Lua Programming Help Thread

[TacticalPenguin]

Yea i took out a bunch of points and was gonna buy no pm flood limit then i remembered i get the discount for premium and 300k, so with the 26k i saved i stickied this and bumped the MDPR.

[GuitarGod1134]

Hello im making my game and im pretty much finished with area 1. I want my guy to be able to walk to the edge of the screen and then go to a new area but if i keep it in the same loop wouldnt it just load my area 1 background and stuff back onto the screen?? I heard people saying that break changes the control to a different loop so couldnt i do

while true do
-- bla bla this is area 1
if player.x == screen.x then
break
end
end

while true do
--now we are in area 2 ya ya bla bla



would that work?? im confused on how to make it load a level 2 or something? And what about sidescrolling how do i do that are there anymore tutorials besides evilmana?

[trex6662k5]

Im trying to complete a LUA script thats for the PSP thats able to remotely control foobar2000 though controlserver. Everything was going smoothly untill I started retreving tracklists.
Information sent gets split upon finding a "\n" for splitting lines and then retreving the data on those lines is done by finding a "|".
I just expect a number in the first field but sometimes the script jumps to a section in the line and adds that to the result...
For example: 6016016016016016016016016 01esk_-_excuses601601601
"601" is given to an inactive track on a playlist and "esk_-_excuses" happens to be the title of the track. But I specificly asked for the first field so I dont understand why the title is there. This tends to occur with large amount of data.

The socket gets polled for data all the time and data begins to get sorted when theres information.

if socket then
   incoming = socket:recv()
      if incoming ~= "" then
         values = splitString(incoming,"\n")
	 for key, value in values do
	    temp = splitString(value,"|")[1]

The function that stringsplits

function splitString(str, de)
	first = true
	parts = {}
	if de == ";" then
		str = string.gsub(str,";;","@£$&")
	end
	while true do
		s, e = string.find(str,de)
		if e then
			if not (first and string.sub(str,1,s-1) == "") then
				tmp = string.sub(str,1,s-1)
				if de == ";" then
					tmp = string.gsub(tmp,"@£$&",";;")
				end
				table.insert(parts,tmp)
			end
			str = string.sub(str,e+1)
			s = 1
			first = false
		else
			tmp = string.sub(str,1)
			if de == ";" then
				tmp = string.gsub(tmp,"@£$&",";;")
			end
			table.insert(parts,tmp)
		break
		end
	end
	return parts
end

[EminentJonFrost]

Hello im making my game and im pretty much finished with area 1. I want my guy to be able to walk to the edge of the screen and then go to a new area but if i keep it in the same loop wouldnt it just load my area 1 background and stuff back onto the screen?? I heard people saying that break changes the control to a different loop so couldnt i do

while true do
-- bla bla this is area 1
if player.x == screen.x then
break
end
end

while true do
--now we are in area 2 ya ya bla bla



would that work?? im confused on how to make it load a level 2 or something? And what about sidescrolling how do i do that are there anymore tutorials besides evilmana?

how about this:

blah = 1 -- this will be where the player currently is

while true...

...
if blah == 1 then
make this area appear
elseif blah == 2 then
make this area appear
end

...

end

try that. its pretty simple.

[GuitarGod1134]

ya i was thinking about throwing a variable in thanks ill try that out.

[emericaska8r]

ok, i would like to know if there is a function in lua that will get the integer part of an double (decimal). So if i had 48.65, I could convert this to just 48.
Hmmm, maybe i could just use like a rounding function...
is there any out there

ok, i found this
function math.round(num, idp) 
local mult = 10^(idp or 0) 
return math.floor(num * mult + 0.5) / mult 
end

idp being the number of decimals you want.

i guess, this works fine, for me so nvm, i was just wondering if there was any function already incorporated into lua

[Grimfate126]

ok, i would like to know if there is a function in lua that will get the integer part of an double (decimal). So if i had 48.65, I could convert this to just 48.
Hmmm, maybe i could just use like a rounding function...
is there any out there

ok, i found this
function math.round(num, idp) 
local mult = 10^(idp or 0) 
return math.floor(num * mult + 0.5) / mult 
end

idp being the number of decimals you want.

i guess, this works fine, for me so nvm, i was just wondering if there was any function already incorporated into lua

for your purpose, this should be fine:

math.floor(num)

that will mtake the decimal away. so 50.2 becomes 50, and 3.99 becomes 3.

