Spawn Function in Corona SDK - function

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

Answer 1

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.