A horizontal scrolling Corona game using basic physics.
Developed by: Shawn Grimes for APPlied Club
Artwork provided by Vicki Wenderlich
- Run ScalingSample project
- Open config.lua, change scale="letterBox"
- Demo difference on each device
-
Open CloudJumper base
-
The code in the CloudJumper base scrolls random clouds across the background.
-
Open Physics Editor
-
Drag in Cloud1,2,3 and char_walk_2
-
Create physics objects See this Corona Physics Editor Tutorial for more information on using Physics Editor
-
Add physics library to CloudJumper base
-- init physics local physics = require("physics") physics.start() -
Now add our exported physics file from Physics Editor
local physicsData = (require "CloudPhysics").physicsData(1.0) -
Add score label
------Create Clouds to walk on --create display group for walking clouds local walkingCloudDisplayGroup=display.newGroup() local walkingCloudSpeed=.05 --Create a label to count how many clouds have passed local scoreCount=0 local scoreLabel=display.newText("Score: 0", 10,40, native.systemFontBold , 48) scoreLabel:setTextColor(255, 255, 255) walkingCloudDisplayGroup:insert(scoreLabel) -
Run the app in the simulator, you should see the new score label added to the scene.
-
Create initial platforms
--Create function to remove clouds when they travel off the scene
local function removeWalkingCloud(cloudToRemove)
scoreCount=scoreCount+1
scoreLabel.text="Score: "..scoreCount
cloudToRemove:removeSelf()
cloudToRemove=nil
end
--Create variables to track the location of the last cloud
local lastX=0
local lastY=display.contentWidth/2
local function createStartingWalkingClouds()
for i=1,5 do
local walkingCloud=display.newImage("cloud2.png")
physics.addBody(walkingCloud,physicsData:get("cloud2"))
walkingCloud.bodyType="static"
walkingCloud.x=lastX+walkingCloud.contentWidth/2
lastX=lastX+walkingCloud.contentWidth
walkingCloud.y=lastY
local walkingCloudDistance=- walkingCloud.x - walkingCloud.contentWidth/2
local walkingCloudTravelSpeed= math.abs(walkingCloudDistance/walkingCloudSpeed)
walkingCloud.transition=transition.to(walkingCloud,{time=walkingCloudTravelSpeed, x=-walkingCloud.x-walkingCloud.contentWidth/2, onComplete=removeWalkingCloud})
walkingCloudDisplayGroup:insert(walkingCloud)
end
end
createStartingWalkingClouds()
- Run the app in the simulator, you should see the foreground clouds.
- Add our hero
--Create hero object
--include movieclip object
local movieClip=require("movieclip")
local heroAngel=movieClip.newAnim({"char_jump_1.png","char_jump_2.png","char_shoot_1.png","char_shoot_2.png","char_walk_1.png","char_walk_2.png"})
heroAngel.x=heroAngel.contentWidth
heroAngel.y=50
heroAngel:setSpeed(0.4)
heroAngel:play({startFrame=1,endFrame=2,loop=0,remove=false})
physics.addBody(heroAngel,physicsData:get("char_walk_2"))
````
11. Run the app in the simulator, you should see the hero character fall from the sky and land on the foreground clouds. Then he falls over :(
11. Fix the hero so he's upright and doesn't fall over. We are going to attach him to a rectangle object below with a pivot joint. Pivot joints can only move up and down and this will prevent the hero angel from rotating.
--This physics joint keeps our angel upright
local rect = display.newRect( 50, 50, 100, 100 )
rect:setFillColor( 255, 255, 255, 100 )
rect.isVisible = true -- optional
rect.y=display.contentHeight
physics.addBody( rect, "static",{ isSensor = true } )
local pistonJoint=physics.newJoint("piston",heroAngel, rect,heroAngel.x,heroAngel.y,0,-100)
