Lua Programming Help Thread

[Twenty 2]

How are we suppost to help you if we have no idea what you are trying to do?

[SG57]

You know, an arrow arcs when shot, a bullet arcs but slowly, stuff like that

what im asking is so that when i shoot my bullet or arrow, it arcs about 3 pixels and rotates a lil every 1/4 a second

Do you know what I mena yet? I have an idea but i doubt itll work

[aldebaran]

Someone know which is the command to create a new file (text file) where i can put a table?

[Sir Crx]

still no answer for my question?

[will1234]

i solved my problem now

[c5cha7]

Okay hi everyone.
I am making a new game...
This is gonna be my first side scroller.
Now some of my code was from my chao garden
so it might not be all Fancy and neat..
Anyway i need to know how to make my Player
Jump on a barrier or image.
Here's alittle bit of my code. \\//

sprite = {}

sprite[1] = Image.load("sprite.png")
sprite[2] = Image.load("sprite2.png")
sprite[3] = Image.load("sprite3.png")
sprite[4] = Image.load("sprite2-2.png")
sprite[5] = Image.load("sprite3-3.png")
sprite[6] = Image.load("sprite-1.png")
sprite[7] = Image.load("sprite4.png")
sprite[8] = Image.load("sprite4-4.png")
Spriteimg=sprite[1]

anim = 1
animTimer = 0
LastDirection = sprite[1]

function duck()
if LastDirection==sprite[1] then Spriteimg=sprite[7]
elseif LastDirection==sprite[6] then Spriteimg=sprite[8] end
end



function walkRight()
LastDirection=sprite[1]
animTimer=animTimer+1
   if animTimer>=1 and animTimer<=4 then Spriteimg=sprite[2]
   elseif animTimer>=5 and animTimer<=8 then Spriteimg=sprite[3]
   end
   if animTimer>=9 then animTimer=0 end
end

function walkLeft()
LastDirection=sprite[6]
animTimer=animTimer+1
   if animTimer>=1 and animTimer<=4 then Spriteimg=sprite[4]
   elseif animTimer>=5 and animTimer<=8 then Spriteimg=sprite[5]
   end
   if animTimer>=9 then animTimer=0 end
end


while true do
   screen:blit(0, 0, Background)
   pad = Controls.read()
   if pad:right() then walkRight() x=x+3 Spriteimg=Spriteimg
   elseif pad:left() then walkLeft() x=x-3 Spriteimg=Spriteimg
   elseif pad:up() then walkLeft() y=y+3 Spriteimg=Spriteimg
   elseif pad:down() then walkLeft() y=y-3 Spriteimg=Spriteimg
   else Spriteimg=LastDirection
   end

This isnt all my code but it'a what i have found that help's me.
If anyone's intrested in making GFX or helping for my new project then
please PM me as it's Invite's ONLY.

Thank's :icon_bigg

P.S
I Also have a jumping problem lol.

[XteticX]

Someone know which is the command to create a new file (text file) where i can put a table?

There's not really a function to create a file, you just tell lua what the file name is and then make it write on it. Here's an example:

SaveFile="save.txt"
function saveTable()
   file=io.open(SaveFile,"w")
   if file then
      file:write("MyTable={")
      for index, value in Table do--TABLE WOULD BE THE TABLE'S NAME!
        file:write(value..",")--THE VALUE ALONE
      end
      file:write("}")
      file:close()
   end
end

You could prob replace SaveFile for the file's name in

file=io.open(SaveFile,"w")

Also, I only made it write the index's value in that example, but you can make it write the index too that's all up to you.

So just expirement. :)

[XteticX]

You know, an arrow arcs when shot, a bullet arcs but slowly, stuff like that

what im asking is so that when i shoot my bullet or arrow, it arcs about 3 pixels and rotates a lil every 1/4 a second

Do you know what I mena yet? I have an idea but i doubt itll work

I think I understand what you mean by ARCing down. Make the bullet fall on the ground after a while right? Anyway, here's a cheap way you could do it.

