Lua Programming Help Thread

[the undead]

How would I open a file with a number, then subtract a number from the origianol number or add to the number?

like if some one gets aquestion right, lua opens the file then add to the number that is in the text document.

[Grimfate126]

How would I open a file with a number, then subtract a number from the origianol number or add to the number?

like if some one gets aquestion right, lua opens the file then add to the number that is in the text document.

file = io.open("testRead.txt","r")
score = file:read() -- will read line 1 of the file --
file:close()

file = io.open("testRead.txt","w")


if (question is right) then
score = score + 1
file:write(score)
end

-- at the end of code --

file:close()

[the undead]

Ok thanks ill tell you if it works

[yaustar]

is there a file number limiter in lua?

I know there is a file size limiter but what about file number? I tried to load 100 sequenced .png (all 480x272) files and it gave me an error saying load failed. I thought it exceeded the file size limit so i tried 100 sequenced .jpgs. It didn't gave me the error but it froze up and crash. Then i tried 20 but it still crash. The most i could get is like 10 or so. I have checked the total size of all my pngs and it's less than 2mb. I used some script to check my free memory and it said i had 8MB free without loading all the images. :Argh:

I have an OGG on playback in my script by the way. It may affect it?

Can someone tell me workaround for this? I've seen people adding a lot sprites into one png but can someone tell me an example on how to do this, for say 10 x 10 images? I am currently using a .pkg file and extracting sprites out to load it.

Please help me. Thanks :)

No, but there is a memory limit of 8mb as you just said. As images are loaded to memory, they are loaded in as a RAW format (think BMP). The fact the images as .jpgs/.pngs in total are less then 2mb is irrelevant, it's the size of the images in memory is what counts here.

[the undead]

Thanks it works!

[Grimfate126]

Thanks it works!

no prob. i actually though it wouldnt work, but meh. ;)

[the undead]

Ok, now I need to lnow how to open two files read one. close it then write that to the other file

[Access_Denied]

You should learn how to do some things by yourself. Check out this tutorial.

[the undead]

You should learn how to do some things by yourself. Check out this tutorial.

I know about that tut ive been reading it , ive been teaching myself this stuff, I wouldnt have asked if I found it.....

[Grimfate126]

Ok, now I need to lnow how to open two files read one. close it then write that to the other file

simple. same concept, just two files.

file1 = io.open("name1.txt", "r")
data = file1:read()
file1:close()

file2 = io.open("name2.txt", "w")
file2:write(data)
file2:close()

[1337PSPer]

is there a way to make a counter go in seconds not milseconds any help would be great

[Grimfate126]

is there a way to make a counter go in seconds not milseconds any help would be great

well, there are 1000 milliseconds in a second so:

timer = Timer.new()

timer:start()

while true do

seconds = math.floor(timer:time()/1000)

screen:print(5,5,"seconds ="..seconds, color)

screen.waitVblankStart()
screen:flip()
end

you just take the time and divide it by 1000 and round it down to an int. (otherwise it will say like: seconds = 1.3456 etc.)

BTW, math.floor rounds a number down. so 1.3456 will become 1, until 1.3456 goes up to above 2. then it will be 2.

[1337PSPer]

thx it was the math.floor part i needed i worked out the divide part
-= Double Post =-
what would be good colision code if i want to know when the two images(same size) over lap i don't want them to need to be exactly overlaping i'm making a game that u shoot stuff

[SG57]

Theres plenty of collision mech's out there. I remember i ported a C collision mech to LUA... search for a thread called collison...

[1337PSPer]

i had a look at that code it's not what i'm looking for thats for walking in to walls and stuff. what i'm looking for is a way of saying "if middle of picture1 is touching any of picture2 then ..."
both pictures are "20 high" and "31 wide"

[JoeDaStudd]

try this

Pic={}
pic[1]={pic=Image.load("picture1.png"),x=0,y=0,midx=pic[1].x+15,midy=pic[1].y+10}
pic[2]{pic=Image.load("picture2.png"),x=180,y=100,farx=pic[2].x+31,fary=pic[2].y+20}

--in main loop
if pic[1].midx>=pic[2].x and pic[1].midx<=pic[2].farx then
if pic[1].midy>=pic[2].y and pic[1].midx<=pic[2].fary then
screen:print(0,0,"Found you",blue)
end
end

That should work if you also have the code to move pic[1].x and pic[1].y around.
If it still doesnt work then i did something wrong...

