This is the second installment in our Corona SDK Bubble Popping game tutorial. In today's tutorial, we'll add to our interface by coding the game interaction. Read on!
Also available in this series:
- Create a Bubble Popping Game - Interface Creation
- Create a Bubble Popping Game - Adding Interaction
Where We Left Off. . .
Please be sure to check part 1 of the series to fully understand and prepare for this tutorial.
Step 1: Start Button Listeners
This function adds the necesary listeners to the TitleView buttons.
function startButtonListeners(action)
if(action == 'add') then
playBtn:addEventListener('tap', showGameView)
creditsBtn:addEventListener('tap', showCredits)
else
playBtn:removeEventListener('tap', showGameView)
creditsBtn:removeEventListener('tap', showCredits)
end
end
Step 2: Show Credits
The credits screen is shown when the user taps the about button, a tap listener is added to the credits view to remove it.
function showCredits:tap(e)
playBtn.isVisible = false
creditsBtn.isVisible = false
creditsView = display.newImage('credits.png', 0, display.contentHeight)
lastY = titleBg.y
transition.to(titleBg, {time = 300, y = (display.contentHeight * 0.5) - (titleBg.height + 30)})
transition.to(creditsView, {time = 300, y = (display.contentHeight * 0.5) + 35, onComplete = function() creditsView:addEventListener('tap', hideCredits) end})
end
Step 3: Hide Credits
When the credits screen is tapped, it'll be tweened out of the stage and removed.
function hideCredits:tap(e)
transition.to(creditsView, {time = 300, y = display.contentHeight + 25, onComplete = function() creditsBtn.isVisible = true playBtn.isVisible = true creditsView:removeEventListener('tap', hideCredits) display.remove(creditsView) creditsView = nil end})
transition.to(titleBg, {time = 300, y = lastY});
end
Step 4: Show Game View
When the Start button is tapped, the title view is tweened and removed revealing the game view. There are many parts involved in this view so we'll split them in the next steps.
function showGameView:tap(e)
transition.to(titleView, {time = 300, x = -titleView.height, onComplete = function() startButtonListeners('rmv') display.remove(titleView) titleView = nil end})
Step 5: Walls
Next we add the walls to the stage. They are created using the drawing API.
-- Walls left = display.newLine(0, 240, 0, 720) right = display.newLine(320, 240, 320, 720) top = display.newLine(160, 0, 480, 0) bottom = display.newLine(160, 480, 480, 480)
Step 6: Bubbles
This part creates five bubbles in the screen at a random position.
bubbles = display.newGroup()
for i = 1, 5 do
local rx = 21 + math.floor(math.random() * (display.contentWidth - 42))
local ry = 21 + math.floor(math.random() * (display.contentHeight - 42))
local b = display.newImage('bubble.png', rx, ry)
b.name = 'bubble'
Step 7: Bubble Physics
Here we add physics to our new bubble.
-- Bubble Physics
physics.addBody(b, 'dynamic', {radius = 21, bounce = 1})
b:setLinearVelocity(100, 100)
bubbles:insert(b)
end
Step 8: Wall Physics
And do the same with our walls.
-- Walls Physics physics.addBody(left, 'static') physics.addBody(right, 'static') physics.addBody(top, 'static') physics.addBody(bottom, 'static')
Step 9: TextFields
Now we add the level, popped and required bubbles textfields.
-- Level TextField
level = display.newImage('level.png', 2, 0)
levelN = display.newText('1', 54, 5, native.systemFont, 15)
levelN:setTextColor(255, 255, 255)
-- Popped TextField
popped = display.newImage('popped.png', 126, 0)
poppedN = display.newText('0', 187, 5, native.systemFont, 15)
poppedN:setTextColor(255, 255, 255)
-- Required TextField
required = display.newImage('required.png', 231, 0)
requiredN = display.newText('4', 306, 5, native.systemFont, 15)
requiredN:setTextColor(255, 255, 255)
bullets = display.newGroup()
end
Step 10: Game Listeners
This function adds the necessary listeners to start the game logic.
function gameListeners(action)
if(action == 'add') then
bg:addEventListener('tap', createBullets)
else
bg:removeEventListener('tap', createBullets)
Runtime:removeEventListener('enterFrame', update)
end
end
Step 11: Create Bullets
This code runs when the background is tapped.