I'm assuming the bullet's Y is "bulletY", so here goes.

function bulletGravity()
local CurrentY=bulletY
local time=0
time=time+1
 if time>=50 then --WHEN THE BULLET START'S DROPPING DOWN
   for y=CurrentY,272 do --FROM TRAJECTORY TO BOTTOM OF SCREEN
     bulletY=bulletY-0.5
   end
 end
end

That would be like I said a cheap trick. But then again, I never saw your code and this might not be the best idea. On top of that, it might freeze the game and make the bullet stop going forward if its used as a single function. Your best bet would be to create one big function and have the bullet's velocity ,arcing effect and what not into one function.

Anyway good luck.

(sorry for the double post.)

[aldebaran]

Thanks! I'll try it ASAP

[c5cha7]

Please could someone help?
Sorry on such short notice but i have a small problem....
Well i have made my Sprite's and character's and done all the code for my game BUT, Know my character cant jump properly?
Oh and how can i make barrier's?
Like on mario when you can jump on the ledge above.
I just really need to know how to make barrier's so my player can
hit thing's and stand on them lol.

Thank's in return.

[monster356]

Please could someone help?
Sorry on such short notice but i have a small problem....
Well i have made my Sprite's and character's and done all the code for my game BUT, Know my character cant jump properly?
Oh and how can i make barrier's?
Like on mario when you can jump on the ledge above.
I just really need to know how to make barrier's so my player can
hit thing's and stand on them lol.

Thank's in return.

I would like to know the same

[SG57]

I think I understand what you mean by ARCing down. Make the bullet fall on the ground after a while right? Anyway, here's a cheap way you could do it.

I'm assuming the bullet's Y is "bulletY", so here goes.

function bulletGravity()
local CurrentY=bulletY
local time=0
time=time+1
 if time>=50 then --WHEN THE BULLET START'S DROPPING DOWN
   for y=CurrentY,272 do --FROM TRAJECTORY TO BOTTOM OF SCREEN
     bulletY=bulletY-0.5
   end
 end
end

That would be like I said a cheap trick. But then again, I never saw your code and this might not be the best idea. On top of that, it might freeze the game and make the bullet stop going forward if its used as a single function. Your best bet would be to create one big function and have the bullet's velocity ,arcing effect and what not into one function.

Anyway good luck.

(sorry for the double post.)

Thanks and you were right on thats what i wanted!

anyway, i have just figured out the resizer function and it works! its sweet!

Well, now all ineed is to know how to make a sidescroll type of thing, but its not really a sidescrolling thing, its more ofa one picture backround flying horizontly past the screen over and over again so can someone please help me with this?

[Twenty 2]

Thats called sidescrolling ....

[monster356]

Umm, Help SG57 and I make a sidescrolling BG, because i need the same

[SG57]

somebody answered me awhile back buttt...

they just said something about a bgXy + 479 and stuff like that heres the post:

"I have a number, bgX, that is default 0
now think about this, i said that if its < 0, then blit the image at bgX and bgX+479
if its after 0, then make it bgX-480
if its less than -(480-480) then make it -480

if you push left or right, make bgX + or -"

can someone explain this alittle better or give me an example of a sidescrolling game?

also, like in the lua windows shell, how do you make it so if you go over a thing, in my case its a menu, it lights up a bit or if you push X on that certain thing/pixel, it does my own file, i know how to do the:

dofile("script.lua)

type thing, anyone can help? thanks alot if yu can!

[c5cha7]

Hmm.
I Would actually like to know how to make a sidescrolling background.
That would be a nice addition to my game lol.
But barrier's would still be nice :icon_bigg

[c5cha7]

also, like in the lua windows shell, how do you make it so if you go over a thing, in my case its a menu, it lights up a bit or if you push X on that certain thing/pixel, it does my own file, i know how to do the:

dofile("script.lua)

type thing, anyone can help? thanks alot if yu can!

