Game speed increases itself on every restart - Corona - lua

Question

am trying to make a jetpack joyride concept game on corona. First of all unlike other sdk where when you change a scene, the previous scene is automatically removed, in corona you have to remove each and object and function yourself.
After a week I was finally able to remove objects while changing scene, but now I have ran into a new problem. Everytime when I change scenes and come back to the gameScreen the speed of lasers and missiles increases every time ( maybe twice? ). How can I reset its speed?
I even added another "gameStatus" variable to remove the event listener and tried to print it, but game status never actually returned "ended", it was always "running". Here is the gameScene screen where everything happens
EDIT : I just noticed something, For example if 3 objects have already spawned then after reloading the screen only first 3 objects seem to be fast and its normal from fourth.
local composer = require( "composer" )
local scene = composer.newScene()
local physics = require( "physics" )
physics.start()
local image, text1
local function onSceneTouch( self, event )
if event.phase == "began" then
composer.gotoScene( "startScreen", "fade", 400 )
return true
end
end
function scene:create( event )
local sceneGroup = self.view
-- Variable
---------------------------------------
sW = display.contentWidth
sH = display.contentHeight
-- trying to reset gameStatus on restart
gameStatus = "ended"
gameStatus = "running"
--------------------------------------------------------
backgroundTiles = {}
drawBackground = function()
cieling = display.newRect( 0, 0, 2 * sW, sH * 0.05)
physics.addBody( cieling, "static", { density=0, friction=0, bounce=0 } )
cieling.x, cieling.y = cieling.contentWidth / 4, cieling.contentHeight * 0.25
cieling.alpha = 0
cieling.name = "ceiling"
ground = display.newRect( 0, sH, 2 * sW, sH * 0.05)
physics.addBody( ground, "static", { density=3, friction=1, bounce=0.1 } )
ground.x, ground.y = ground.contentWidth / 4, sH - ground.contentHeight * 0.25
ground.alpha = 0
ground.name = "ground"
end
drawBackground()
--------------------------------------------------------
--------------------------------------------------------
drawBird = function()
bird = display.newImageRect( "a/img/hero/hero.png", 80, 58)
bird.x, bird.y = 0 - sW * 0.1, ground.y - ground.contentHeight - 10
bird.isFixedRotation = true; bird.angularVelocity = 0;
physics.addBody( bird, { density=1, friction=0.5, bounce=0.1 } )
bird.name = "bird"
sceneGroup:insert( bird )
bird:addEventListener( "collision", onCollision )
end
coinsCollected, tokensCollected = 0, 0
birdFlight = function()
if ( gameStatus == "running" ) then
transition.to(bird, {
y = bird.y - 75,
transition = easing.outQuad,
onComplete = function() end
})
function birdFlight()
--transition.to( bird, { rotation=-45, time=300 } )
end
birdFlight()
function birdFall()
--transition.to( bird, { rotation=90, time=300 } )
end
timer.performWithDelay(700, birdFall, 1)
end
end
display.currentStage:addEventListener( "tap", birdFlight )
function onCollision(event)
if event.phase == "began" then
if event.other.name == "coin" then
coinsCollected = coinsCollected + 1
end
if event.other.name == "token" then
tokensCollected = tokensCollected + 1
end
if event.other.name == "missile" or event.other.name == "laser" or event.other.name == "rod" then
-- game ended
end
end
end
drawBird()
function atFrame(event)
if gameStatus == "running" then
bird.x,bird.y = sW / 3,bird.y + 9
if ( bird.y > sH - 70) then bird.y = sH - 70 end
if ( gameStatus == "ended" ) then bird.y = bird.y + 15 end
end
end
Runtime:addEventListener( "enterFrame", atFrame )
--------------------------------------------------------
--------------------------------------------------------
missile, missileAlert, missileMoving = {}, {}, {}
function removeMissile(i)
local onEnterFrame = function( event )
if missile[i] ~= nil and missile[i].x ~= nil and gameStatus == "running" then
if missile[i].x < -100 then
display.remove( missile[i] )
missile[i] = nil
end
end
end
Runtime:addEventListener( "enterFrame", onEnterFrame )
print(gameStatus)
if gameStatus == "ended" then
Runtime:removeEventListener( "enterFrame", onEnterFrame )
end
end
function flyMissile(i)
local onEnterFrame = function( event )
if missile[i] ~= nil and missile[i].x ~= nil and missile[i].y ~= nil and gameStatus == "running" then
if missileMoving[i] == true then
missile[i].y = bird.y
end
missile[i].x = missile[i].x - 5
if missileAlert[i] ~= nil then
if missileMoving[i] == true then
missileAlert[i].y = bird.y
end
if missile[i].x < sW then
display.remove( missileAlert[i] )
missileAlert[i] = nil
end
end
end
end
Runtime:addEventListener( "enterFrame", onEnterFrame )
print(gameStatus)
if gameStatus == "ended" then
Runtime:removeEventListener( "enterFrame", onEnterFrame )
end
end
function holdMissile(i)
local onEnterFrame = function( event )
if missile[i] ~= nil and missile[i].x ~= nil and gameStatus == "running" then
if missile[i].x < sW * 1.5 then
