OOP Understanding

[Drakk]

Hey everyone,
I'm new to love, and lua in general. I love it so far.
I read alot of topics on here about OOP, and this isn't a love specific question but it seems it's a common topic, and I have an issue.

I'm using Bart's class lib. Here ( removed license for the sake of code length )

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__HAS_SECS_COMPATIBLE_CLASSES__ = true

local class_mt = {}

function class_mt:__index(key)
    return self.__baseclass[key]
end

class = setmetatable({ __baseclass = {} }, class_mt)

function class:new(...)
    local c = {}
    c.__baseclass = self
    setmetatable(c, getmetatable(self))
    if c.init then
        c:init(...)
    end
    return c
end

I also created this small sound manager thing, to see if I'm using this correctly.

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--[[

@File: sound.lua
@Purpose:
--------------------------------------------------------

]]--

ZLove.Sound = {};
ZLove.Sound.internalObjects = {}; -- container full of sound objects
ZLove.Sound.Object = class:new();

function ZLove.Sound.Object:init( Source, sType, bPrecache )
	
	bPrecache = bPrecache or false;
	
	self.loveSource = {};
	self.bPrecache = bPrecache;
	self.bPlayed = false;
	
	if( type( Source ) == "table" ) then 
	
		-- if we precache, we load all the sounds in the table
		if( bPrecache ) then
			for _, v in ipairs( Source ) do
				table.insert( self.loveSource, { v, love.audio.newSource( v, sType ) } );
			end
		else
			local iRndIndex = math.random( 1, #Source );
			table.insert( self.loveSource, { Source[ iRndIndex ], love.audio.newSource( Source[ iRndIndex ], sType ) } );
		end
	else
		table.insert( self.loveSource, { Source, love.audio.newSource( Source, sType ) } );
	end
	
	table.insert( ZLove.Sound.internalObjects, self );
	
end

function ZLove.Sound.Object:play()
	self.loveSource[1][2]:play();
end

function ZLove.Sound:update( dt )
	
	-- now we can loop through self.internalObjects
	-- and control every sound object we've created
	
end

I use it like so:

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local nSound = ZLove.Sound.Object:new( "sound.ogg", "static", false );
nSound:play();

I keep all the created objects inside ZLove.Sound.internalObjects, this is so I can loop through the created objects and manage them. Such as deleting them when they're stopped and so on.. I assume i'm using this class lib correctly? Anything part of ZLove.Sound.Object will be 'inherited' by each object I create. Which to my understanding is a good thing, so i don't have to re-write code for each sound I make?

Sorry if I wasn't to clear. This all works, but I'm not sure if i'm using OO abilities correctly.

Thanks!

[sanjiv]

I can't help, but this is exactly the kind of stuff I need to approach next. So now that I've posted here, it'll be easy for me to return to.

Related question: How does one go about choosing an OOP library? Is the following list kept up to date? https://www.love2d.org/wiki/Category:Libraries

[scutheotaku]

I'm not familiar with SECS in particular, but yes it appears that you are using OO correctly

As a side note, "table.insert" can be slow. So instead of this (for example):

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table.insert( self.loveSource, { v, love.audio.newSource( v, sType ) } );

...you may want to use something like this instead:

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self.loveSource[#self.loveSource + 1] = { v, love.audio.newSource( v, sType ) }

--table.insert(myTable, value)
--does the same thing as
--myTable[#myTable+1] = value

[not a plug>>>]It may be helpful for you to look at my LOVE project framework with OO: https://www.love2d.org/forums/viewtopic ... 38&p=73277 It is based on the 30log library, but you may find some of the functions and methods (particularly the ones in Entity.lua) useful to you

Related question: How does one go about choosing an OOP library? Is the following list kept up to date? https://www.love2d.org/wiki/Category:Libraries

I suggest just that you just look over them and to go with the one that has the features you need and best fits your style. It's also worth looking at other users' comments, as a few of the OO libraries have inheritance problems (though that may not be a big deal for your project).

MiddleClass ( https://www.love2d.org/wiki/MiddleClass ) and SECS ( https://www.love2d.org/wiki/Simple_Educ ... ass_System ) seem to be the most popular choices. I'm partial to 30log ( https://www.love2d.org/wiki/30log ) as it's really simple and easy to use, yet is very powerful (to see how easy it is, see "quick tour" here: https://github.com/Yonaba/30log/blob/master/README.md ).

Also, there's always the option of writing your own OO code. This should be a good start (assuming you know the fundamentals of Lua, that is): http://www.lua.org/pil/16.html

PS: If either of you need an explanation of OOP in general, here's a really good one: http://teknadesigns.com/what-is-object- ... ogramming/

[Drakk]

scutheotaku, great post. Thank you, helped alot.

[scutheotaku]

scutheotaku, great post. Thank you, helped alot.

Great! I'm glad I could help