Using "this" in a function rather than a variable name. Also help with game logic

[sebastianflores]

I am not sure how to approach this with Corona, I am trying to make circles fall from the top of the screen and then let users click on them to make them disappear.

The way I would roughly do it in a browser game would be to loop through a block of code that spawns a circle then give it a class name, so every circle has the same class name, then I would create a touch listener that would interact with that class, then use “this” to only allow it to effect the circle that was touched.

If this possible with corona? Can I use “this” instead of a variable name? 

Also is object:setFillColor() a Graphics 2.0 thing only now? I made some stuff a while back and remember it as being a non graphics 2.0 thing but I could be wrong.

[roaminggamer]

@sebastian,

There is not ‘this’ in Lua, but there is a variable referred to as ‘self’.

Please examine this code to see how it can be used.

-- 1. Explicit 'self' local function ex1() -- a. Create Table local aTable = {} aTable.myName = "bob" -- b. Attach a function with explicit 'self' aTable.doit = function( self ) print(self.myName) end -- Call the function and explicitly pass table reference aTable.doit( aTable ) -- Call the function and automatically pass table reference aTable:doit( ) end -- 2. Implicit 'self' local function ex2() -- a. Create Table local aTable = {} aTable.myName = "bill" -- b. Attach a method with implicit 'self' function aTable:doit() print(self.myName) end -- Call the function and explicitly pass table reference aTable.doit( aTable ) -- Call the function and automatically pass table reference aTable:doit( ) end -- 3. Variation on #1, but use 'me' instead of 'self' local function ex3() -- a. Create Table local aTable = {} aTable.myName = "buddy" -- b. Attach a function with explicit 'self' aTable.doit = function( me ) print(me.myName) end -- Call the function and explicitly pass table reference aTable.doit( aTable ) -- Call the function and automatically pass table reference aTable:doit( ) end

Now run the examples:

ex1() ex2() ex3()

You will see this in the console:

bob bob bill bill buddy buddy

Pay particular attention to the use of dot versus colon notation in my code samples.

[roaminggamer]

Forums Etiquette Suggestion.  

One question per post or you’ll end up getting a thread with only some answers.  

That said here is the answer to your second question:

obj:setFillColor( r, g, b, a ) 

has been around since the start.  The difference is:

• Graphics 1.0 - r/g/b/a used values between 0 and 255
• Graphics 2.0 - r/g/b/a uses values between 0 and 1.0

[roaminggamer]

@sebastian,

There is not ‘this’ in Lua, but there is a variable referred to as ‘self’.

Please examine this code to see how it can be used.

-- 1. Explicit 'self' local function ex1() -- a. Create Table local aTable = {} aTable.myName = "bob" -- b. Attach a function with explicit 'self' aTable.doit = function( self ) print(self.myName) end -- Call the function and explicitly pass table reference aTable.doit( aTable ) -- Call the function and automatically pass table reference aTable:doit( ) end -- 2. Implicit 'self' local function ex2() -- a. Create Table local aTable = {} aTable.myName = "bill" -- b. Attach a method with implicit 'self' function aTable:doit() print(self.myName) end -- Call the function and explicitly pass table reference aTable.doit( aTable ) -- Call the function and automatically pass table reference aTable:doit( ) end -- 3. Variation on #1, but use 'me' instead of 'self' local function ex3() -- a. Create Table local aTable = {} aTable.myName = "buddy" -- b. Attach a function with explicit 'self' aTable.doit = function( me ) print(me.myName) end -- Call the function and explicitly pass table reference aTable.doit( aTable ) -- Call the function and automatically pass table reference aTable:doit( ) end

Now run the examples:

ex1() ex2() ex3()

You will see this in the console:

bob bob bill bill buddy buddy

Pay particular attention to the use of dot versus colon notation in my code samples.

[roaminggamer]

Forums Etiquette Suggestion.  

One question per post or you’ll end up getting a thread with only some answers.  

That said here is the answer to your second question:

obj:setFillColor( r, g, b, a ) 

has been around since the start.  The difference is:

• Graphics 1.0 - r/g/b/a used values between 0 and 255
• Graphics 2.0 - r/g/b/a uses values between 0 and 1.0