if missileAlert[i] ~= nil then
missileAlert[i]:setFillColor(1,1,0)
end
missileMoving[i] = false
end
end
end
Runtime:addEventListener( "enterFrame", onEnterFrame )
print(gameStatus)
if gameStatus == "ended" then
Runtime:removeEventListener( "enterFrame", onEnterFrame )
end
end
function spawnMissile(i)
missile[i] = display.newRect( sW*2, sH/2, 80, 80 )
missileAlert[i] = display.newRect( sW-80, bird.y, 80, 80 )
physics.addBody(missile[i],"kinematic",{isSensor=true})
missile[i].name = "missile"
sceneGroup:insert( missile[i] )
sceneGroup:insert( missileAlert[i] )
missileMoving[i] = true
flyMissile(i)
removeMissile(i)
holdMissile(i)
end
spawnMissile(1)
--------------------------------------------------------
--------------------------------------------------------
laser = {}
function moveAndRemovelaser(i)
local onEnterFrame = function( event )
if laser[i] ~= nil and laser[i].x ~= nil and gameStatus == "running" then
laser[i].x = laser[i].x - 5
if laser[i].x < 0 - sW / 2 then
display.remove( laser[i] )
laser[i] = nil
end
end
end
Runtime:addEventListener( "enterFrame", onEnterFrame )
print(gameStatus)
if gameStatus == "ended" then
Runtime:removeEventListener( "enterFrame", onEnterFrame )
end
end
function spawnlaser(i)
laserSize = math.random(1,2)
laserPosition = math.random(1,3)
laserRotation = math.random(1,4)
if laserSize == 1 then
laser[i] = display.newRect( 100,100,50,sH/3 )
else
laser[i] = display.newRect( 100,100,50,sH/2 )
end
sceneGroup:insert( laser[i] )
laser[i].x = sW * 2
laser[i].y = sH / 2
laser[i].name = "laser"
if laserPosition == 1 and laserRotation ~= 4 then
laser[i].y = sH * 0.05 + 12
laser[i].anchorY = 0
elseif laserPosition == 3 and laserRotation ~= 4 then
laser[i].y = sH * 0.95 - 12
laser[i].anchorY = 1
end
if laserPosition == 1 and laserRotation == 4 then
laser[i].y = sH * 0.05 + laser[i].contentHeight / 2
elseif laserPosition == 3 and laserRotation == 4 then
laser[i].y = sH * 0.95 - laser[i].contentHeight / 2
end
if laserRotation == 1 then
laser[i].rotation = -45
elseif laserRotation == 2 then
laser[i].rotation = 0
elseif laserRotation == 3 then
laser[i].rotation = 45
elseif laserRotation == 4 then
local onEnterFrame = function( event )
if laser[i] ~= nil and laser[i].rotation ~= nil then
laser[i].rotation = laser[i].rotation + 5
end
end
Runtime:addEventListener( "enterFrame", onEnterFrame )
end
laser[i]:setFillColor(1,1,0)
physics.addBody(laser[i],"kinematic",{isSensor=true})
moveAndRemovelaser(i)
end
spawnlaser(1)
--------------------------------------------------------
image = display.newRect (100,100,100,100)
image.x = display.contentCenterX
image.y = display.contentCenterY
sceneGroup:insert( image )
image.touch = onSceneTouch
text1 = display.newText( "Game Screen", 0, 0, native.systemFontBold, 24 )
text1:setFillColor( 255 )
text1.x, text1.y = display.contentWidth * 0.5, 50
sceneGroup:insert( text1 )
end
function scene:show( event )
local phase = event.phase
if "will" == phase then
gameStatus = "ended"
end
if "did" == phase then
print( "4" )
composer.removeScene( "startScreen" )
image:addEventListener( "touch", image )
gameStatus = "running"
end
end
function scene:hide( event )
local phase = event.phase
if "will" == phase then
print( "5" )
gameStatus = "ended"
image:removeEventListener( "touch", image )
Runtime:removeEventListener( "enterFrame", onEnterFrame )
end
end
function scene:destroy( event )
print( "6" )
end
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
return scene

Answer 1

You are getting this problem because you are registering an event listener twice.
You need to add and remove them only when the scene enters and exits. The proper place to remove game objects is scene:destroy() and scene:hide()
My advice is that you try to re-organize your code and try to follow these guidelines:
scene:create() : This happens the first time a scene is used. You want create your game objects here. This event will only happen once, unless the scene is destroyed and then used again.
scene:show() : You want to register all your event listeners here (touch, etc) and setup your game. This function gets called every-time the scene is shown. Every event listener that is registered here should be un-registered to prevent double-triggering.
scene:hide() : You want to un-register all event listeners here. This will prevent the next scene from triggering events on your previous scene's listeners too.
scene:destroy() : You want to remove all game objects here (images, text, widgets, etc). The scene is no longer needed and everything should be cleaned.
To better understand how the Scene's work I recommend reading this doc:
http://coronalabs.com/blog/2014/01/21/introducing-the-composer-api-plus-tutorial/

Answer 2

So I ended up creating a function and putting all the removeEventListeners in that function and called that function when the game ended.
For future reference always keep a list of all the timer and event listeners that you have created anywhere in the screen and remove them all together when ending the game