Lua Programming Help Thread

[eldiablov]

if you want your script to stop and show you the error instead of shutting off setup your cmd file like this
luaplayer test.lua
pause



save it like this and it will pause whenever there is an error
that was for savagefreak

[emericaska8r]

God... now i finnaly got the ball to work with collosion in my ping pong game, thanks to Guitargod..

BUT! (Damm, there's always a but) At the start of the game, the ball is just blitted, and signed as an object, but i need it to move when the game starts!

(Yeah, i know nothing... *sniff*) So what should i write before the game loop, and what do i have to write?

I think my grammer is pretty wrong in this post. Oh well.

you need to already have directions set, so that at the start it will go these directions. then if you do have that, in your code you need:

if direction == "up" then
   bally = bally - 2
end
if direction2 == "right" then
   ballx = ballx + 2
end

ect.

[HeaD_ShOt]

how do i fix an error where it says table index is nil?

[eldiablov]

Post your script and im sure you'll get alot more response

[Anti-QuickJay]

Yea, We ned to see your sripct, It will make our job more easier

[TacticalPenguin]

you need to already have directions set, so that at the start it will go these directions. then if you do have that, in your code you need:

if direction == "up" then
   bally = bally - 2
end
if direction2 == "right" then
   ballx = ballx + 2
end

ect.

Would people PLEASE stop repeating things that have already been said?

[zmathue]

hay I got two questions

1. How do I print a ttf font to screen
   I written this code
   

   blue = Color.new(0,51,102)
   font = Font.load("font.ttf")
   
   while true do
   screen:clear()
   screen:fontPrint(Font, 0, 0,"ScoreHigh",blue)
   
   screen:waitVblankStart()
   screen:flip()
   end

   but all it does is clear the screen.
   
   
2. And can someone tell me where i can find a tut on how to assign a table to a image.

[TacticalPenguin]

Assigning a table to an image? Why not assign an image inside a table, like

table = { img1 = Image.load("img1.png"), img2 = Image.load("img2.png") }
while true do
screen:clear()
screen:blit(0,0,table.img 1)
screen:blit(200,200,table .img3)
screen.waitVblankStart()
screen.flip()
end

[zmathue]

lol i'm sorry i wasn't clear i meant like in shines snake game and many other games how they have diff. map pieces in one image

[TacticalPenguin]

Ah.

screen:blit(x, y, sourceimg, [sourcex, sourcey, width, height])

[gameo]

Would people PLEASE stop repeating things that have already been said?

It's okey Tactical, because i still dont get a f*** damm thing about it.

I guess you both explained well, but i just can't figure this (=_=) out!

Oh well, here is how it looks now, and it works without errors:

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 }

ball2 = Image.load("Ball.png")

screen.waitVblankStart(60 )

--assigning this to make the ball move HAHAHAHA that was funny anyways.
ballmoving = nil

while true do

screen:clear()
screen:blit(bat1.x, bat1.y, bat11, true)
screen:blit(bat2.x, bat2.y, bat21, true)
screen:blit(ball.x, ball.y, ball2, true)

pad = Controls.read()

--theres collision for bat1 now for bat 2
if ball.x == bat1.x and ball.y >= bat1.y and ball.x < (16*64) then
ballmoving = "true"
end

--theres paddle 2's collision
if ball.x == bat2.x and ball.y >= bat2.y and ball.x < (16*64) then
ballmoving = "false"
end

if ballmoving == "true" then
ball.x = ball.x + 2
end

if ballmoving == "false" then
ball.x = ball.x - 2
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

[GuitarGod1134]

hay I got two questions

1. How do I print a ttf font to screen
   I written this code
   

   blue = Color.new(0,51,102)
   font = Font.load("font.ttf")
   
   while true do
   screen:clear()
   screen:fontPrint(Font, 0, 0,"ScoreHigh",blue)
   
   screen:waitVblankStart()
   screen:flip()
   end

   but all it does is clear the screen.
   
