Lua Programming Help Thread

[myschoo]

screenwidth = 480 - player:width()
screenheight = 272 - player:width()

im not a big pro but is this OK?

btw. i found what was the problem of this code...

Music.playFile("music.xm ", true)

i just had to put it outside main loop :o

[-Marshall-]

screenwidth = 480 - player:width()
screenheight = 272 - player:width()

im not a big pro but is this OK?

yeah thats ok but now i have a new error

System.usbDiskModeActivate()
line = Image.load("line.png")
player = Image.load("player.png")
linee = Image.load("line1.png")


Player = { }
Player[1] = { x = 10, y = 75 }
playerHeight = 60
playerWidth = 66
oldx = Player.x
oldy = Player.y
screenwidth = 480 - player:width()
screenheight = 272 - player:width()

--Colisions
function collisionCheck(object)
if (Player.x + playerWidth > linem.x) and (Player.x < linemx + linem.width) and (Player.y + playerHeight > linem.y) and (Playery < linem.y + linem.height) then
Player.x = oldx
Player.y = oldy
end
end


 
linem = { }
linem[1] = { x = 0, y = 150 }

while true do

pad = Controls.read()
screen:clear()

screen:blit(0,50,linee)

screen:blit(0,150,line)


--check collision for line
collisionCheck(linem[1])



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

if pad:left() and Player[1].x > 0 then
Player[1].x = Player[1].x - 4
end

if pad:right() and Player[1].x < screenwidth then
Player[1].x = Player[1].x + 4
end

if pad:up() and Player[1].y > 0 then
Player[1].y = Player[1].y - 4
end

if pad:down() and Player[1].y < screenheight then
Player[1].y = Player[1].y + 4
end

if pad:start() then break end
screen.waitVblankStart()
screen.flip()
end

error:attempt to perform arithmetic on global 'X' and sometimes it says 'player x' insted of 'x' i under stand what its telling me but i dont understand why its telling me :P

[Access_Denied]

yeah thats ok but now i have a new error

System.usbDiskModeActivate()
line = Image.load("line.png")
player = Image.load("player.png")
linee = Image.load("line1.png")


Player = { }
Player[1] = { x = 10, y = 75 }
playerHeight = 60
playerWidth = 66
oldx = Player.x
oldy = Player.y
screenwidth = 480 - player:width()
screenheight = 272 - player:width()

--Colisions
function collisionCheck(object)
if (Player.x + playerWidth > linem.x) and (Player.x < linemx + linem.width) and (Player.y + playerHeight > linem.y) and (Playery < linem.y + linem.height) then
Player.x = oldx
Player.y = oldy
end
end


 
linem = { }
linem[1] = { x = 0, y = 150 }

while true do

pad = Controls.read()
screen:clear()

screen:blit(0,50,linee)

screen:blit(0,150,line)


--check collision for line
collisionCheck(linem[1])



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

if pad:left() and Player[1].x > 0 then
Player[1].x = Player[1].x - 4
end

if pad:right() and Player[1].x < screenwidth then
Player[1].x = Player[1].x + 4
end

if pad:up() and Player[1].y > 0 then
Player[1].y = Player[1].y - 4
end

if pad:down() and Player[1].y < screenheight then
Player[1].y = Player[1].y + 4
end

if pad:start() then break end
screen.waitVblankStart()
screen.flip()
end

error:attempt to perform arithmetic on global 'X' and sometimes it says 'player x' insted of 'x' i under stand what its telling me but i dont understand why its telling me :P

You have this line:

oldx = Player.x
oldy = Player.y

and this line

Player.x = oldx
Player.y = oldy

But you use neither of these variables, and you didn't define any of them. You defined each one of them as being equal to an undefined variable. It's a giant loop. Just take them out, or do something like

Player.x = 0
Player.y = 0
oldx = 0
oldy = 0

Just to define them in some way.

[LMelior]

You also changed the code inside the collisionCheck function. Change it back.

[rybarnes]

I have a game where I print a 'bottle' to the screen when x is pushed, and it moves across the screen. Now I am having an issue being able to stop printing it once its x cord hits 0, so you can send another bottle down. I have the code to print it in a function, so its not working out to well. Heres my code.

 
function bottleSpawn()
randSpeed = math.random(2,6)

if bottleCheckTop == true then
bottle[1].x = bottle[1].x - randSpeed
screen:blit(bottle[1].x, bottle[1].y, Bottle)
end

--and...

if pad:cross() and player.y == -20 then
bottleCheckTop = true

Any ideas to make iit possible to send more then one 'bottle' at a time?

(Seems like such a simple problem, but I just can't figure it out. :rtfm: (What does RTFM mean anyways?))

[Bronx]

try maybe

i = 1

function bottleSpawn()
randSpeed = math.random(2,6)

if bottleCheckTop == true then
bottle[i].x = bottle[i].x - randSpeed
screen:blit(bottle[i].x, bottle[i].y, Bottle)

if bottle[i].x == 0 then
i = i+ 1
end
end

BTW, you need and 'end' here:

if pad:cross() and player.y == -20 then
bottleCheckTop = true

[psphacker12.]

