Lua Programming Help Thread

[MagicianFB]

Links: PSProgramming, Lua Discussion Thread, PSP Dev Forum Rules, Lua Examples

USE CODE TAGS!

Hey guys, since there are so many lua help threads popping up, we should just have one main one, so just post whatever lua questions you have in here.

I'll start off

when I use System.listDirectory() all I get are table values such as

table: 0x89ad10

Does anyone know how this function works?

Edit:

Guys, www.luaplayer.org. Click the wiki, every single Lua Player function is documented there. Having trouble with your code? http://lua-users.org/wiki/TutorialDirectory. It documents the lua scripting language.
After you go through that, I can say that at least 90% of the questions asked can be avoided. Less questions = less spam and better coders. So please, read it.

[TeamOverload]

i need help getting the battery % remaining to load and actually display. also is it possible to write to the flash using lua?

[whitehawk]

This is a good. Idea You should sticky this (if you can, I know your a NDS mod ).

If you can't, another mod should :icon_wink

[MagicianFB]

Originally Posted by whitehawk

This is a good. Idea You should sticky this (if you can, I know your a NDS mod ).

If you can't, another mod should :icon_wink

I wonder if I'm allowed to :think:

Originally Posted by TeamOverload

i need help getting the battery % remaining to load and actually display. also is it possible to write to the flash using lua?

This will make it display the battery life percent until X is pressed:

print(tostring(System.powerGetBatteryLifePercent()) .. "%")
screen:flip()

while true do
	pad = Controls.read()
	if pad:cross() then
		break
	end
end

Ignore the spaces in strange places, it's a forum glitch

[EstaCompton]

This is a great idea! If anyone can help me with my problem, refer to the Rotating Image thread and you can reply here. This should keep the threads looking a little cleaner.

[JOVENASO]

uhmm need some help how to make a pad that make two buttons make one function
pad = Controls.read()
if pad:cross() then
break
end

thanks

[MagicianFB]

Originally Posted by JOVENASO

uhmm need some help how to make a pad that make two buttons make one function
pad = Controls.read()
if pad:cross() then
break
end

thanks

what?

[JOVENASO]

Originally Posted by MagicianFB

what?

ok i ask if is posible to make 2 buttons make one fuction ..... example press cross and square at the same time and that will make a break or do something ... like on umd loadder

[TeamOverload]

i am still wondering if u can write to the flash using lua

[MagicianFB]

Originally Posted by TeamOverload

i am still wondering if u can write to the flash using lua

I don't know. You might be able to access the flash, but I'm not sure how to create new files.

[TeamOverload]

ya, but could you overwrite current files?

[Twenty 2]

Does anyone know how to make a sidescroller? do you need one giant image and use code to make it scroll once a unit enters a area. Does anyone have the code to do this or a example game in lua? Help would be apreciated.

22

[Jeremy1026]

Originally Posted by TeamOverload

i am still wondering if u can write to the flash using lua

not now...atleast, probably not now, since lua is still very basic

[whitehawk]

Originally Posted by JOVENASO

ok i ask if is posible to make 2 buttons make one fuction ..... example press cross and square at the same time and that will make a break or do something ... like on umd loadder

pad = Controls.read()

if pad:square() and pad:circle() then
break
end

[TeamOverload]

Originally Posted by Jeremy1026

not now...atleast, probably not now, since lua is still very basic

ok, thanks. this is a great thread, you get answers very quickly. this should be stickied

[MagicianFB]

Originally Posted by TeamOverload

ya, but could you overwrite current files?

I really couldn't say...

Originally Posted by whitehawk

pad = Controls.read()

if pad:square() and pad:circle() then
break
end

Would that work?
both pad and Controls.read() only can have one value, so wouldn't this work better?

while true do

	pad1 = Controls.read()
	pad2 = Controls.read()

	if pad1:square() then
		if pad2:circle() then
			break
		end
	end
end

[EstaCompton]

No one's helping me

[Bilo]

Right..

I've got two folders

psp/game/nameofgame/
nameofgame%/

why is it that if I change either of the names of these folders my script stops working?

Or.. am I just being stupid?

[Virtue]

I am trying to make a coin flipping program, you press X and it will display an message, heads, or with tails. Here is as far as the display part goes.

pad = Controls.read()

screen:print(120, 15, "Welcome to my coin toss game!", blue)
screen:print(60, 190, "Press X to Flip Coin!", yellow)
screen.flip()

if pad:cross() and (math.random(1,2) < 2) then
while true do
screen:clear()
screen:blit(0, 0, bg, false)
screen:print(120, 15, "Welcome to my coin toss game!", blue)
screen:print(160, 30, "Created By Jesse", red)
screen:print(60, 190, "Press X to Flip Coin!", yellow)
screen.flip()
screen:print(60, 160, "Coin Flipped! Heads!", yellow)
while true do
screen.flip()


elseif pad:cross() and (math.random(1,2) > 1) then
screen:clear()
screen:blit(0, 0, bg, false)
screen:print(120, 15, "Welcome to my coin toss game!", blue)
screen:print(160, 30, "Created By Jesse", red)
screen:print(60, 190, "Press X to Flip Coin!", yellow)
screen.flip()
screen:print(60,160, "Coin Flipped! Tails!", yellow)
screen.flip()
end[

Something is wrong with the part under the if pad.