[1337PSPer]

error:main.lua:8: attempt to index global "duck" (a nil value)

line 8: duck[1]={pic=Image.load("pics/duck_1.png"),x=25,y=53,fa rx=duck[1].x+31,fary=duck[1].y+20}
what did i do wrong

EDIT:
fixed that error
now this one
error:main.lua:8: attempt to index field "?" (a nil value)
line 8 hasn't change from above

[trex6662k5]

screen.waitVblankStart()
Am I right in thinking thats keeping the image refreshing in sync with the PSPs refreshrate? Like VSync for the pc. If so, Why would anyone care about tearing on a PSP?
Ive read that its keeps the image on screen but thats screen.flip() right?
Removing screen.waitVblankStart() from my program, I saw no differences except for a healthy performance boost. Just like disabling VSync on the pc.

[JoeDaStudd]

ok remove the farx and far y from the duck[1] {}
and add them below
so it looks something like this

duck[1]={pic=Image.load("pics/duck_1.png"),x=25,y=53}
farx=duck[1].x+31
fary=duck[1].y+20

[1337PSPer]

ok that fixed that error now i get this 1
Error: main.lua:86: bad argument #2 to 'blit' (image expected, got table)
line 86: screen:blit(duck[1].x, duck[1].y, duck[1])
edit fixed that
now when i click x i get
Error: main.lua:167: attempt to compare number with nil

[JoeDaStudd]

this line

screen:blit(duck[1].x, duck[1].y, duck[1])

doesnt include a pic is and is what caused that error.
duck[1] is the name of the table which you are telling it to blit (print to screen as a pic)
I think you just forgot to write
duck[1].pic
so that line would be

screen:blit(duck[1].x, duck[1].y, duck[1].pic)

Ps. soz for the number of edits ive done to this post

[1337PSPer]

it's cool btw i'm putting u in the credits for all your help
fixed that
now when i click x i get
Error: main.lua:167: attempt to compare number with nil

[JoeDaStudd]

it's cool btw i'm putting u in the credits for all your help

Thanks
What code is on line 167?
EDIT; if you what I can take a quick look at the code for you if u attach it, that way i can sort out most of the problems in one go

[myschoo]

[rant]
i HATE it when some people have to do EVERYTHING by the tutorials.. geez, use YOUR brain for once! ever heard of the saying "there is more than one way to do something" ? LISTEN to it... [/rant] (not talking about you myscoo, just using you as an example. )

anyways, myscoo try different things. try all ideas you get, one might help your performance a lot.

omg im still learning lua! :/

[dracule]

is there a script/function to tell of the variable is odd or even? i need this:
if variable is odd then do this, if not do this.

[yaustar]

if 1 == math.mod(Number, 2) then
-- number is odd
else
-- number is even
end

[Grimfate126]

omg im still learning lua! :/

so am i. so is shine. so is pspmillionaire. so is bill gates (im guessing.) thats not good enough of an excuse to not try something by yourself. i wasn't flaming you. just because one way works, doesnt mean thats the best way.

believe me, im still like that sometimes, so i have no right to talk to you like i never do it, but im trying my best to quit that habit, and so should everyone.

[the undead]

simple. same concept, just two files.

file1 = io.open("name1.txt", "r")
data = file1:read()
file1:close()

file2 = io.open("name2.txt", "w")
file2:write(data)
file2:close()

Didnt work, so I tryed altering it but still dosent work..here is what I did

file = io.open("score.txt", "r")
score = file:read()
file:close()
file:close()
file = io.open("Hscore.txt", "r")
H = file:read()
file:close()
file = io.open("Hscore.txt", "w")


if score >= H then
H = file:write(score)
end
file:close()

[LMelior]

What doesn't work about it? You have two file:close() lines in there, did it give you an error for that? Also, if you're reading a number, you might have to use file:read("*n"). That's all I can see wrong with it.

[the undead]

I dont know, illl try that n thing
-= Double Post =-
I get this after adding the n stuff