I have a game where I print a 'bottle' to the screen when x is pushed, and it moves across the screen. Now I am having an issue being able to stop printing it once its x cord hits 0, so you can send another bottle down. I have the code to print it in a function, so its not working out to well. Heres my code.

 
function bottleSpawn()
randSpeed = math.random(2,6)

if bottleCheckTop == true then
bottle[1].x = bottle[1].x - randSpeed
screen:blit(bottle[1].x, bottle[1].y, Bottle)
end

--and...

if pad:cross() and player.y == -20 then
bottleCheckTop = true

Any ideas to make iit possible to send more then one 'bottle' at a time?

(Seems like such a simple problem, but I just can't figure it out. :rtfm: (What does RTFM mean anyways?))

read the f*ckin manual.

[myschoo]

help me im getting this error quite alot:

<eof> expected near "end"

what does it mean ?

[rybarnes]

help me im getting this error quite alot:

<eof> expected near "end"

what does it mean ?

You have one to many ends in your code.

[Access_Denied]

help me im getting this error quite alot:

<eof> expected near "end"

what does it mean ?

It means that somewhere you forgot to put an 'end'. Probably at the end of a function or if/then statement.

[Grimfate126]

It means that somewhere you forgot to put an 'end'. Probably at the end of a function or if/then statement.

actually, it means the opposite. you have an extra end somewhere. if you needed an end, it would say:

error: line: 'end' expected to close whatever.. on line ..whatever.

[myschoo]

thx guys...it was true i removed end and it worked

[%chrono trigger%]

ok so i starte to code my game from the ground up again and i am just trying a simple code i made heres the error i get:
error: script.lua:6: function arguments wxpected near 'while'
heres my code:

red = Color.new(0,0,255)
main1 = Image.load("main1.png")
screen:print(0,0,"injustice",red)
screen.flip()
screen:clear
while true do
screen:clear
screen:blit(0,0,main1)
screen:clear
screen.waitVblankStart()
end 
end

i dont know whats wrong again. please dont flame me i just cant get this programing thing down but im trying

[Grimfate126]

ok so i starte to code my game from the ground up again and i am just trying a simple code i made heres the error i get:
error: script.lua:6: function arguments wxpected near 'while'
heres my code:

red = Color.new(0,0,255)
main1 = Image.load("main1.png")
screen:print(0,0,"injustice",red)
screen.flip()
screen:clear
while true do
screen:clear
screen:blit(0,0,main1)
screen:clear
screen.waitVblankStart()
end 
end

i dont know whats wrong again. please dont flame me i just cant get this programing thing down but im trying

youre not putting () after screen:clear(). it should be:

red = Color.new(0,0,255)
main1 = Image.load("main1.png")
screen:print(0,0,"injustice",red)
screen.flip()
screen:clear()
while true do
screen:clear()
screen:blit(0,0,main1)
screen:clear()
screen.waitVblankStart()
end 
end

btw, when it says function arguments, its usually referring to the ().

[Access_Denied]

And you have to many 'end's.

[%chrono trigger%]

yeah i know i have to many ends i just typed one more its not in my code and with the function arguments is it always parentheses or can it be something else? i read in a error index that thats all it is plus thank you all for being patient with me and my noob questions

[Grimfate126]

yeah i know i have to many ends i just typed one more its not in my code and with the function arguments is it always parentheses or can it be something else? i read in a error index that thats all it is plus thank you all for being patient with me and my noob questions

its the parenthesis most of the time. im not sure though.

[%chrono trigger%]

are there multiple reasons for why after you load the script it just stays black? or is that becasue of one main thing (error; mistake in the code)

[Grimfate126]

and is there something generic that you always do if the screen just stays black? or are there multiple reasons for that?

say what? in laymans terms please. ;)

[%chrono trigger%]

i update my last post
-= Double Post =-
i updated my last post

[Altair]

are there multiple reasons for why after you load the script it just stays black? or is that becasue of one main thing (error; mistake in the code)

Well ofcourse there is an error in the code if the screen stays black. Or your screen just broke...

Also watch out that you don't devide something by zero. Then the screen will also stay black and the PSP will crash. This is sometimes harder to see, because there isn't an obvious mistake. You'll have to check if it's possible that the denominator (that's what its caled right?) becomes zero yourself.

