LÖVE

Sir_Silver wrote: ↑Sun Aug 27, 2017 1:44 am Don't have the time to explain the many ways you could do that at the moment, but here is some example code that you might be able to understand.

Code: Select all

local entity = {
    w = 50,
    h = 50,

    color = {255, 0, 0}
}

entity.__index = entity

function entity:draw()
    love.graphics.setColor(self.color)
    love.graphics.rectangle("fill", self.x, self.y, self.w, self.h)
end

local entities = {}

function love.draw()
    for i = 1, #entities do
        entities[i]:draw()
    end
end

function love.mousepressed(x, y)
    local entity = setmetatable({}, entity)
    entities[#entities + 1] = entity

    entity.x, entity.y = x, y
end

Sir_Silver wrote: ↑Sun Aug 27, 2017 1:58 am Yeah, so in the function love.draw, we aren't writing hundreds of lines of code to draw each individual thing we want to draw, instead, we iterate over a table which contains all of the things we want to draw (which could be anywhere from 0 to a million or more things).

The for loop inside of love.draw calls the "draw" function for each one of the entities:

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function entity:draw()
    love.graphics.setColor(self.color)
    love.graphics.rectangle("fill", self.x, self.y, self.w, self.h)
end

Notice that love.graphics.rectangle doesn't take hard coded arguments, instead it uses variables that are stored on the self. The self.x and self.y variables of the entity are given during the love.mousepressed callback:

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function love.mousepressed(x, y)
    local entity = setmetatable({}, entity)
    entities[#entities + 1] = entity

    entity.x, entity.y = x, y
end

This creates an "instance" of an entity, stores the instance of an entity inside of the entities table (which we use for drawing all of the entities in love.draw), and finally gives the entity the necessary x and y variable for determining where to draw it.

I don't have time to proofread this right now, so I'll edit later if it's wrong, let me know if this helps! =)

xNick1 wrote: ↑Sun Aug 27, 2017 6:43 am With # you calculate the length of the table. When you create a new element you want to create it as the last element in the table. So #table +1.
Metatables are needed for oop.
Like self.x, self.y.
Just check them out!

Sir_Silver wrote: ↑Tue Aug 29, 2017 1:31 am When you try to access an index of a table whose value is nil,, if that table has a metatable which has an __index metamethod, it will invoke the __index metamethod. Here's what happens without the use of a metatable:

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local my_table = {}
print(my_table[1])  --prints nil, because there is no value at index 1

However, if we set the metatable of my_table to a table that has an __index metamethod, something different will happen:

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local my_metatable = {
	1
}

function my_metatable.__index(t, k)
	print("You have just used __index metamethod")
	return rawget(my_metatable, k)	
end

local my_table = setmetatable({}, my_metatable)
print(my_table[1])  --[[
	prints out: 
	You have just used __index metamethod	
	1	
]]

In this example, we try to print out the value of my_table[1]. There is no value there - it is nil - so it checks if my_table has a metatable.
It does have a metatable, so it checks if it has a __index metamethod which it does have, and then calls that function.

In this example, the __index metamethod prints out, "You have just used __index metamethod", and then returns whatever value is inside
the my_metatable table at the same index that was nil for the table we originally tried to index.

It is worth noting that

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local my_metatable = {
	1
}

function my_metatable.__index(t, k)
	return rawget(my_metatable, k)	
end

Is functionally the same as

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local my_metatable = {
	1
}

my_metatable.__index = my_metatable

Btw, I admire you for being self taught. I had the luxury of being taught nearly 1-on-1 for nearly two years. I'm here to to answer any more questions or help you out if you need it.