[GuitarGod1134]

can i do if statements inside of if statments??? im trying to make it so that when my creature goes to the edge of the screen he enters a new area and not a new level. Im not sure how to add this without making it have to read a new lua file with a new loop. someone help!!1 my source is posted a couple pages back if anyone bothered to read it. im trying to do what eminent said.

[EminentJonFrost]

can i do if statements inside of if statments??? im trying to make it so that when my creature goes to the edge of the screen he enters a new area and not a new level. Im not sure how to add this without making it have to read a new lua file with a new loop. someone help!!1 my source is posted a couple pages back if anyone bothered to read it. im trying to do what eminent said.

yes, you can put if statements in others. however, i think it would be better if, instead of making millions of 'if's, do this:

if [whatever] and [whatever] then

that'll test both conditions in one 'if' statement. and its not limited to testing just two conditions either. so it could even be:

if [whatever] and [whatever] and [whatever] and [whatever] then

[GuitarGod1134]

Spoiler for My game:

-- Im Changing up Maze of Doom and I've been coming up with more ideas weekly so Im starting on this

-- time to declare some variables
--colors
green = Color.new(0, 255, 0)
red = Color.new(255, 0, 0)
black = Color.new(0, 0, 0)

--sprites
demon = Image.load("demon.png")
creature = Image.load("creature.png" )

--what area are u in???
currentarea = 0

--the width and height of screen
screenwidth = 480
screenheight = 272

-- the player looks in different directions right?
splayer = {}
--now hes looking straight
splayer[1] = Image.load("lL.png")
--now hes looking left
splayer[2] = Image.load("lR.png")
--now hes looking right
splayer[3] = Image.load("lU.png")
--now hes looking back
splayer[4] = Image.load("lD.png")

--now for the variable that makes his head turn .. literally
direction = 1

--the creature's health
chp = 500

--more sprites
bullet = Image.createEmpty(1,1)
bullet:clear(black)

--and the level we are on
level1 = Image.load("level1.png")


-- player's health and armor and the aliens'
health = 100
armor = 50
demonhp = 10

--how long it takes to reload
reload = Timer.new()

--the player's bullets
ammo = 1

-- some tables
Player = {}
Player[1] = {x=0, y=0}

-- your ammo
Bullet = {}
Bullet[1] = { x = Player[1].x, y = Player[1].y}

--the creatures table
creature = {}
creature[1] = { x = 10, y = 10 }

--whether the demon is alive or not
demonal = {}
demonal[1] = "true"
demonal[2] = "true"
demonal[3] = "true"
demonal[4] = "true"
demonal[5] = "true"
demonal[6] = "true"

-- the demon tables
demon = {}
demon[1] = {x = 400, y = 110}
demon[2] = {x = 390, y = 80}
demon[3] = {x = 410, y = 30}
demon[4] = {x = 420, y = 20}
demon[5] = {x = 400, y = 200}
demon[6] = {x = 270, y = 260}

--this is for our creature movement
--prevents the same random numbers on each program run
math.randomseed(os.time() )

--x=width y=height
-- REMINDER ^^^^

-- the main loop
while true do
pad = Controls.read()
screen:blit (0, 0, level1)

--lets print some things to the screen shall we
screenrint(0, 0, "Alanan",red)
screenrint(0, 5, health, red)
screenrint(0, 10, armor, green)
screenrint(0, 15, ammo, green)