   
2. And can someone tell me where i can find a tut on how to assign a table to a image.

Ok well lua player is case sensitive. And you assigned the font to a variable called "font" yet your trying to call it with the word "Font". Im pretty sure they have to be exactly the same so change it to

blue = Color.new(0,51,102)
font = Font.load("font.ttf")

while true do
screen:clear()
screen:fontPrint(font, 0, 0,"ScoreHigh",blue)

screen:waitVblankStart()
screen:flip()
end

[TacticalPenguin]

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

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

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

bat1 = { x = 20, y = 100, img = Image.load("Bat1.png") }--Put the images in tables
bat2 = { x = 460, y = 100, img = Image.load("Bat2.png") }

ball = { x = 240, y = 146, img = Image.load("Ball.png"), mx = 1, my = 0 }--Put ball's image in it's table
--MX and MY are movemenyx and movementy. Start off mx at 1
screen.waitVblankStart(60)


--Byebyeballmoving

while true do

screen:clear()

pad = Controls.read()

--theres collision for bat1 now for bat 2
if ball.x == bat1.x and ball.y >= bat1.y and ball.x < (16*64) then
ball.mx = -ball.mx
end

--theres paddle 2's collision
if ball.x == bat2.x and ball.y >= bat2.y and ball.x < (16*64) then
ball.mx = -ball.mx --That should make it opposite of ball.mx, making it change directions. 
end

--with ballmoving you had the idea but you need more

ball.x = ball.x + ball.mx --This makes the ball move to the right when ball.mx is positive, to the left when its negative.

--Then you can add some stuff dealing with my later. For making it move up//down, do something like
--ball.y = ball.y-ball.my

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

--blit images at the end, it sometimes can improve efficiency I think
screen:blit(bat1.x, bat1.y, bat11, true)
screen:blit(bat2.x, bat2.y, bat21, true)
screen:blit(ball.x, ball.y, ball2, true)

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

[zmathue]

i had the right case but i changed it when i posted

[Anti-QuickJay]

error: font.lua:5: attempt to index global 'Font' <a nil value>

What does this mean?

[Glynnder]

it means you haven't said what font is before

[TacticalPenguin]

It means in the file font.lua on line 5 you call the undefined variable "Font"

[Anti-QuickJay]

So, How will i fix it?

[eldiablov]

Can someone give me a good example of getting the enemy to chase player ?

[TacticalPenguin]

Theres a good tut over at evilmana.com for it

[eldiablov]

i followed that one but all i got was <eof> expected near end and got very confused.

[TacticalPenguin]

Well then learn from it and write your own. You arent limited to snippets people hand you.

[EminentJonFrost]

i followed that one but all i got was <eof> expected near end and got very confused.

i'm guessing you probrably just copied and pasted (or typed) the code as it was to your code without making changes to your original and that thats why youre starting to have errors.

[eldiablov]

Maybe. but i was going to change it to something more suitable once i got it to work. It's ok now i got it to work. rewriting as we speak. Whats the command for disabling controls ?

[TacticalPenguin]

You mean for making no buttons do anything?

[eldiablov]

yeah i want it so when my player meets my enemy that a screen comes up with gameover and credits but i want controls disabled so i that screen will stay there

[TacticalPenguin]

screen.waitVblankStart(nu mberofsecondsyouwantittos ittheretimes60)

[Highsight]

I am trying to make an LUA Side Scroller, and I am having a horrible time thinking of how to make the screen scroll when the character gets close enough. I am doing this tile based, with a text file that creates 2d int arrays for the tile number. How would I be able to scroll the map?

[dracule]

is there a way to get a different texture on each side of the 3d object? Ive been experiementing but cant really find anything to let me do it, I think there is but I cant find anything. If anyone knows please help me.. (by the way, if you do help me please make it relative to the 3d cube that came with luaplayer). :)

i kind of had to scrap my other project because i tried a code scrambling but i forgot to back up my data so i dont know what variables are what... but i guess it would prevent some code theft.

[EminentJonFrost]

who here knows how to use the analog stick?