First we create the bullet graphics.
function createBullets(e)
for i = 1, 4 do
local bullet = display.newImage('bullet.png', e.x, e.y)
Step 12: Set Direction
Then we give it a direction by setting the linear velocity.
-- Set direction
if(i == 1) then bullet.x = bullet.x - 8 physics.addBody(bullet, 'kinematic', {radius = 7}) bullet:setLinearVelocity(-150, 0) end --left
if(i == 2) then bullet.x = bullet.x + 8 physics.addBody(bullet, 'kinematic', {radius = 7}) bullet:setLinearVelocity(150, 0) end --right
if(i == 3) then bullet.y = bullet.y - 8 physics.addBody(bullet, 'kinematic', {radius = 7}) bullet:setLinearVelocity(0, -150) end --up
if(i == 4) then bullet.y = bullet.y + 8 physics.addBody(bullet, 'kinematic', {radius = 7}) bullet:setLinearVelocity(0, 150) end --down
bullet:addEventListener('collision', onCollision)
bullets:insert(bullet)
bg:removeEventListener('tap', createBullets)
end
Runtime:addEventListener('enterFrame', update)
end
Step 13: Collisions
The collisions are handled by the next function. A sound is played, the score increases and removes the bubble of the screen.
function onCollision(e) if(e.other.name == 'bubble') then audio.play(pop) display.remove(e.other) poppedN.text = tostring(tonumber(poppedN.text) + 1) end end
Step 14: Remove Offstage Bullets
This code will remove any bullet that is out of sight.
function update(e) -- Check for offstage bullets for i = 1, bullets.numChildren do if(bullets[i] ~= nil) then if(bullets[i].x < 0 or bullets[i].x > 320 or bullets[i].y < 0 or bullets[i].y > 480) then display.remove(bullets[i]) end end end
Step 15: Level Complete
Here we check if the popped bubbles have reached the required quantity and call a win alert if true.
-- Check if required bubbles were popped
if(bullets.numChildren == 0 and tonumber(poppedN.text) >= tonumber(requiredN.text)) then
alert('win')
elseif(bullets.numChildren == 0 and tonumber(poppedN.text) < tonumber(requiredN.text)) then
alert('lose')
end
end
Step 16: Alert
The alert function displays a message according to the type of alert called (level complete or failed).
function alert(action)
gameListeners('rmv')
if(action == 'win') then
local alertView = display.newImage('won.png', 80, display.contentHeight * 0.5 - 41)
transition.from(alertView, {time = 300, y = -82, delay = 500})
else
local alertView = display.newImage('lost.png', 80, display.contentHeight * 0.5 - 41)
transition.from(alertView, {time = 300, y = -82, delay = 500})
end
end
Step 17: Call Main Function
In order to start the game, the Main function needs to be called. With the above code in place, we'll do that here:
Main()
Step 18: Loading Screen
The Default.png file is an image that will be displayed right when you start the application while the iOS loads the basic data to show the Main Screen. Add this image to your project source folder, it will be automatically added by the Corona compliler.
Step 19: Icon
Using the graphics you created before you can now create a nice and good looking icon. The icon size for the non-retina iPhone icon is 57x57px, but the retina version is 114x114px and the iTunes store requires a 512x512px version. I suggest creating the 512x512 version first and then scaling down for the other sizes.
It doesn't need to have the rounded corners or the transparent glare, iTunes and the iPhone will do that for you.
Step 20: Testing in Simulator
It's time to do the final test. Open the Corona Simulator, browse to your project folder, and then click open. If everything works as expected, you are ready for the final step!
Step 21: Build
In the Corona Simulator go to File > Build and select your target device. Fill the required data and click build. Wait a few seconds and your app will be ready for device testing and/or submission for distribution!
Conclusion
Experiment with the final result and try to make your custom version of the game!
I hope you liked this tutorial series and find it helpful. Thank you for reading!
