Create a brick breaker game with the corona SDK: Collision Detection

Original article, reprinted Please note:Reprinted from All-iPad.netLink:Create a brick breaker game with the corona SDK: Collision Detection

This is the second part of the series of tutorials. Click the link on the next page for the complete content:

• Create a brick breaker game with the corona SDK: Application setup
• Create a brick breaker game with the corona SDK: game controls
• Create a brick breaker game with the corona SDK: Collision Detection

 

Step 35: Detect brick collisions

When the ball hits the brick, we will use the same method as the ball board collision to check which side is running. The Code is as follows:

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functionremoveBrick(e)-- Check the which side of the brick the ball hits, left, rightif(e.other.name == 'brick'and (ball.x + ball.width * 0.5) < (e.other.x + e.other.width * 0.5)) thenxSpeed = -5elseif(e.other.name == 'brick'and (ball.x + ball.width * 0.5) >= (e.other.x + e.other.width * 0.5)) thenxSpeed = 5endend

 

 

Step 37: Remove brick

When the ball hits the brick, the brick disappears.

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-- Bounce, Removeif(e.other.name == 'brick') thenySpeed = ySpeed * -1e.other:removeSelf()e.other = nilbricks.numChildren = bricks.numChildren - 1

 

 

Step 38: Add score

Each time you encounter a brick, you get 100 points.

318	score = score + 1scoreNum.text = score * SCORE_CONSTscoreNum:setReferencePoint(display.CenterLeftReferencePoint)scoreNum.x = 54end

 

Step 39: Check bricks

When all bricks are eliminated, the player wins

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if(bricks.numChildren < 0) thenalert('  You Win!', '  Next Level ›')gameEvent = 'win'endend

 

 

Step 40: ball movement

The movement of the ball is controlled by the xspeed and yspeed variables. When the UPDATE function is executed, the ball starts to move.

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functionupdate(e)-- Ball Movementball.x = ball.x + xSpeedball.y = ball.y + ySpeed

 

 

Step 41: Wall collision

The following code checks the collision between the ball and the wall, and returns a reverse direction to the ball when a collision occurs.

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if(ball.x < 0) then ball.x = ball.x + 3 xSpeed = -xSpeed end--Leftif((ball.x + ball.width) > display.contentWidth) then ball.x = ball.x - 3 xSpeed = -xSpeed end--Rightif(ball.y < 0) then ySpeed = -ySpeed end--Up

 

 

Step 42: loss condition

344	if(ball.y + ball.height > paddle.y + paddle.height) then alert('  You Lose', '  Play Again ›') gameEvent = 'lose'end--down/lose

 

 

Step 43: Game status message

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functionalert(t, m)gameListeners('remove')alertBg = display.newImage('alertBg.png')box = display.newImage('alertBox.png', 90, 202)transition.from(box, {time = 300, xScale = 0.5, yScale = 0.5, transition = easing.outExpo})titleTF = display.newText(t, 0, 0, 'akashi', 19)titleTF:setTextColor(254,203,50)titleTF:setReferencePoint(display.CenterReferencePoint)titleTF.x = display.contentCenterXtitleTF.y = display.contentCenterY - 15msgTF = display.newText(m, 0, 0, 'akashi', 12)msgTF:setTextColor(254,203,50)msgTF:setReferencePoint(display.CenterReferencePoint)msgTF.x = display.contentCenterXmsgTF.y = display.contentCenterY + 15box:addEventListener('tap', restart)alertScreen = display.newGroup()alertScreen:insert(alertBg)alertScreen:insert(box)alertScreen:insert(titleTF)alertScreen:insert(msgTF)end

 

 

Step 44: restart

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functionrestart(e)if(gameEvent == 'win'and table.maxn(levels) > currentLevel) thencurrentLevel = currentLevel + 1changeLevel(levels[currentLevel])--next levellevelNum.text = tostring(currentLevel)elseif(gameEvent == 'win'and table.maxn(levels) <= currentLevel) thenbox:removeEventListener('tap', restart)alertScreen:removeSelf()alertScreen = nilalert('  Game Over', '  Congratulations!')gameEvent = 'finished'elseif(gameEvent == 'lose') thenchangeLevel(levels[currentLevel])--same levelelseif(gameEvent == 'finished') thenaddMenuScreen()transition.from(menuScreen, {time = 300, y = -menuScreen.height, transition = easing.outExpo})box:removeEventListener('tap', restart)alertScreen:removeSelf()alertScreen = nilcurrentLevel =scoreText:removeSelf()scoreText = nilscoreNum:removeSelf()scoreNum = nillevelText:removeSelf()levelText = nillevelNum:removeSelf()levelNum = nilball:removeSelf()ball = nilpaddle:removeSelf()paddle = nilscore = 0endend

 

 

Step 45: Change level

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functionchangeLevel(level)-- Clear Level Bricksbricks:removeSelf()bricks.numChildren = 0bricks = display.newGroup()-- Remove Alertbox:removeEventListener('tap', restart)alertScreen:removeSelf()alertScreen = nil-- Reset Ball and Paddle positionball.x = (display.contentWidth * 0.5) - (ball.width * 0.5)ball.y = (paddle.y - paddle.height) - (ball.height * 0.5) -2paddle.x = display.contentWidth * 0.5-- Redraw BricksbuildLevel(level)-- Startbackground:addEventListener('tap', startGame)end

 

 

Step 46: Call Main Function

Call the main () function to start the program.

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Main()

 

 

Step 47: Create the loading screen

Default.png is added to the project directory, and corona compiler automatically adds it as loading screen

 

Step 48: icon

Note that different platforms require different icon sizes

 

 

Step 49: Testing in the simulator

Use the corona simulator to open the project directory for testing.

 

Step 50: Build

Select build from the File menu of Corona simulator to start compilation.

 

Address: http://mobile.tutsplus.com/tutorials/corona/create-a-brick-breaker-game-with-the-corona-sdk-collision-detection/

 

 

 

Original article, reprinted Please note:Reprinted from All-iPad.net

Link:Create a brick breaker game with the corona SDK: Collision Detection