[Fuzzie360]

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 :)

[myschoo]

pls help i cant figure out whats the problem with this code:

white = Color.new(255,255,255)

blockA = Image.createEmpty(480,1)
blockA:clear(white)

blockB = Image.createEmpty(480,1)
blockB:clear(white)

blockC = Image.createEmpty(1,272) 
blockC:clear(white)

blockD = Image.createEmpty(1,272)
blockD:clear(white)

BlockA = { x = 0, y = 0, height = blockA:height(), width = blockA:width() }

BlockB = { x = 0, y = 271, height = blockB:height(), width = blockB:width() }

BlockC = { x = 0, y = 0, height = blockC:height(), width = blockC:width() }

BlockD = { x = 479, y = 0, height = blockD:height(), width = blockD:width() }

player = Image.createEmpty(32,32)
player:clear(white)

Player = { x = 30, y = 100 }

playerHeight = 32
playerWidth = 32


function movePlayer()
pad = Controls.read()
if pad:right() then
Player.y = Player.y + 5
end
if pad:left() then
Player.y = Player.y - 5
end
if pad:down() then
Player.x = Player.x + 5
end
if pad:up() then
Player.x = Player.x - 5
end
end

function collisionCheck(object) 
if (Player.x + playerWidth > object.x) and (Player.x < object.x + object.width) and (Player.y + playerHeight > object.y) and (Player.y < object.y + object.height) then
Player.x = oldx
Player.y = oldy
end 
end

while true do

oldx = Player.x
oldy = Player.y
screen:clear()

collisionCheck(BlockA)
collisionCheck(BlockB)
collisionCheck(BlockC)
collisionCheck(BlockD)

screen:clear()

movePlayer()

screen:blit(Player.y,Player.x,player)

screen:blit(BlockA.x,BlockA.y,blockA)

screen:blit(BlockB.x,BlockB.y,blockB)

screen:blit(BlockC.x,BlockC.y,blockC)

screen:blit(BlockD.x,BlockD.y,blockD)

screen.waitVblankStart()
screen.flip()
end

it ment to stop player to get out from the screen but it doesnt work... can figure out what the prob :Cry: HELP

[Freshmilk]

i don't see any problems, but i havn't slept in 27 hours, so obviously my judgement will be affected...

[myschoo]

me to! i cant see any problems but it still doesnt work!!

[LMelior]

Didn't I tell you to look at your code and think logically what it will do? ;)

I was going to tell you exactly what's wrong, but I don't feel like explaining. So I'll give you a hint: the order that you do things in your loop is the problem.

[Access_Denied]

pls help i cant figure out whats the problem with this code:

white = Color.new(255,255,255)

blockA = Image.createEmpty(480,1)
blockA:clear(white)

blockB = Image.createEmpty(480,1)
blockB:clear(white)

blockC = Image.createEmpty(1,272) 
blockC:clear(white)

blockD = Image.createEmpty(1,272)
blockD:clear(white)

BlockA = { x = 0, y = 0, height = blockA:height(), width = blockA:width() }

BlockB = { x = 0, y = 271, height = blockB:height(), width = blockB:width() }

BlockC = { x = 0, y = 0, height = blockC:height(), width = blockC:width() }

BlockD = { x = 479, y = 0, height = blockD:height(), width = blockD:width() }

player = Image.createEmpty(32,32)
player:clear(white)

Player = { x = 30, y = 100 }

playerHeight = 32
playerWidth = 32


function movePlayer()
pad = Controls.read()
if pad:right() then
Player.y = Player.y + 5
end
if pad:left() then
Player.y = Player.y - 5
end
if pad:down() then
Player.x = Player.x + 5
end
if pad:up() then
Player.x = Player.x - 5
end
end

function collisionCheck(object) 
if (Player.x + playerWidth > object.x) and (Player.x < object.x + object.width) and (Player.y + playerHeight > object.y) and (Player.y < object.y + object.height) then
Player.x = oldx
Player.y = oldy
end 
end

while true do

oldx = Player.x
oldy = Player.y
screen:clear()

collisionCheck(BlockA)
collisionCheck(BlockB)
collisionCheck(BlockC)
collisionCheck(BlockD)

screen:clear()

movePlayer()

screen:blit(Player.y,Player.x,player)

screen:blit(BlockA.x,BlockA.y,blockA)

screen:blit(BlockB.x,BlockB.y,blockB)

screen:blit(BlockC.x,BlockC.y,blockC)

screen:blit(BlockD.x,BlockD.y,blockD)

screen.waitVblankStart()
screen.flip()
end

it ment to stop player to get out from the screen but it doesnt work... can figure out what the prob :Cry: HELP

Why do all that collision checking, when you can just put:

if pad:left() and player.x > 0 then
player.x = player.x - 2
end

Just do that for all the sides. It's much easier.

[myschoo]

Didn't I tell you to look at your code and think logically what it will do? ;)

I was going to tell you exactly what's wrong, but I don't feel like explaining. So I'll give you a hint: the order that you do things in your loop is the problem.

wow ur my master i got it :)
-= Double Post =-

Why do all that collision checking, when you can just put:

if pad:left() and player.x > 0 then
player.x = player.x - 2
end

Just do that for all the sides. It's much easier.

im learning by evilmana tuts and thats how they explained it...:)

[Grimfate126]

wow ur my master i got it :)
-= Double Post =-


im learning by evilmana tuts and thats how they explained it...:)

[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.

[Access_Denied]

Read tutorial 7 of ProgramLua. That'll help you so your player doesn't go off screen.