Hmm..
I Could help you with that
Here \/

 
screen:blit(18, 18, image)
	if x0 < 50 then
		if x0 > 15 then
			if y0 < 60 then
				if y0 > 15 then
				screen:blit(18, 18, highlighted)
		                          if pad:cross() then
				dofile("script.lua)
				end
			end
		end
	end

Or something like that.
If it's not a mouse then change these \/

	if x0 < 50 then
		if x0 > 15 then
			if y0 < 60 then
				if y0 > 15 then

That's all i can do for know lol.

[sofa king dumb]

would putting numbers in the () for "if pad:start(###) then" mean if start is held for ### time then, or how eles could this be done?

[XteticX]

would putting numbers in the () for "if pad:start(###) then" mean if start is held for ### time then, or how eles could this be done?

I dont think pad:start() can hold any arguments. Just create a simple loop. Someting like:

while pad:start() do
time=time+1
  if time>=50 then
    time=0
    "execute and action here"
  end
end

I never tested if "while pad:start() do" would work. It should. lol :icon_bigg

[SG57]

THAN

Hmm..
I Could help you with that
Here \/

 
screen:blit(18, 18, image)
	if x0 < 50 then
		if x0 > 15 then
			if y0 < 60 then
				if y0 > 15 then
				screen:blit(18, 18, highlighted)
		                          if pad:cross() then
				dofile("script.lua)
				end
			end
		end
	end

That's all i can do for know lol.

THANKS, and ya its with a mouse and i just tried it and it said line 26: trying to compare nil value, so that means at the start of the if statements is where the error is so

, now if iwanted to changed where the cursor would go over, say pixel (232, 131) but not that specific pixel, but its a rectangle area, so the area between pixels (232, 142), (249, 142) ,(232, 131) and (249, 131), then what would i do? and its with a cursor.

EDIT

o forgot one major question for my game...how do i rotate an image not 90* like in the function in the developers dungeon, but say like 10* if i press up and down 10*... thank you alot if you can help at all

[monster356]

Hmm.
I Would actually like to know how to make a sidescrolling background.
That would be a nice addition to my game lol.
But barrier's would still be nice :icon_bigg

I got a sidscroller from www.lumo.at.tt and fixed it up so it works better than it initially did

and i believe barriers would have to have some collision detection, to know if you hit it

[SG57]

how to make the backround go faster than that would help a bunch if so,

lastly for about a month or 2 casue im at a friends house so im posting all these questions os i can view the answers on my fired up browser,

i have my menu made and stuff but i cant get the script.lua to load if i go over a certain pixel with my cursor, so heres my code (also, i made it so when i click X, it makes a mouse click, but now i have to hold the X down to move the cursor and it makes too many clicks so ill post that code with it)

System.usbDiskModeActivate()
level = Image.load("explosive/MAIN.PNG")
click = Sound.load("sounds/click.wav")
white = Color.new(255, 255, 255)
green = Color.new(0, 255, 0)
orange = Color.new(255, 128, 0)
teal = Color.new(64, 128, 128)
blue = Color.new(0, 0, 255)
red = Color.new(255, 0, 0)
a = Color.new(0, 0, 0)
lightgreen = Color.new(0, 180, 0)
lightyellow = Color.new(165, 157, 67)
brown = Color.new(128, 64, 0)
arrow = Image.load("explosive/CURSOR.PNG")
arrowX=240
arrowY=136
speed = 5
CurrentArrow = arrow
while true do
 screen:blit(0, 0, level, 0, 0, level:width(), level:height(), false) 
 if x0 < 50 then
  if x0 > 15 then
   if y0 < 60 then
	if y0 > 15 then
	screen:blit(18, 18, highlighted)
		if pad:cross() then
	dofile(./"script.lua")
	end
   end
  end
 end
 screen.waitVblankStart()
 pad=Controls.read()
 if pad:analogX() < -30 then
 arrowX = arrowX - speed
 end
 if pad:analogX() > 30 then
 arrowX = arrowX + speed
 end
 if pad:analogY() < -30 then
 arrowY = arrowY - speed
 end
 if pad:analogY() > 30 then
 arrowY = arrowY + speed
 end
 screen:fillRect(0, 0, 0, 0, a)
 screen:blit(arrowX, arrowY, CurrentArrow)
  if pad:cross() then
   click:play()
 screen.waitVblankStart()
 screen.flip()
end
end

here it is guyz, need some help with it too,

i think i can remove the click sound from the cursor and make it so if i click X anyway, it does the sound and that fixes that,

i think i might try moving all the things uner my backround picture to my cursor to see if that fixes anything

unless soemone has found a way to get this to work?

