## creating new objects when needed

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minkzilla
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### creating new objects when needed

I am new to love2d and Lua in general, but so far am loving it! but I have run into a problem that I can not find the answer googling, any help would be greatly appreciated.

So what I am trying to do is create a new enemy (boxes right now) every time you get to a certain point. The problem is I have no idea how to keep making more enemies when ever they are needed, besides just making a ton of rectangles and keep them off screen until needed.

bartbes
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### Re: creating new objects when needed

It depends on how you create those rectangles. Typically though you've got a table that's basically just a list of rectangles, who are themselves tables. At that point you can simply insert a new entry into the list that represents the new rectangle, and suddenly you've got an extra rectangle.

minkzilla
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Joined: Sun Apr 27, 2014 4:08 pm

### Re: creating new objects when needed

bartbes wrote:It depends on how you create those rectangles. Typically though you've got a table that's basically just a list of rectangles, who are themselves tables. At that point you can simply insert a new entry into the list that represents the new rectangle, and suddenly you've got an extra rectangle.
this doesn't really help me very much, could you be more specific please?

I tried this, but I am obviously doing something wrong becasue the rectangle won't even show up. Also how do you control the movement of every rectangle separately, do you just make variables for all of the rectangles in the same way you make the rectangles?

szmol96
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Location: Horvátkút, Hungary

### Re: creating new objects when needed

First of all, you have to create a table, like this:

Code: Select all

enemies = { }
I assume you can handle player positions, x and y. Then you would check if the player is at a certain position.

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if player.x == something and player.y == something then
--do something
end
or

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if player.x > something and player.y > something then
--do something
end
or

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if player.x > something and player.x < something and player.y > something and player.y < something then
--do something
end
And then you can replace the "do something"s with the actual code, specifically you insert an object into the enemies table, like this:

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table.insert(enemies, {
x = somewhere,
y = somewhere
})
You have to replace the "somewhere"s with your desired positions. As for controlling every enemy seperately, you can use a for loop. You should use this in love.update. Don't forget to include dt.

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function love.update(dt)
local i, o
for i, o in ipairs(enemies) do
o.x = o.x + 10 * dt
o.y = o.y + 10 * dt
end
end
And if your enemies do not show up, the main reason may be that you are not drawing them. So, you should use love.draw.

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function love.draw()
local i, o
for i, o in ipairs(enemies) do
love.graphics.draw(the image of the enemy, o.x , o.y)
end
end
I hope this helps. Ask if you have any problems and I will see what i can do about it.
All your code are belong to us.

minkzilla
Prole
Posts: 7
Joined: Sun Apr 27, 2014 4:08 pm

### Re: creating new objects when needed

I am getting the rectangle to spawn. But it goes away when I am not in collision with the area, and likewise it does not move.

thanks for you help btw.

szmol96
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Posts: 51
Joined: Mon Oct 07, 2013 4:24 pm
Location: Horvátkút, Hungary

### Re: creating new objects when needed

Of course it goes away if you left

Code: Select all

o.x = o.x + 10 * dt
o.y = o.y + 10 * dt
as it was.
All your code are belong to us.

minkzilla
Prole
Posts: 7
Joined: Sun Apr 27, 2014 4:08 pm

### Re: creating new objects when needed

How would i get it to stay than?

szmol96
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Posts: 51
Joined: Mon Oct 07, 2013 4:24 pm
Location: Horvátkút, Hungary

### Re: creating new objects when needed

Just don't change the the positions. I only wrote that code to show an example how to change the position of your enemies. If you don't want them to move, delete those two lines.
All your code are belong to us.

minkzilla
Prole
Posts: 7
Joined: Sun Apr 27, 2014 4:08 pm

### Re: creating new objects when needed

sorry, realized I worded that the wrong way.

What I wanted to say was how would I get the enemy to stay spawned even after I left the area that initially spawns it.

szmol96
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Posts: 51
Joined: Mon Oct 07, 2013 4:24 pm
Location: Horvátkút, Hungary

### Re: creating new objects when needed

Leaving the area that spawns the enemy doesn't despawn it.
All your code are belong to us.

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