Lua Programming Help Thread

[FaT3oYCG]

could i see the section of code that that part is in, and the table that the data is being loaded from again, as it is in the script

[andyauff]

Okay.

locations = {}

while true do
	pad = Controls.read()
	screen:clear()
	dx = pad:analogX()
	dy = pad:analogY()

    if gamestate == "game" then
        if locations ~= nil then
	    for i = 1, table.getn(locations) do
	       screen:blit(locations[i].x,locations[i].y,dot)
            end
        end
   elseif gamestate == "menu" then
           pad = Controls.read()
        
        --if user is loading... took that out for this example
        if pad:square() and not oldpad:square() then
              System.usbDiskModeDeactivate()
              loadFile = io.open("Saved Sets/" .. loadFile2 .. ".txt","r")
              number = 0

              for line in loadFile:lines() do
                  number = number + 1
              end

              for j = 1, math.floor(number/2)*2, 2 do
                  xc = loadFile:read()
                  yc = loadFile:read()

                  table.insert(locations,{x=xc,y=yc})
              end

              loadFile:close()

              System.usbDiskModeActivate()
              gamestate = "game"
              pausestate = "select"
        end
   end
end

That's the heart of it. It's taken from throughout the entire script but hopefully it makes sense. I can give you the whole thing if you want, but it's probably not necessary.

[FaT3oYCG]

hmm you know this part

xc = loadFile:read()
yc = loadFile:read()

could you check for me by printing the data to the screen before continuing what these are, because i think that what you are doing is this

xc = 4, 10
yc = 4, 10

so calling a screen:blit() with those valuse it is causing the loop in gettable error where 4, 10 is the value

also try using the code that i made for you it does work, it loads and saves files easier, and you wouldnt get that error

if what i said is the case then it would be easier to use the code that i made that i know works, than to recode what you have to work, because it isnt the right way to load data from a table anyway, not saying mine is the right way but it is better than the current method that you are using

thanks

[andyauff]

Printing them told me that they were nil. But I used the way you showed me a few posts ago, and it worked like a charm. Thanks a lot!

[Nielkie]

Okay.

              for j = 1, math.floor(number/2)*2, 2 do
                  xc = loadFile:read()
                  yc = loadFile:read()

                  table.insert(locations,{x=xc,y=yc})
              end

You are still not reading the file correctly.

loadFile:read() is returning "x,y", correct? (where x and y are the co-ordinates in each case) So, you are basically stating:

xc = "x,y"
yc = "x,y"

Even if you stated:

xc,yc = "x,y"

It still wouldn't work because Lua cannot convert "x,y" (A string) into a group of numbers.

You would need something like this:

loc = loadFile:read()
xc = string.sub(loc,1,string.find(loc,",") - 1)
yc = string.sub(loc,string.find(loc,",") + 1)

But even that wouldn't work because you are just reading the the first line over and over, you need to move forward a line every time. So you would need something like this: (I'm not sure what the for loop looping through in your code, but this is general)

        if pad:square() and not oldpad:square() then
              for line in io.lines("Saved Sets/" .. loadFile2 .. ".txt") do
                      table.insert(locations,{x=string.sub(line,1,string.find(line,",") - 1),y=string.sub(line,string.find(line,",") + 1)})
              end

              System.usbDiskModeDeactivate()
              System.usbDiskModeActivate()
              gamestate = "game"
              pausestate = "select"
        end

EDIT: Oh, I see. You are iterating in groups of 2, so your files are just stored as a list of numbers. in that case:

              local n = 0
              for line in io.lines("Saved Sets/" .. loadFile2 .. ".txt") do
                      n = n + 1
                      if math.floor(n / 2) * 2 == n then
                                locations[n / 2 + 1].y = line
                      else
                                locations[(n - 1) / 2 + 1] = {x = line}
                      end
              end