--lets make him move around
screen:blit(Player[1].x,Player[1].y,splayer[direction])
if pad:left() and Player[1].x > 0 then
Player[1].x = Player[1].x - 3
direction = 1
end

if pad:right() and Player[1].x < screenwidth then
Player[1].x = Player[1].x + 3
direction = 2
end

if pad:up() and Player[1].y > 0 then
Player[1].y = Player[1].y - 3
direction = 3
end

if pad:down() and Player[1].y < screenheight then
Player[1].y = Player[1].y + 3
direction = 4
end

--we need our creature to move too
screen:blit(creature[1].x,creature[1].y,creature)
creaturemove = math.random(0,50)

--now we make him move side note// i set creature move to math.random because i dont want him
-- moving all the time or else he would reach the end of the screen way to fast.
if creaturemove == 5 then
creature[1].x = creature[1].x + 1
end

-- we have to blit are demons to the screen also

if demonal[1] == "true" then
screen:blit(demon[1].x,demon[1].y,demon)
end

if demonal[1] == "true" then
screen:blit(demon[2].x,demon[2].y,demon)
end

if demonal[1] == "true" then
screen:blit(demon[3].x,demon[3].y,demon)
end

if demonal[1] == "true" then
screen:blit(demon[4].x,demon[4].y,demon)
end

if demonal[1] == "true" then
screen:blit(demon[5].x,demon[5].y,demon)
end

if demonal[1] == "true" then
screen:blit(demon[6].x,demon[6].y,demon)
end

-- now we make them chase the creature
--we are only gonna make two demons attack the creature
-- the other four will guard the exit

--heres demon 1
if demon[1].x > creature[1].x then
demon[1].x = demon[1].x - 1
end

if demon[1].x < creature[1].x then
demon[1].x = demon[1].x + 1
end

if demon[1].y > creature[1].y then
demon[1].y = demon[1].y - 1
end

if demon[1].y < creature[1].y then
demon[1].y = demon[1].y + 1
end

--now demon 2
if demon[2].x > creature[1].x then
demon[2].x = demon[2].x - 1
end

if demon[2].x < creature[1].x then
demon[2].x = demon[2].x + 1
end

if demon[2].y > creature[1].y then
demon[2].y = demon[2].y - 1
end

if demon[2].y < creature[1].y then
demon[2].y = demon[2].y + 1
end


--lets get his gun firing and ammo is there for reload
if pad:r() and ammo == 1 then
screen:blit(Bullet[1].x,Bullet[1].y,bullet)
fire = "true"
ammo = ammo - 1
reload:start()
--what if hes out of ammo?
elseif ammo == 0 then
fire = "false"
end

--this makes his bullet he shoots go different ways depending on which way he faces
if fire = "true" and direction == 1 then
Bullet[1].x = Bullet[1].x + 2
end

if fire = "true" and direction == 2 then
Bullet[1].x = Bullet[1].x - 2
end

if fire = "true" and direction == 3 then
Bullet[1].y = Bullet[1].y - 2
end

if fire = "true" and direction == 4 then
Bullet[1].y = Bullet[1].y + 2
end

-- now hes gotta reload
if ammo == 0 and reload:time() == 10 then
ammo = ammo + 1
end

--now lets make our bullet touch the demons
if Bullet[1].x == demon[1].x and Bullet[1].y == demon[1].y then
demonal[1] = "false"
end

if Bullet[1].x == demon[2].x and Bullet[1].y == demon[2].y then
demonal[2] = "false"
end

if Bullet[1].x == demon[3].x and Bullet[1].y == demon[3].y then
demonal[3] = "false"
end

if Bullet[1].x == demon[4].x and Bullet[1].y == demon[4].y then
demonal[4] = "false"
end

if Bullet[1].x == demon[5].x and Bullet[1].y == demon[5].y then
demonal[5] = "false"
end

if Bullet[1].x == demon[6].x and Bullet[1].y == demon[6].y then
demonal[6] = "false"
end

