Programming Problem

iWatts · June 2014

Im trying to get fires to be added randomly to this building. I want a new fire to randomly spawn, and fires vanish after 4 seconds. Please explain how I could do this using simply methods, in only one main lua. Here is some sample code for how i plan to do it:

-- Create Timer
local messageTimer = Timer.new(4000)
-- Timer Function
function tick(event)
messageTimer:start()
AddFire = math.random(12)

flames[AddFire]:setVisible(true)
end

I want to use a timer, and every 4000 miliseconds ( 4 seconds) a flame is added or something)
thanks for the help!

ar2rsawseen · June 2014

Sorry, but I don't understand where is your problem?
Something like this should work:

function spawnFire()
    local fire = Bitmap.new(Texture.new("fire.png", true))
    fire:setPosition(math.random(0, 800), math.random(0, 400))
    stage:addChild(fire)
    Timer.delayedCall(4000, function()
        fire:removeFromParent()
    end)
end

Now you only need to determine the position where to spawn the fire, not simple random, but probably on windows, only right?

And you can call this method based on how often you want to spawn fires, for example, every 5 seconds

local timer = Timer.new(5000)
timer:addEventListener(Event.TIMER,  spawnFire)
timer:start()

iWatts · June 2014

I sent you a PM to continue the conversation.
Thanks for the help!

talis · June 2014

Actually forums are places to share information so if it is not confidential information(like source code vs vs..) we prefer to write the problems and answers in here, not in private PMs

ar2rsawseen · June 2014

So here is what I would do:

--coordinates where sprites can appear
local coords = {}
coords[1] = {x=100, y = 100}
--etx
Fire = Core.class(Sprite)
 
function Fire:init()
    --pool of fires
    self.pool = {}
 
    --taken coordinates
    self.coords = {}
 
    --spawn frequency
    self.spawnRate = 1000
    self.counter = 0
 
    --add listeners
    self:addEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
    self:addEventListener(Event.REMOVED_FROM_STAGE, self.onRemoved, self)
end
 
function Fire:spawn()
    --first get fire from pool or create new
    local fire
    if #self.pool > 0 then
        -- get from the pool
        fire = table.remove(self.pool)
    else
        --create new
        fire = Bitmap.new(Texture.new("fire.png", true))
        fire:setAnchorPoint(0.5, 0.5)
 
        --add event listener
        fire:addEventListener(Event.MOUSE_DOWN, function(e)
            if fire:hitTestPoint(e.x, e.y) then
                e:stopPropagation()
                self:removeFire(fire, true)
            end
        end)
 
    end
 
    --then find suitable coordinates
    local available = {}
    for i = 1, coords do
        --if not already taken
        if not self.coords[i] then
            table.insert(available, i)
        end
    end
 
    --get random coordinates from available ones
    local ind = available[math.random(#available)]
 
    --store index as reference to fire
    fire.ind = ind
 
    --set fire to coordinates
    fire:setPosition(coords[ind].x, coords[ind].y)
 
    -- store coordinates as taken
    self.coords[ind] = true
 
    --eliminate fire after time period between 4 and 5 seconds
    Timer.delayedCall(math.random(4000, 5000), function()
        self:removeFire(fire, false)
    end)
end
 
function Fire:removeFire(fire, extinguished)
    --if fire is still functional
    if fire:getParent() then
        --remove fire
        fire:removeFromParent()
 
        --release coordinates from taken
        self.coords[fire.ind] = false
        fire.ind = nil
 
        --put fire to pool for reusing
        table.insert(self.pool, fire)
 
        --dispatch an event
        local event = Event.new("fire")
        event.extinguished = extinguished
        self:dispatchEvent(event)
    end
end
 
function Fire:onEnterFrame()
    if self.counter == self.spawnRate then
        self.counter = 0
        self:spawn()
    else
        self.counter = self.counter + 1
    end
end
 
--remove enter frame event when changing scene, etc
function Fire:onRemoved()
    self:removeEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
end

And usage would be something like this:

local fire = Fire.new()
stage:addChild(fire)
fire:addEventListener("fire", function(e)
    if e.extinguished then
        --user extinguished it, add a score
   else
      -- user did not extinguish it, remove a life
   end
end)

Did not test the code, wrote from the top of my head, hope that helps

iWatts · June 2014

Awesome, Ill implement this, and then tell you if it works

iWatts · June 2014

Just wondering, is there an "easy" or "easier" way to do this? I could just copy/ paste but then I wouldn't learn anything. I can do basic stuff, but a lot of that language seems completely new. Is there a way to use a simple timer to tell it when to add or take away a flame?

If you could help me get this working in simple, N00b terms and code it would be awesome, if its a more complicated problem, and I should learn a bit more before trying it, thats cool to.
thanks!

iWatts · June 2014

Heres a copy of the main, so you can look through it to see the kind of programmer i am, and if its possible to complete this problem using knowledge that I have demonstrated

ar2rsawseen · June 2014

@iWatts sure, I see, can't tell that your solution is efficient nor elegant, but you are right, in order to learn, you would need to make a lot of mistakes.

So what is your exact current problem?

You have a table of flames and you can spawn new fires like this for example

function spawnFlame()
    local available = {}
    --this way we ignore and use only flames that are not yet visible
    for i = 1, #flames do
        if not flames[i]:isVisible() then
            table.insert(available, i)
        end
    end
    local ind = available[math.random(#available)]
    flames[ind]:setVisible(true)
    Timer.delayedCall(4000, function()
        flames[ind]:setVisible(false)
        --deduct life here
    end)
end

iWatts · June 2014

Thanks for the help dude! Its awesome to see advanced programers help out the noobs haha. i added in what you showed me, and the program runs but fires arent added. So just so were on the same track heres the idea:
there are 9 windows, and I have it start of by spawning 3 fires in 3 random windows (the fires are a .mov so they are moving. Ideally, fires would randomly spawn to random windows, and each fire stays for 3 seconds and then dissapears. if it dissapears, I loose a point (for not putting it out) if i shoot it with the hose, i gain a point. If you have any questions regarding my logic, feel free to ask. Lets tackle this problem!
Thanks, iWatts

iWatts · June 2014

also, keep in mind I have an array set up at the beginning that creates flames[i] from 1 to 16, each flame holds a position in the window (flame[1] is top left, flame[2] is top middle, ect..)

ar2rsawseen · June 2014

yep that is just a function, you also need to call it periodically, the best way is to do something like this:

local counter = 0
local spawnRate = 100 --change spawn rate to what you need
stage:addEventListener(Event.ENTER_FRAME, function()
    if counter == spawnRate then
        counter = 0
        spawnFlame()
    else
        counter = counter + 1
    end
end)

iWatts · June 2014

were getting there. I run the program, and then a few seconds later the program closes with this problem

ar2rsawseen · June 2014

yep fixed the type from : to .

iWatts · June 2014

sweet. IT WORKED! Thanks so much for the help! I have a few last questions.
1. i have a text that says you put out blank / blank fires. where would I add one to each side of that? and second how do i change how quickly they spawn, and despawn/ thanks again!

ar2rsawseen · June 2014

2) to increase/decrease fire rate increase/decrease value of spawnRate variable
How quickly they disappear depends on the number in Timer.delayedCall(4000, which is 4000ms or 4 seconds
1) I did not really understood your question

Mells · June 2014

@ar2rsawseen I like your attitude and willingness to help/teach.

ar2rsawseen · June 2014

@Mells I don't mind while it does not burn me out completely

iWatts · June 2014

Thanks so much for your help dude! I actually figured out the first question, and thanks for reminding me of the second. Your a true lad.

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