Or if you are adding to an existing list:

              local p = table.getn(locations)
              local n = 0
              for line in io.lines("Saved Sets/" .. loadFile2 .. ".txt") do
                      n = n + 1
                      if math.floor(n / 2) * 2 == n then
                                locations[p + n / 2 + 1].y = line
                      else
                                locations[p + (n - 1) / 2 + 1] = {x = line}
                      end
              end

[FaT3oYCG]

Printing them told me that they were nil. But I used the way you showed me a few posts ago, and it worked like a charm. Thanks a lot!

no problem, glad it worked

[andyauff]

You are still not reading the file correctly.

loadFile:read() is returning "x,y", correct? (where x and y are the co-ordinates in each case) So, you are basically stating:

xc = "x,y"
yc = "x,y"

Even if you stated:

xc,yc = "x,y"

It still wouldn't work because Lua cannot convert "x,y" (A string) into a group of numbers.

You would need something like this:

loc = loadFile:read()
xc = string.sub(loc,1,string.find(loc,",") - 1)
yc = string.sub(loc,string.find(loc,",") + 1)

But even that wouldn't work because you are just reading the the first line over and over, you need to move forward a line every time. So you would need something like this: (I'm not sure what the for loop looping through in your code, but this is general)

        if pad:square() and not oldpad:square() then
              for line in io.lines("Saved Sets/" .. loadFile2 .. ".txt") do
                      table.insert(locations,{x=string.sub(line,1,string.find(line,",") - 1),y=string.sub(line,string.find(line,",") + 1)})
              end

              System.usbDiskModeDeactivate()
              System.usbDiskModeActivate()
              gamestate = "game"
              pausestate = "select"
        end

I see what you mean, but that would be if I had the x and y values on the same line in the file. The way I had it was an x value on the first line, y on the second, x on the third, y on the fourth, etc. But I'm using a completely different method now, thanks to FaT3oYCG, so it's all good. But thanks :).

[Nielkie]

I see what you mean, but that would be if I had the x and y values on the same line in the file. The way I had it was an x value on the first line, y on the second, x on the third, y on the fourth, etc. But I'm using a completely different method now, thanks to FaT3oYCG, so it's all good. But thanks :).

I updated my post when I saw what the for loop was doing. Anyway, it's always nice to know the reason for a problem.

[andyauff]

I updated my post when I saw what the for loop was doing. Anyway, it's always nice to know the reason for a problem.

Okay, thanks Nielkie. Yes, I agree, it is certainly important to understand the problem.

[waywardson]

hey would anyone know how to get a decimal converted to a whole number ?
for example i get 88.3333333333333 but i want it to print 88

[andyauff]

math.floor(83.33333333333 33)

I'm pretty sure that's it.

[waywardson]

thanks andyauff :]]

[andyauff]

No problem.

[FaT3oYCG]

oops ill put this in in just a moment

EDIT: there you go

function round_number(number)
check_number_full = string.format("%.1f", number)
check_number_single = string.sub(check_number_full, -1)
if check_number_single < 5 then
return math.floor(number)
else
return math.ceil(number)
end
end

if the number after the decimal is smaller than 5 then it will round down like it would in propper maths and if it is 5 or above then it will round up

e.g. 5.27577 woud return 5 and 5.78435 would return 6

[andyauff]

Yeah, I thought there was a function for rounding up too. That's why I said I was pretty sure. math.floor worked because you were rounding down. Thanks for adding that function, FaT3oYCG.

[waywardson]

oops ill put this in in just a moment

EDIT: there you go

function round_number(number)
check_number_full = string.format("%.1f", number)
check_number_single = string.sub(check_number_full, -1)
if check_number_single < 5 then
return math.floor(number)
else
return math.ceil(number)
end
end

if the number after the decimal is smaller than 5 then it will round down like it would in propper maths and if it is 5 or above then it will round up

e.g. 5.27577 woud return 5 and 5.78435 would return 6

thanks :]
the math.floor worked for me but its always good to see exactly how it works thanks

[FaT3oYCG]

yeah i just though id put that in because it can be used all the time, ill explain the functions for you aswell

math.floor(number) - all this does is remove any decimals on the number after the point, to return the whole number

math.ceil(number) - all this does is add one to the number and then remove any decimals after the point, to return a whole number

i made that function because it rounds depending on the decimal not by just rounding up or down all of the time

[TurtlesPwn]

Wow. That is a horrible rounding function, and you explained what math.floor and ceil do incorrectly. For negative numbers, your explanation no longer holds true.
Also, nonsucky rounding function:

function math.round(n)
return math.floor(n+0.5)
end

[michaelp]

Doesn't math.floor round down to the nearest whole number and math.ceil round up?