[Bilo]

Shouldnt your if's be

"if (pad:cross()) and (math.random(1,2) < 2) then"

both statements either side of the 'and' have to be in ( )'s

..... ?

[cools]

this is probably n00bish but how do you load small images in certain spots?

Ive tried this:
Random Image = Image.load(100, 200, "Random Image.png")

but it wont load anything ( no that is not my real script just an example. I cant get anything to load it just says press start to restart. Every now and then text that is supposed to be displayed ends up showing in the menu. PLZ Help!

[MagicianFB]

Originally Posted by cools

this is probably n00bish but how do you load small images in certain spots?

Ive tried this:
Random Image = Image.load(100, 200, "Random Image.png")

but it wont load anything ( no that is not my real script just an example. I cant get anything to load it just says press start to restart. Every now and then text that is supposed to be displayed ends up showing in the menu. PLZ Help!

You have to blit the image then update the screen by using "screen:flip()"

image = Image.load("image.png")
screen:blit(=100, 200, image)

screen:flip()

Originally Posted by EstaCompton

No one's helping me

No one's helped me either
Noone knows how to do what your asking.

[MagicianFB]

Originally Posted by Virtue

I am trying to make a coin flipping program, you press X and it will display an message, heads, or with tails. Here is as far as the display part goes.

It should look like this:

bg = Image.load("bg.png")

red = Color.new(255, 0, 0)
blue = Color.new(0, 0, 255)
yellow = Color.new(255, 255, 0)


while true do
	pad = Controls.read()

	screen:print(120, 15, "Welcome to my coin toss game!", blue)
	screen:print(60, 190, "Press X to Flip Coin!", yellow)
	screen.flip()

	if pad:cross() then
		side = math.random(2)
		if side==1
			screen:clear()
			screen:blit(0, 0, bg, false)
			screen:print(120, 15, "Welcome to my coin toss game!", blue)
			screen:print(160, 30, "Created By Jesse", red)
			screen:print(60, 190, "Press X to Flip Coin!", yellow)
			screen:print(60, 160, "Coin Flipped! Heads!", yellow)
			screen.flip()
		elseif side==2
			screen:clear()
			screen:blit(0, 0, bg, false)
			screen:print(120, 15, "Welcome to my coin toss game!", blue)
			screen:print(160, 30, "Created By Jesse", red)
			screen:print(60, 190, "Press X to Flip Coin!", yellow)
			screen:print(60,160, "Coin Flipped! Tails!", yellow)
			screen.flip()
		end
	end

[Lancer]

pad = Controls.read()

if pad:up() then
	menupos = menupos - 1
	if menupos == 0 then
		menupos = 3
	end
end

if pad:down() then
	menupos = menupos + 1
	if menupos == 4 then
		menupos = 1
	end
end

1. If I don't just ever so lightly tap the d-pad, the cursor will go down at least 4-5 spaces in a single normal press of the button. How can I make it so the cursor will only move one space for every button press.

Edit: I tried Vblanks, but they didn't work at all.

screen:print(0,40,"###",rgb)
screen:print(0,50,"###",rgb)
screen:print(0,60,"###",rgb)

2. How do I use drawrect? >_>

3. It would be really cool if someone could show me some tips to optimize my code.

Thanks in advance.

[EstaCompton]

True, true. Maybe I'll do something easier....

[cools]

Thanks !

[TeamOverload]

does anyone have a list of functions for lua??

[c5cha7]

Oh YES!!!
I really need help (I never knew there was a thread like this)
How can i make a main menu and make a topdown view person walk.
I really wanna make my DBZ Charecter walk on the screen but he stay's still

Anyhelp would be highley appreciated.

[MagicianFB]

Originally Posted by Lancer

pad = Controls.read()

if pad:up() then
	menupos = menupos - 1
	if menupos == 0 then
		menupos = 3
	end
end

if pad:down() then
	menupos = menupos + 1
	if menupos == 4 then
		menupos = 1
	end
end

1. If I don't just ever so lightly tap the d-pad, the cursor will go down at least 4-5 spaces in a single normal press of the button. How can I make it so the cursor will only move one space for every button press.

Edit: I tried Vblanks, but they didn't work at all.

screen:print(0,40,"###",rgb)
screen:print(0,50,"###",rgb)
screen:print(0,60,"###",rgb)

2. How do I use drawrect? >_>

3. It would be really cool if someone could show me some tips to optimize my code.

Thanks in advance.

There is no drawRect function in lua so you have to make your own.

function drawRect(where, x, y, width, height, color)
	where:drawLine(x, y, x+width, y, color)
	where:drawLine(x+width, y, x+width, y+height, color)
	where:drawLine(x+width, y+height, x, y+height, color)
	where:drawLine(x, y+height, x, y, color)
end

-- Use it like this

drawRect(screen, 20, 20, 40, 20, blue)

Also vblank should work

Just put this at the start of your while loop:

screen.waitVblankStart(5)

[MagicianFB]

Originally Posted by TeamOverload

does anyone have a list of functions for lua??

http://www.lua.org/pil/index.html#P3
http://luaplayer.org/functions.txt