So i created a function that creates a ship, but now I want to create multiple ships depending on what the score is. How do I create more instances of the same object?
I created a table ship{} but I don’t know how to assign each instance their name i.e. ship1, ship2 and have it assign automatically the first name available since some of them get destroyed and removed by removeSelf() command.
I’ve been using a simple Class type structure so you could have something like this in Ship.lua:
module(..., package.seeall)
function new(x, y)
local self = display.newImage("ship.png", x, y)
function self:fire()
print("Fire!")
end
return self
end
and then in your main.lua file (or anywhere else), just have:
local ship = require("Ship")
local ships = {}
local ship1 = ship.new(10, 10)
local ship2 = ship.new(40, 40)
ships[#ships + 1] = ship1
ship1.name = "Ship" .. #ships
ships[#ships + 1] = ship2
ship2.name = "Ship" .. #ships
As for respawning in general, rather than removing them explicitly like that I would just have a pool of ship objects that have already been killed (that aren’t removed, just hidden) then you can just reactivate them as needed rather than constantly creating and destroying things.
Hopefully this answer will be of some use however it is kind of rushed as I have to be somewhere, if it didn’t help just say and I will try to help further. [import]uid: 5833 topic_id: 1873 reply_id: 5523[/import]
This is adding an element (in this case, the ship1 table) into the ships table.
Specifically this bit #ships + 1 is saying to place it at the index of whatever the current count of items in the table is (at the beginning this is 0) plus 1. It would be the same as doing this:
ships[1] = ship1
ships[2] = ship2
Then this second line: ship1.name = "Ship" .. #ships is setting an element in the ship1 table (called “name”) to the value of “Ship” and whatever the count of items in the ships array, again this is the same as saying this:
ship1.name = "Ship1"
ship1.name = "Ship2"
Finally, this line module(..., package.seeall) is placed at the top of external modules ( so in this case, “ship.lua”) and I believe that it is setting the metadata of the module so that it inherits stuff from global, however I am not entirely sure on this (will need to ask someone more in the know). I know it is needed though
Hopefully that clears some stuff up, if not just ask again.
Ok I am having problems implementing this. I have multiple ships flying and when they crash on the ground I need to spawn the graphic of the crater left by the crash.
so I have the following code
craters={}
local spawnCrater = function ()
i=craters[#craters+1]
crater[i] = sprite.newSprite (craterSet)
crater[i]:prepare("Glowing")
crater[i]:play("Glowing")
It doesn’t seem to work. What I am trying to do is when the crash happens, create a new instance of the crater and give it the next available number. I need to be able to remove that as well after a while.
The method that you mentioned about creating and hiding instances works well and I am using it for the ships, since I know how many total ships I can have at a time on the screen but in this case I could have an unknown number of craters.
local craters = {}
local spawnCrater = function(x, y)
local craterIndex = #craters + 1
local newCrater = sprite.newSprite(craterSet)
newCrater.x = x
newCrater.y = y
newCrater:prepare("Glowing")
newCrater:play("Glowing")
craters[craterIndex] = newCrater
end
local getCrater = function(index)
return craters[index]
end
local getCraterCount = function()
return #craters
end
As for the removing of them, you could still use two separate lists. One for active and one for deactivated craters.
local activeCraters = {}
local inactiveCraters = {}
local getCrater = function(x, y)
if(#inactiveCraters \> 0) then -- There are craters in the inactive list so reactivate them
local crater = table.remove(inactiveCraters)
activeCraters[#activeCraters + 1] = crater
crater.x = x
crater.y = y
crater.isVisible = true
return crater
else -- There aren't any spare deactivated ones, so create a new one
local crater = spawnCrater(x, y)
activeCraters[#activeCraters + 1] = crater
return crater
end
end
local destroyCrater = function(index)
local crater = table.remove(activeCraters, index)
crater.isVisible = false
inactiveCraters[#inactiveCraters + 1] = crater
end
This code may not be perfect as I haven’t checked it, but it should work (in theory )
Hope it helps. [import]uid: 5833 topic_id: 1873 reply_id: 5548[/import]
So my problem now is that all my functions are not localized to the instance but they are distributed across or usually to another instance. Say if I do something to one ship like destroying it, it actually destroys the first one created. Same for the craters. [import]uid: 8192 topic_id: 1873 reply_id: 5567[/import]
That sounds about right yes, I try to go as much OO (well, as OO as I can make it anyway with Lua) as possible but that’s just how I like it. Everyone’s coding style is different so my methods may not be right for you. [import]uid: 5833 topic_id: 1873 reply_id: 5574[/import]