[waywardson]

Doesn't math.floor round down to the nearest whole number and math.ceil round up?

yes but the way he just wrote it is that it adds .5 to any of ur decimals and rounds down... so if ur deciam is say 1.5 it would be 1.5 +.5 witch = 2 and 2 rounds to 2... if it were 1.3 then it would be 1.3 +.5 witch = 1.8 witch with math.floor would round to 1 so..it still works :P cool and simple rounding function :}]]

[TurtlesPwn]

michaelp - yes. that would be what it does. please refer to above posts (although incorrect it still gets the point across) and http://lua-users.org/wiki/TutorialDirectory before asking more questions.

[FaT3oYCG]

lol

everyday when im walking down the street, every turtle that i meet says, its a simple message and it comes from the shell, you help people and then i pwn you, hey!!!. every day when im ...

thanks lol

yeah my function sux, but i did make it a long time ago

oh and

math.floor (x)
Returns the largest integer smaller than or equal to x.

math.ceil (x)
Returns the smallest integer larger than or equal to x.

[j3r3mie]

CAn someone can show me how to use this function in he Lua Player HM.

System.usbDevUMD()

If I try it like that :

if pad:cross() then
System.usbDevUMD()
end

Nothing happen when i push X. CAn someone help me please.

[FaT3oYCG]

System.usbDevUMD() sets the usb to the umd
System.diskModeActivate() still turns it on so

if pad:cross() then
System.usbDevUMD()
System.diskModeActivate()
end

[j3r3mie]

Attemp to call field 'diskmodeActivate" (a nil value)

Do you know what does that means ?

[FaT3oYCG]

sorry

System.usbDiskModeActivat e()

[j3r3mie]

Thanks. For the fastest with anwser me. What abotu that one.

I'll want to creat a drum app. I wnt to load my sound and associate them to a name. Then I want to, if i push X, per exemple, play the sound associate to "kick" bu tonly once. Do u know how i have to do that.

I alerdy try but i wasn'n able.

[PSProgramer]

you need to put

oldpad = Controls.read()

at the top of your code by like the colors, or what not and put

if pad:cross() and oldpad:cross() ~= pad:cross() then

before the sound you want to be heard

and finally right before the end of your code put

oldpad=pad

that should work, Please correct me if I'm wrong Fat3oYCG

also I think your idea sounds cool, keep up the good work

[TurtlesPwn]

PSProgrammer - that gets the job done, but personally I believe it is a horrible way to accomplish that job.

Replace:

pad = Controls.read()

with:

oldpad = pad
pad = Controls.read()

and then for button press detection, use:

if pad:cross() and not oldpad:cross() then

Basically, that will make the logic of it say, if cross has been pressed but it was not pressed last loop (aka it JUST got pushed down) then blah
If you want to change that logic to, if cross was pressed down but just got released then blah, then do this:

if oldpad:cross() and not pad:cross() then

[KleptoOne]

TurtlesPwn - that gets the job done, but personally I believe it is a horrible way to accomplish that job.

Replace:

Dpad = Controls.read()

with:

oldDpad = Dpad
Dpad = Controls.read()

and then for button press detection, use:

if Dpad:cross() and not oldDpad:cross() then

Basically, that will make the logic of it say, if cross has been pressed but it was not pressed last loop (aka it JUST got pushed down) then blah
If you want to change that logic to, if cross was pressed down but just got released then blah, then do this:

if oldDpad:cross() and not Dpad:cross() then

Think about this before responding.