--what happens when the demons touch our creature???
if demon[1].x == creature[1].x and demon[1].y == creature[1].y then
chp = chp - 2
end

if demon[2].x == creature[1].x and demon[2].y == creature[1].y then
chp = chp - 2
end

if demon[3].x == creature[1].x and demon[3].y == creature[1].y then
chp = chp - 2
end

if demon[4].x == creature[1].x and demon[4].y == creature[1].y then
chp = chp - 2
end

if demon[5].x == creature[1].x and demon[5].y == creature[1].y then
chp = chp - 2
end

if demon[6].x == creature[1].x and demon[6].y == creature[1].y then
chp = chp - 2
end

--now this is if our creature dies
if chp == 0 then
screenrint(200,100,"Your Guide is Dead and hope is lost!", red)
end

--what if u die?
if health == 0 the
screenrint(200,110,"You have fallen all hope of escape is lost and your creature has fled!",red)
end

--new area
if creature[1].x == screenwidth then
currentarea = currentarea + 1
end

if currentarea == 1 then

How do I make it so that when he reaches the end othe screen he enters a new area but i dont want to exit my main loop??!?!?!?!?!?

EDIT: used spoiler because code is very long.

[EminentJonFrost]

--the creatures table
creature = {}
creature[1] = { x = 10, y = 10 }

--what area are u in???
currentarea = 0

--the width and height of screen
screenwidth = 480
screenheight = 272

--new area
if creature[1].x >= screenwidth then
currentarea = currentarea + 1
creature[1].x = 10 -- sending this guy back to where he started off in the map, but it could be anywhere you want.
elseif creature[1].x <= screenwidth - 479 then
currentarea = currentarea - 1
end

-- if put "creature[1].x <= screenwidth - 479 " so it could change 
-- even if the player went the other way. 

if currentarea == 0 then
screen:blit(0, 0, area here)
elseif currentarea == -1 then
screen:blit(0, 0, another area here)
elseif currentarea == 1 then
screen:blit(0, 0, other area here)

also, you might want to put an if statement that'll prevent 'currentarea' from reaching values other than the ones you want.

[Savagefreak]

--the creatures table
creature = {}
creature[1] = { x = 10, y = 10 }
 
--what area are u in???
currentarea = 0
 
--the width and height of screen
screenwidth = 480
screenheight = 272
 
--new area
if creature[1].x >= screenwidth then
currentarea = currentarea + 1
creature[1].x = 10 -- sending this guy back to where he started off in the map, but it could be anywhere you want.
elseif creature[1].x <= screenwidth - 479 then
currentarea = currentarea - 1
end
 
-- if put "creature[1].x <= screenwidth - 479 " so it could change 
-- even if the player went the other way. 
 
if currentarea == 0 then
screen:blit(0, 0, area here)
elseif currentarea == -1 then
screen:blit(0, 0, another area here)
elseif currentarea == 1 then
screen:blit(0, 0, other shiznit here)

That should work ;)

[EminentJonFrost]

lol
savagefreak solved the problem GG.

[TacticalPenguin]

Are yu trying to make an engine where when you hit the edge of the screen you go to a new "area"? I've made a system for doing that and if you'd like you can take a look at it.

[gameo]

I need some help with my PPP game. (Ping Pong Powerups. It's my first, so...)

Controls for both players work, thanks to EminentJonFrost, and the loader have been fixed thanks to eldiablov.

Now i need ball movement. I have the sprite of the ball, or rather, the image.
So i need a little help on turning it into an object, and help how to make it move random, and collosion with the bat's.

Here is the script:

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

screen:print(136, 136, "Loading LUA Pong...", white)
screen.flip()

background = Image.load("Background.png")

bat11 = Image.load("Bat1.png")

bat21 = Image.load("Bat2.png")

bat1 = { x = 20, y = 100 }
bat2 = { x = 460, y = 100 }

screen.waitVblankStart(60)

while true do

screen:clear()
screen:blit(bat1.x, bat1.y, bat11, true)
screen:blit(bat2.x, bat2.y, bat21, true)

pad = Controls.read()

if pad:down() then
bat1.y = bat1.y +2
end

if pad:up() then
bat1.y = bat1.y -2
end

if pad:cross() then
bat2.y = bat2.y +2
end

if pad:triangle() then
bat2.y = bat2.y -2
end

if pad:start() then
break
end

screen:print(136, 136, "Welcome to the world of PPP.", white)
screen.waitVblankStart()
screen.flip()
end

Help will be greatly apprisiated. (<-- Wrong spelled?)

