.lua:1051: bad argument #-2 to 'insert' (Proxy expected, got nil)

Solar2D General Questions/Discussion
#21

Can you tell me in a basic bullet list of steps what you are trying to do?

It looks like you have an object and you want to add a particle emitter to it, then delete that emitter after 500 ms.  Is that right?

#22

self is an object group containing a weapon bullet image object.

I then create a smoke trail emitter for the bullet with self.bulletTrailEffect

I want to delete the emitter (and everything else bullet related) after 500ms

#23

This would work better:

local function addTrail( obj ) if( obj == nil ) then error("Object is nil") end local emitter = display.newEmitter( ... ) -- fill is your own settings here if( emitter == nil ) then error("Emitter is nil") end -- parent is group obj is in. obj.parent:insert( emitter ) -- No need to track this or cancel it is safe to run even if obj is removed before -- it is called. timer.performWithDelay( 500, function() display.remove( emitter ) display.remove( obj ) end ) end -- later ... local tmp = display.newCircle( 10, 10, 10 ) addTrail( tmp )

Note: This doesn’t include code to make the emitter follow the object if it moves.

#24

This would have the emitter follow the object
 

local function addTrail( obj ) if( obj == nil ) then error("Object is nil") end local emitter = display.newEmitter( ... ) -- fill is your own settings here if( emitter == nil ) then error("Emitter is nil") end -- parent is group obj is in. obj.parent:insert( emitter ) function emitter.enterFrame( self ) if( type(self.removeSelf) ~= "function" ) then Runtime:removeEventListener( "enterFrame", self return elseif( not obj.removeSelf or type(obj.removeSelf) ~= "function" ) then Runtime:removeEventListener( "enterFrame", self return end self.x = obj.x self.y = obj.y end Runtime:addEventListener( "enterFrame", emitter ) -- No need to track this or cancel it is safe to run even if obj is removed before -- it is called. timer.performWithDelay( 500, function() Runtime:removeEventListener( "enterFrame", emitter ) display.remove( emitter ) display.remove( obj ) end ) end -- later ... local tmp = display.newCircle( 10, 10, 10 ) addTrail( tmp )
#25

Thank you for your fast and detailed help roaminggamer!

I wish you a Merry Christmas!

#26

You’re welcome.

Ping back later if there is a problem with this solution. Remember, I don’t run these I just type them, so the ‘brain compiler’ may be faulty.

-Ed

#27

I will rework my code after Christmas based on your code sample.

One more thing: can you please explain why the above newGroup code is wrong in the sample above?

#28

It isn’t 100% wrong, but I wouldn’t feel good encouraging you to continue using the table returned by a timer that way.

I would treat the table returned by performWithDelay() with caution and not as a generic table. (Others may not agree).

The real issue I see is that the variable hierarchy is too deep for the purpose it is serving. You can greatly simplify adding, tracking, and removing emitters.

At the end of the day I suspect either the object you are adding the emitter to is not getting created, OR the emitter is not thus the failed insert.

#29

Great info regarding this. Thank you very much!