[CtrlAltDeleteDie]

Hi. Im working on a lua game. If i move an object to one side of the screen, how do i make it stop? I have this code, but the object cant move after if hits the side

blockposX = 152
blockposY = 20

while true do
       screen:blit(0, 0, field)
screen:blit(blockposX, blockposY, block3)

       screen.waitVblankStart()
       screen.flip()

       if blockposX >= 427 then
	 blockposX = 452
       end

       pad = Controls.read()

       if pad:left() then
	 blockposX = blockposX - 25
end

       if pad:right() then
	 blockposX = blockposX + 25
end

SOLVED!

[SG57]

blockposX = 152
blockposY = 20
 
while true do
screen:blit(0, 0, field)
screen:blit(blockposX, blockposY, block3)
 
screen.waitVblankStart()
screen.flip()
 
if blockposX >= 427 then
	 blockposX = 452
end
 
pad = Controls.read()
 
if pad:left() then
	 blockposX = blockposX - 25
end
 
if pad:right() then
	 blockposX = blockposX + 25
end

SOLVED!

Hey howd you fix yours? is that the fixed one or what casue that looks right to me

[monster356]

Hey howd you fix yours? is that the fixed one or what casue that looks right to me

not really, i would say that he moved the:
screen.waitVblankStart()
screen.flip()
to the end, so i believe if that happened it would work!

SG57, what exactly is your prob?

[SG57]

my menu wont work, can sum 1 get it to work? its posted a bit up

[WraithLeader]

error: index.lua:1: '=' expected near 'e'
Error: No script file found.

Press start to restart

I have been trying to learn Lua from the tutorial, but I keep getting this error when I try to implement the example coding for the second lesson, but I keep getting this error. I am using LuaPlayer .14 and selecting using the Lowser function, setting the code, data files, pictures, ect. into an application folder and renaming the lua script to "index.lua". I am using Mac OS X 10.4 and TextEdit to try and code. i am using a plain text document, but the application makes me encode in codex like "Western (Mac OS)" or "Unicode (UTF-16)" or "Western (Windows Latin 1)" and other such encodings.

If anyone can help me or any one who uses a Mac enlighten me if I am doing things incorrectly, I would really appreciate the help.

[SG57]

post ur code... can any 1 help me with mine?

[WraithLeader]

Unfortunately, the automatic forum respnse is giving me this error when trying to post the code:

1. You have included too many images in your signature or in your previous post. Please go back and correct the problem and then continue again.

Images include use of smilies, the vB code [img] tag and HTML <img> tags. The use of these is all subject to them being enabled by the administrator.

The code can alternatively be found in this thread PSP Programming Tutorials in Lua - Lesson One, Hello World in the second tutorial (second post), under the line "NOW! We are done! Now you can really hug yourself, because your PSP Application coded in LUA, is DONE!


Here is what your code should look like:"

[monster356]

I have been trying to learn Lua from the tutorial, but I keep getting this error when I try to implement the example coding for the second lesson, but I keep getting this error. I am using LuaPlayer .14 and selecting using the Lowser function, setting the code, data files, pictures, ect. into an application folder and renaming the lua script to "index.lua". I am using Mac OS X 10.4 and TextEdit to try and code. i am using a plain text document, but the application makes me encode in codex like "Western (Mac OS)" or "Unicode (UTF-16)" or "Western (Windows Latin 1)" and other such encodings.

If anyone can help me or any one who uses a Mac enlighten me if I am doing things incorrectly, I would really appreciate the help.

When i was doing it i had a few errors, but i got it figured out, I can send my code to you