[GuitarGod1134]

Are yu trying to make an engine where when you hit the edge of the screen you go to a new "area"? I've made a system for doing that and if you'd like you can take a look at it.

sure thanks.

[EminentJonFrost]

I need some help with my PPP game. (Ping Pong Powerups. It's my first, so...)

Controls for both players work, thanks to EminentJonFrost, and the loader have been fixed thanks to eldiablov.

Now i need ball movement. I have the sprite of the ball, or rather, the image.
So i need a little help on turning it into an object, and help how to make it move random, and collosion with the bat's.

Here is the script:

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

screen:print(136, 136, "Loading LUA Pong...", white)
screen.flip()

background = Image.load("Background.png")

bat11 = Image.load("Bat1.png")

bat21 = Image.load("Bat2.png")

bat1 = { x = 20, y = 100 }
bat2 = { x = 460, y = 100 }

screen.waitVblankStart(60)

while true do

screen:clear()
screen:blit(bat1.x, bat1.y, bat11, true)
screen:blit(bat2.x, bat2.y, bat21, true)

pad = Controls.read()

if pad:down() then
bat1.y = bat1.y +2
end

if pad:up() then
bat1.y = bat1.y -2
end

if pad:cross() then
bat2.y = bat2.y +2
end

if pad:triangle() then
bat2.y = bat2.y -2
end

if pad:start() then
break
end

screen:print(136, 136, "Welcome to the world of PPP.", white)
screen.waitVblankStart()
screen.flip()
end

Help will be greatly apprisiated. (<-- Wrong spelled?)

making the ball into an object is actually fairly easy, its same as making the bat into an object, which you have already done.

since this is ping pong, we'll make the ball first appear in the middle of the screen.

ball = { x = 240, y = 146, image = Image.load("ball image") } -- this is the middle of the screen, but blitting an
-- image here will make the ball seem a little lower and to the right.
-- play with the numbers til you get what you want.

what that has done is: give the ball coordinates and an image (basically).
i cant really help you very much with random movement. i'm kinda working on that myself (i hope within a few weeks you'll all see why :) ). i could help with collision though.

if ball.x == bat.x and ball.y >= bat.y and ball.y < [bats image length] then
bounce away
end

this'll make it so that when the ball is at the same vertical point as the bat AND within the image's length (so its touching, which makes sense), it'll do whatever you code in place of "bounce away". also, you might want to do to the 'x' what i did to the 'y'. so that the ball collides on more than just the one point, unless your bat is a single pixel wide.
-= Double Post =-
quick question: what was the command to draw a rectangle? the psdevwiki site is down...

[TacticalPenguin]

screen.fillRect(x,y,w,h)
or
screen.drawLine(sx,sy,ex, ey) four times

[EminentJonFrost]

screen.fillRect(x,y,w,h)
or
screen.drawLine(sx,sy,ex, ey) four times

hmm...so there isnt an actual command for it..oh well. Thanks!:)

[TacticalPenguin]

Well screen.fillRect() is, but it fills in the rectangle/square as well.

[EminentJonFrost]

yea, i know, i just need to draw the border of a rectangle. kinda like a frame for a health bar. well, actually, it'll do. i'll just put another rectangle over it in the background's color. problem solved!

[gameo]

Error: index.lua 27: unexpected symbol near [

Press start to restart.

Hmm?

