Collision and Touch Detection Issue

johannastephen · April 22, 2014, 8:22am

Hi, i have a problem with my code. i want to disable touching for an object when the object collide with another object. but when i execute the code, it reports a lot of collision and it idoesn’t response any more. :wacko: for any other button or touching event. Thanks.

Code is here:

&nbsp;object1 = display.newImage("tire2.png", centerX, 500) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;object1.myName = "object1" &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;object1.bodyType = "dynamic" &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;object1.isBullet = true &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;physics.addBody( object1, { density=0.9, friction=0.5, bounce=0.6, radius=60 } ) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; object1.isSleepingAllowed = false &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; object1:addEventListener( "touch", dragBody ) &nbsp; &nbsp; object2 = display.newImage("tire3.png", centerX-centerX/2-180, 500) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;object2.myName = "object2" &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;object2.bodyType = "dynamic" &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;object2.isBullet = true &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;physics.addBody( object2, { density=0.9, friction=0.5, bounce=0.6, radius=60 } ) &nbsp; &nbsp; &nbsp; &nbsp; object2.isSleepingAllowed = false &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; object2:addEventListener( "touch", dragBody ) &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; button = display.newImage("button.png", 145,145) &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;button.anchorX = 1 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;button.anchorY = 0 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;button.x = \_W-52 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;button.y =72.5 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;button.myName = "button" &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; function collision1 (event) &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if ( event.phase == "began" ) then &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; if (event.object1.myName &nbsp;== "object1" and &nbsp;event.object2.myName == "object2" ) then &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;print (event.object1.myName .." &nbsp;and &nbsp;" .. event.object2.myName ) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; object2:removeEventListener( "touch", dragBody )&nbsp; &nbsp; &nbsp; end&nbsp; &nbsp; &nbsp; &nbsp; end&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; end &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; function buttonfunc(event) &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;if event.phase == "ended" then &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; message = display.newText( "Button pressed.", 0, 0, "ContenuBook-Display", 40 ) &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; end &nbsp; &nbsp; &nbsp; end &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp;Runtime:addEventListener( "collision", collision1) &nbsp; &nbsp; &nbsp;button:addEventListener("touch", buttonfunc)

johannastephen · August 7, 2014, 1:48pm

Is there anyone for help???

The_Lemon · August 7, 2014, 8:44pm

hmm sometimes, due to imperfections in the box 2d library you cant perform complex actions within a collision listener function, use a short timer.performwithdelay with a 32 millisecond or less delay eg.

&nbsp; local function collision1 (event) &nbsp;&nbsp; &nbsp; &nbsp; if ( event.phase == "began" ) then &nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (event.object1.myName &nbsp;== "object1" and &nbsp;event.object2.myName == "object2" ) then &nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; timer.performWithDelay(32, function(event) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; print (event.object1.myName .." &nbsp;and &nbsp;" .. event.object2.myName ) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; object2:removeEventListener( "touch", dragBody ) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end,1) &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end&nbsp; &nbsp;&nbsp;&nbsp; end&nbsp; end &nbsp;

Hope this helps, Regards Lemon

johannastephen · August 20, 2014, 4:39pm

Thanks bro. i tried it but i didnt work. Do you have any suggestions?

bjsorrentino · August 20, 2014, 9:32pm

Hi @johannastephen,

Are you getting any error messages in the console? Have you carefully checked the scope of all variables/functions?

Also, just FYI, you must always set physics properties like “.isBullet” after you create the body. If you attempt this before the object is made physical, Corona will not understand what you’re trying to do (well, Lua will just create that property on the object, but it won’t be regarded as a physics-related property).

Brent

johannastephen · August 21, 2014, 2:18pm

No i dont get any error message in the console. only collision events. when i try to remove event listener with or without timer.performWithDelay , it doesnt response any touch. should i change “isBullet” position?

bjsorrentino · August 21, 2014, 8:21pm

There’s likely a scope issue, in how/where you’ve declared your objects and functions, so Lua doesn’t understand what you’re trying to do when you remove the listener (it can’t find it in the proper scope, for example). You should focus on making your objects local, not global, and then ensuring that scope is 100% correct across the entire routine. If you’re somewhat new to Lua, then you should watch this video on scope:

http://www.youtube.com/watch?v=2ATlcGP2zMY

Take care,

Brent

johannastephen · August 22, 2014, 7:02pm

i found the solution with this: i create a counter that detects collision events counts. and when event counts become a lot, i stop the function.

johannastephen · August 7, 2014, 1:48pm

Is there anyone for help???

The_Lemon · August 7, 2014, 8:44pm

hmm sometimes, due to imperfections in the box 2d library you cant perform complex actions within a collision listener function, use a short timer.performwithdelay with a 32 millisecond or less delay eg.

&nbsp; local function collision1 (event) &nbsp;&nbsp; &nbsp; &nbsp; if ( event.phase == "began" ) then &nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (event.object1.myName &nbsp;== "object1" and &nbsp;event.object2.myName == "object2" ) then &nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; timer.performWithDelay(32, function(event) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; print (event.object1.myName .." &nbsp;and &nbsp;" .. event.object2.myName ) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; object2:removeEventListener( "touch", dragBody ) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end,1) &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end&nbsp; &nbsp;&nbsp;&nbsp; end&nbsp; end &nbsp;

Hope this helps, Regards Lemon

johannastephen · August 20, 2014, 4:39pm

Thanks bro. i tried it but i didnt work. Do you have any suggestions?

bjsorrentino · August 20, 2014, 9:32pm

Hi @johannastephen,

Are you getting any error messages in the console? Have you carefully checked the scope of all variables/functions?

Also, just FYI, you must always set physics properties like “.isBullet” after you create the body. If you attempt this before the object is made physical, Corona will not understand what you’re trying to do (well, Lua will just create that property on the object, but it won’t be regarded as a physics-related property).

Brent

johannastephen · August 21, 2014, 2:18pm

No i dont get any error message in the console. only collision events. when i try to remove event listener with or without timer.performWithDelay , it doesnt response any touch. should i change “isBullet” position?

bjsorrentino · August 21, 2014, 8:21pm

There’s likely a scope issue, in how/where you’ve declared your objects and functions, so Lua doesn’t understand what you’re trying to do when you remove the listener (it can’t find it in the proper scope, for example). You should focus on making your objects local, not global, and then ensuring that scope is 100% correct across the entire routine. If you’re somewhat new to Lua, then you should watch this video on scope:

http://www.youtube.com/watch?v=2ATlcGP2zMY

Take care,

Brent

johannastephen · August 22, 2014, 7:02pm

i found the solution with this: i create a counter that detects collision events counts. and when event counts become a lot, i stop the function.