phase == “did” ) then – Called immediately after scene goes off screen. end end – “scene:destroy()” function scene:destroy( event ) local sceneGroup = self.view – Called prior to the removal of scene’s view (“sceneGroup”). – Insert code here to clean up the scene. – Example: remove display objects, save state, etc. end – Listener setup scene:addEventListener( “create”, scene ) scene:addEventListener( “show”, scene ) scene:addEventListener( “hide”, scene ) scene:addEventListener( “destroy”, scene ) return scene [/lua]
Try adding sceneGroup:insert(g) at the bottom of createCircle.
Tried. 
Didn’t work.
Strange one. I won’t be back in front of my dev machine for a few hours, I can try running the code then.
Thanks. That is why I tore everything else out and worked on these pieces only. It just appears to me that the groups are being treated differently by the touch and the collusion. Appreciate any assistance you can give me. Thanks!