12. Now set the rect.isVisible = false to hide it on the scene.
12. Let's make the hero jump when we touch the screen
--Function to make the angel jump when the screen is tapped
local function jumpAngel(event)
heroAngel:applyLinearImpulse( 0, -225, heroAngel.x, heroAngel.y )
end
Runtime:addEventListener("tap", jumpAngel)
13. Let's add a better jump function to make sure you can't infinite jump with collision detection:
--Function to make the angel jump when the screen is tapped
local isJumping=false
local function jumpAngel(event)
if(isJumping ~= true) then
--Change to flying frames
heroAngel:play({startFrame=1,endFrame=2,loop=0,remove=false})
isJumping=true
heroAngel:applyLinearImpulse( 0, -200, heroAngel.x, heroAngel.y )
end
end
Runtime:addEventListener("tap", jumpAngel)
--Reset the angel when he lands
local function onLocalCollision(self, event)
if ( event.phase == "began" ) then
isJumping=false
--Change back to walking frames
heroAngel:play({startFrame=5,endFrame=6,loop=0,remove=false})
end
end
heroAngel.collision = onLocalCollision
heroAngel:addEventListener( "collision", heroAngel )
14. Adjust gravity if tap is held
--Function to adjust gravity if touching and flying local function adjustGravityForTouch(event) if ( event.phase=="began" ) then print("changing gravity") physics.setGravity( 0, 2.4 ) elseif(event.phase=="ended") then print("gravity normal") physics.setGravity( 0, 9.8 ) end end Runtime:addEventListener("touch", adjustGravityForTouch)
Adding Polish
------
1. Open CloudJumper-NeedsPolish
2. Run and show current state of game
3. Introduce [Corona Director Class](http://developer.anscamobile.com/code/director-class-10)
4. Rename main.lua to GameScene.lua
5. Create new main.lua
6. Copy code to main.lua
-------------------------------------------------------------------------------------
--
-- main.lua
--
-- Your code here
-- IMPORT DIRECTOR CLASS
local director = require("director")
-- CREATE A MAIN GROUP
local mainGroup = display.newGroup()
-- MAIN FUNCTION
local main = function ()
-- Add the group from director class
mainGroup:insert(director.directorView)
director:changeScene("MainMenuScene")
-- Return true to signal that the function was successful
return true
end
main()
7. Create MainMenuScene.lua
8. Copy template.lua code into MainMenuScene.lua
9. Create background image in MainMenuScene.lua
local mainMenuBackground=display.newImage("Cloud_Jumper_TitleScreen.png")
localGroup:insert(mainMenuBackground)
10. Run the app, you should see the MainMenu Scene now.
10. Add a play button:
local ui = require("ui")
local playButtonPressed = function (event )
if event.phase == "release" then
director:changeScene( "GameScene", "overFromRight" )
end
end
local playButton = ui.newButton{
default = "button_play_up.png",
over = "button_play_down.png",
onEvent = playButtonPressed,
id = "btn001",
text = "",
font = "Trebuchet-BoldItalic",
textColor = { 51, 51, 51, 255 },
size = 22,
emboss = true
}
playButton:setReferencePoint(display.CenterReferencePoint)
playButton.x=display.contentWidth/2
playButton.y=display.contentHeight-display.contentHeight/5
--Add start button to local group
localGroup:insert(playButton)
11. Now open GameScene.lua
12. At the top add:
module(..., package.seeall)
new = function ()
13. At the bottom add:
return localGroup
end
14. Run the game. You should be able to launch the gameplay scene now.
14. Restarting the game
15. Let's add a restart button to our game over logic. Line 215, add:
--Show restart button
local ui=require("ui")
local restartButtonPressed = function (event )
if event.phase == "release" then
--Clean up the scene before we start it again
cleanUpScene()
director:changeScene( "GameScene", "overFromRight" )
end
end
--Create a restart Button
local restartButton = ui.newButton{
default = "button_restart_up.png",
over = "button_restart_down.png",
onEvent = restartButtonPressed,
id = "btn001",
text = "",
font = "Trebuchet-BoldItalic",
textColor = { 51, 51, 51, 255 },
size = 22,
emboss = true
}
restartButton:setReferencePoint(display.CenterReferencePoint)
restartButton.x=display.contentWidth/2
restartButton.y=restartButton.y + restartButton.contentHeight
localGroup:insert(restartButton)
16. How about some background music?
17. Open main.lua and add the following around line 17 (after `local main = function ()` ):
--Play background music
local backgroundMusicObject = audio.loadStream("backgroundMusic.mp3")
audio.play(backgroundMusicObject)
18. Run the game now