Spawn Function in Corona SDK

Question

Okay so I kind of am almost there but need a little push:

My dustbins spawn but there are a few to begin with like I want and then after about 30 seconds of the numbers of dustbins increasing there are 1000's all clumped together.. What can i do to alter my function so that its only ever a few at a time:

function spawnDustbin()
dustbin = {}
for i = 1,800 do
    dustbin[i] = display.newImage("dustbin.png")
    dustbin[i].xScale = 0.55
    dustbin[i].yScale = 0.55
    dustbin[i].y = 555
    dustbin[i].x = (math.random(1000,1500) * i)
    dustbin[i].speed = 4
    physics.addBody( dustbin[i], "static", { friction=1.0, density=1.0, bounce=0, radius=30,} )
    dustbin[i].enterFrame = moveDustbin
    Runtime:addEventListener("enterFrame", dustbin[i])
    end
end

and the movedustbin function simply moves the dustbin in the negative x direction:

   function moveDustbin(self,event)
    if self.x < -2560 then
    self.x = 2560
    else
                self.x = self.x - val
            end
        end

First 20ish seconds: http://i.stack.imgur.com/7iEeP.png

After 20 seconds: http://i.stack.imgur.com/aae0D.png

Thank you very much James

James Mallon James Mallon · Accepted Answer · 2014-02-24T16:14:02

That "spawnDustbin" function above is spawning 800 dustbins every frame. That will really crush your performance, and I am pretty certain you don't want to create that many objects every frame.

You might want to do something like this:

local dustbin = {}
local i = 0
local function spawnDustbin()
    i = i+1
    dustbin[i] = display.newImage("dustbin.png")
    dustbin[i].xScale = 0.55
    dustbin[i].yScale = 0.55
    dustbin[i].y = 555
    dustbin[i].x = (math.random(1000,1500) * i)
    dustbin[i].speed = 4
    physics.addBody( dustbin[i], "static", { friction=1.0, density=1.0, bounce=0, radius=30,} )
    dustbin[i].enterFrame = moveDustbin
    Runtime:addEventListener("enterFrame", dustbin[i])
end

timer.performWithDelay(500, spawnDustbin, 10)

YMMV but that will spawn 10 dustbins in 5 seconds.

Spawn Function in Corona SDK

1 Answers