Here is the modified script:

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

screenrint(136, 136, "Loading LUA Pong...", white)
screen.flip()

background = Image.load("Background.pn g")

bat11 = Image.load("Bat1.png")

bat21 = Image.load("Bat2.png")

bat1 = { x = 20, y = 100 }
bat2 = { x = 460, y = 100 }

ball = { x = 240, y = 146, image = Image.load("Ball.png") }

screen.waitVblankStart(60 )

while true do

screen:clear()
screen:blit(bat1.x, bat1.y, bat11, true)
screen:blit(bat2.x, bat2.y, bat21, true)

pad = Controls.read()

if ball.x == bat.x and ball.y >= bat.y and ball.x < [16] then
bounce away
end

if pad:down() then
bat1.y = bat1.y +2
end

if pad:up() then
bat1.y = bat1.y -2
end

if pad:cross() then
bat2.y = bat2.y +2
end

if pad:triangle() then
bat2.y = bat2.y -2
end

if pad:start() then
break
end

screenrint(136, 136, "Welcome to the world of PPP.", white)
screen.waitVblankStart()
screen.flip()
end

[TacticalPenguin]

Yea for the border you'll have to draw each line. Also since thatd make it draw 4 lines every loop, id put it on a buffer along with the rest of your non-changing objects.

[EminentJonFrost]

Yea for the border you'll have to draw each line. Also since thatd make it draw 4 lines every loop, id put it on a buffer along with the rest of your non-changing objects.

wait, put it on a buffer? whats that?
-= Double Post =-

Error: index.lua 27: unexpected symbol near [

Press start to restart.

Hmm?

Here is the modified script:

remove the brackets. (i think thats what theyre called)

[TacticalPenguin]

Ok do this:

buffer = Image.createEmpty(480,272)

Then for ALL your images and text and stuff that is NEVER changed at all, always stays in the same place, always says the same thing, do this:

buffer:blit(x,y,img)
buffer:print(x,y,text,color)

etc until everything on the screen that never moves has been put onto the image "buffer"
Just treat buffer like screen and put stuff on it until you've got everything put on it, then do this:

while true do
blah
blah
blah
screen:blit(0,0,buffer)

That'll put EVERYTHING on the buffer onto the screen. That makes luaplayer blit 1 image rather than blit 5 images, print 4 bits of text, draw 3 lines, etc each loop. It'll make your code more efficient if used properly.

But remember, you still have to use screen:blit(x,y,img) for stuff that moves, like the main player or somethin.

[Grimfate126]

Ok do this:

buffer = Image.createEmpty(480,272)

Then for ALL your images and text and stuff that is NEVER changed at all, always stays in the same place, always says the same thing, do this:

buffer:blit(x,y,img)
buffer:print(x,y,text,color)

etc until everything on the screen that never moves has been put onto the image "buffer"
Just treat buffer like screen and put stuff on it until you've got everything put on it, then do this:

while true do
blah
blah
blah
screen:blit(0,0,buffer)

That'll put EVERYTHING on the buffer onto the screen. That makes luaplayer blit 1 image rather than blit 5 images, print 4 bits of text, draw 3 lines, etc each loop. It'll make your code more efficient if used properly.

But remember, you still have to use screen:blit(x,y,img) for stuff that moves, like the main player or somethin.

thats uself for stuff like healthbar, ammo, and maybe levels. although, be careful not to put too much stuff on it, cause itll make it even slower. (cause it has to reference something from outside the loop.)

[EminentJonFrost]

oh, ok. buffer is good for stills and leave the rest normal. all right. i'll be sure to use it when i can. my problem with that though is that anything thats not part of the background pic moves. and well, the background is just one pic, would it be faster to put it to the buffer even though i have alot of other stuff moving?

[the undead]

How do you compile lua into an EBOOT, ive been searching every were for that tut.....if somebody could point me to the right direction i would be very thankfull.

[myschoo]

ok wait, i will give it to you

ok here it is:

http://www.mediafire.com/?8mwzrgg0dvg

it includes README.txt so u know what to do with it ;)

[the undead]

ok wait, i will give it to you

ok here it is:

http://www.mediafire.com/?8mwzrgg0dvg

it includes README.txt so u know what to do with it ;)

ok thanks.....my next game will be an eboot so people wont have to screw with that stupid luaplayer
-= Double Post =-
I downloaded it but.....how do you edit it?