Random levels

[sondre.lovhaug]

Hi! I am making a puzzle game and I need the levels to be randomized for each device.

Each level is basically a collection of images all having one word in common, like 4 pics one word. But I need a way to make them appear in random order, so that each player will have a different experience.

My hierarchy is like this:
root
 - Levels
       - 1
             -1.jpg

             -2.jpg

             -3.jpg

             -4.jpg

       - 2

             -1.jpg

             -2.jpg

             -3.jpg

             -4.jpg

What I had in mind was to have one array to hold all the levels the player has completed, and for each time he goes to a new level,  loop through all the levels to check for unfinished ones by comparing them to the array. With all the unfinished levels in an array I could use a math.random function to choose a level from that array. 

However, Is there a way I could make Corona loop through all the levels in the FOLDER, and check them up against the array containing the finished levels. If this is possible it would make adding more levels later on much easier.

Thanks!
 

[AlanPlantPot]

I have a function to check the contents of the folder:

function fileExists(theFile) local filePath = system.pathForFile(theFile, system.TemporaryDirectory) local results = false if filePath == nil then return false else local file = io.open(filePath, "r") --If the file exists, return true if file then io.close(file) results = true end return results end end

but to be honest, this involves already knowing which files you want to look for.

If it was me, I would have a json table which holds the numbers of each level

e.g. 

{"1":1, "2":2, "3":3, ...etc..., "50":50}

Decode that to a Lua table:

loadFile = function( filename, base ) -- set default base dir if none specified if not base then base = system.DocumentsDirectory; end -- create a file path for corona i/o local path = system.pathForFile( filename, base ) -- will hold contents of file local contents -- io.open opens a file at path. returns nil if no file found local file = io.open( path, "r" ) if file then -- read all contents of file into a string contents = file:read( "\*a" ) io.close( file ) -- close the file after using it else print("defaulting to ResourceDirectory") jsonDefaulted = true local path2 = system.pathForFile( filename, system.ResourceDirectory ) local file2 = io.open(path2, "r") if file2 then contents = file2:read( "\*a" ) io.close (file2) end end return contents end local myTable = json.decode(loadFile("myData.json", system.DocumentsDirectory ))

and then when you want to choose a level just pick one of them at random as you said before. I would use math.randomseed(os.time()) to make it more randomised:

math.randomseed(os.time()) local myLevelNum = math.random(1, #myTable)

This would give you a number from 1, 50

Lets’s say it returned 34, so now you can go to level 34. However it sounds like you don’t want to be able to pick level 34 again? No problem, just remove number 34 from the table (and resave to the json file if it needs to be permanently removed from play).

table.remove(myTable, myLevelNum)

saveData = function(saveTable, fileName)

    local savePath = system.pathForFile(fileName, system.DocumentsDirectory )

    local saveFile = io.open(savePath, “w”)

    saveFile:write(json.encode(saveTable))                    

    io.close(saveFile)

    print("Saved "…fileName)

end

saveData(myTable, myData.json)

The next time you call math.random, the lua table will not have number 34 in it. The next time the app is started, the json file will also not have the number 34 in it.

I’m not sure if this is exactly what you were after, but hopefully it helps.

[sondre.lovhaug]

Thanks for the answer! This is basically the functionality I was looking for, I just have a few questions. What will happen when I add more levels to the game, 51 to 70 for example. I would just put them into the level folder, but then I would have to search for the new files and resave the table. Will all the levels in the table be replaced with these, and would you then have to play all the levels again? If so, is there an easy way to just remove all the completed levels from the table if I save them in another file?
Like
 

for i = 1, #completedLevels do for j = 1, #myTable do if myTable[j] == completedLevels[i] then table.remove(myTable, j) end end end

Sorry if this is very basic stuff, i’m not that experienced with coding.

[AlanPlantPot]

I have a function to check the contents of the folder:

function fileExists(theFile) local filePath = system.pathForFile(theFile, system.TemporaryDirectory) local results = false if filePath == nil then return false else local file = io.open(filePath, "r") --If the file exists, return true if file then io.close(file) results = true end return results end end

but to be honest, this involves already knowing which files you want to look for.

If it was me, I would have a json table which holds the numbers of each level

e.g. 

{"1":1, "2":2, "3":3, ...etc..., "50":50}

Decode that to a Lua table:

loadFile = function( filename, base ) -- set default base dir if none specified if not base then base = system.DocumentsDirectory; end -- create a file path for corona i/o local path = system.pathForFile( filename, base ) -- will hold contents of file local contents -- io.open opens a file at path. returns nil if no file found local file = io.open( path, "r" ) if file then -- read all contents of file into a string contents = file:read( "\*a" ) io.close( file ) -- close the file after using it else print("defaulting to ResourceDirectory") jsonDefaulted = true local path2 = system.pathForFile( filename, system.ResourceDirectory ) local file2 = io.open(path2, "r") if file2 then contents = file2:read( "\*a" ) io.close (file2) end end return contents end local myTable = json.decode(loadFile("myData.json", system.DocumentsDirectory ))

and then when you want to choose a level just pick one of them at random as you said before. I would use math.randomseed(os.time()) to make it more randomised:

math.randomseed(os.time()) local myLevelNum = math.random(1, #myTable)

This would give you a number from 1, 50

Lets’s say it returned 34, so now you can go to level 34. However it sounds like you don’t want to be able to pick level 34 again? No problem, just remove number 34 from the table (and resave to the json file if it needs to be permanently removed from play).

table.remove(myTable, myLevelNum)

saveData = function(saveTable, fileName)

    local savePath = system.pathForFile(fileName, system.DocumentsDirectory )

    local saveFile = io.open(savePath, “w”)

    saveFile:write(json.encode(saveTable))                    

    io.close(saveFile)

    print("Saved "…fileName)

end

saveData(myTable, myData.json)

The next time you call math.random, the lua table will not have number 34 in it. The next time the app is started, the json file will also not have the number 34 in it.

I’m not sure if this is exactly what you were after, but hopefully it helps.

[sondre.lovhaug]

Thanks for the answer! This is basically the functionality I was looking for, I just have a few questions. What will happen when I add more levels to the game, 51 to 70 for example. I would just put them into the level folder, but then I would have to search for the new files and resave the table. Will all the levels in the table be replaced with these, and would you then have to play all the levels again? If so, is there an easy way to just remove all the completed levels from the table if I save them in another file?
Like
 

for i = 1, #completedLevels do for j = 1, #myTable do if myTable[j] == completedLevels[i] then table.remove(myTable, j) end end end

Sorry if this is very basic stuff, i’m not that experienced with coding.