Lua Programming Help Thread

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Zitat von nUke_moose

sry for asking.....but this still doesnt help me that much, maybe ill explain what i want to do: basically, the first thing every beginner makes, after completing the tutorials, is a 2d sidescrolling game with simple animation. i know how to use all the other buttons, but the analog somehow wont work

so please be a little more detailed or just give me link, cuz im new to the szene and dont really know alot of good websites....

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I made a DDR clone. Without tuturials (as there were none at the time)

Anyway, stop asking for tutorials. Tutorials = making you a lua n00b. Learn yourself. You understand it better.
Controls:analogX() and Controls:analogY() returns a number between -127 and 128, note that they are OO, so you should pass a Controls object to it. (Im sure youve learned pad or whatever)

did ya try evilmana to see if they had stuff over analog? cause i checked and found it

Zitat:

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Zitat von nUke_moose

sry for asking.....but this still doesnt help me that much, maybe ill explain what i want to do: basically, the first thing every beginner makes, after completing the tutorials, is a 2d sidescrolling game with simple animation. i know how to use all the other buttons, but the analog somehow wont work

so please be a little more detailed or just give me link, cuz im new to the szene and dont really know alot of good websites....

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sample script:

Code:

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red = Color.new(255,0,0)
black = Color.new(0,0,0)
white = Color.new(255,255,255)

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

Player = { x = 100, y = 100, img = player }

function analogMove()

pad = Controls.read()

anaX = pad:analogX()
anaY = pad:analogY()

if anaX > 50 then
Player.x = Player.x + 5
end

if anaX < -50 then
Player.x = Player.x - 5
end

if anaY > 50 then
Player.y = Player.y + 5
end

if anaY < -50 then
Player.y = Player.y - 5
end
end

function walls()

if Player.x > 448 or Player.x < 0 then
Player.x = oldx
end

if Player.y < 0 or Player.y > 240 then
Player.y = oldy
end
end

while true do

oldx = Player.x
oldy = Player.y

screen:clear()

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

analogMove()
walls()

screen:print(5,5,"analogX: " .. anaX, white)
screen:print(5,15,"analogY: " .. anaY, white)

if pad:cross() then
break
end

screen.flip()
screen.waitVblankStart()
end

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thx for the replies, i know i should have found out about it by myself, so ill remember it better, but im beeing cut off the internet for a week, starting tomorrow, and i thought id ask before i get stuck... well, thx again

I always thought it was silly when the analog controls were used like digital ones in situations like that. By the way, I just searched this thread for "analog" and this was from one of the first results:

Code:

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pad =  Controls.read();
if math.abs(pad:analogX()) > 20 then
      x = x + pad:analogX() / 64;
end
if math.abs(pad:analogY()) > 20 then
      y = y + pad:analogY() / 64;
end
screen:print(x,y-5,"<|",w);
screen.waitVblankStart();
screen.flip()

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Notice that the more the analog stick is deflected, the larger the change in position.

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Zitat von LMelior

I always thought it was silly when the analog controls were used like digital ones in situations like that. By the way, I just searched this thread for "analog" and this was from one of the first results:

Code:

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pad =  Controls.read();
if math.abs(pad:analogX()) > 20 then
      x = x + pad:analogX() / 64;
end
if math.abs(pad:analogY()) > 20 then
      y = y + pad:analogY() / 64;
end
screen:print(x,y-5,"<|",w);
screen.waitVblankStart();
screen.flip()

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Notice that the more the analog stick is deflected, the larger the change in position.

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^^
thats the correct usage of the analog stick. if you just want to move something by a constant, why not use the d-pad?

hiii thereee its mee again,,, does any body know where to find Lua Player v0.20 Mod 3 binary files ??? i i can found is the source... and ive no idea of how to compile...

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Zitat von myschoo

sample script:

Code:

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red = Color.new(255,0,0)
black = Color.new(0,0,0)
white = Color.new(255,255,255)

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

Player = { x = 100, y = 100, img = player }

function analogMove()

pad = Controls.read()

anaX = pad:analogX()
anaY = pad:analogY()

if anaX > 50 then
Player.x = Player.x + 5
end

if anaX < -50 then
Player.x = Player.x - 5
end

if anaY > 50 then
Player.y = Player.y + 5
end

if anaY < -50 then
Player.y = Player.y - 5
end
end

function walls()

if Player.x > 448 or Player.x < 0 then
Player.x = oldx
end

if Player.y < 0 or Player.y > 240 then
Player.y = oldy
end
end

while true do

oldx = Player.x
oldy = Player.y

screen:clear()

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

analogMove()
walls()

screen:print(5,5,"analogX: " .. anaX, white)
screen:print(5,15,"analogY: " .. anaY, white)

if pad:cross() then
break
end

screen.flip()
screen.waitVblankStart()
end

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whats that for? game?

it can be for anything

Is there a way to insert a tab into a string (except using a few spaces) because "\tHello" prints OHello.

TIA

Yea but first you have to stop listening to fallout boy. Lua detects if you are and makes everything not work.

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Zitat von Fallout_Boy

Is there a way to insert a tab into a string (except using a few spaces) because "\tHello" prints OHello.

TIA

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There is no such set "tab". Lots of text editors insert 4 spaces for a tab, while notepad inserts 8. So just do a.. string.gsub(str,"\t", string.rep(" ",4))

hii there this is my foruth post i think, and see what i have four you guys, :P if you know 3dmax, or ascii 3d files (ASE) you you must try this tool i just made, its a tool to port 3dmax models to lua trought ASE format. all you have to do is to expot your max to ase then use my tool and you will have the triangle array to use in gu.
Download Ahrimanes ASE2LUA v0.1
it includes:
some ase models
1 max model to test 3dmx to ase then lua
ase2lua v0.1 by ahrimanes (me)
tutorial folder
and eboot folder(this is a test of the ship.max) basically luaplayer testhing ase2lua output.

well still left to port the u,v for maping, by now no textures suported, but you can start testing complexmodels on you programs. hope you like... stay tuned to futher releases.....
pleaaaseee leave your comentesss.
edit: haaaa almost forgot, this runs under windows and you must have installed ms excel.

How do I inject letters into a string? For example, if my string was "abdef", how would i make it say "abcdef"? Also, how do you read just part of a string, say, the first ten characters? And lastly, how do you find the number of characters in a string? Thanks for any help.

Just a screen from the mandelbrot-like program i'm making.
http://img242.imageshack.us/img242/9...enshot8ap6.png

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Zitat von romulator

How do I inject letters into a string? For example, if my string was "abdef", how would i make it say "abcdef"? Also, how do you read just part of a string, say, the first ten characters? And lastly, how do you find the number of characters in a string? Thanks for any help.

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str1 = str1 .. "t"
= string.sub(str1,1,10)
= string.len(str1)

Hey, thanks for that youresam. That clears up a lot of confusion. Could you please just elaborate on the second argument of the second function? I like to understand things fully before I use them. Thanks again!

EDIT: The first function adds text to the end of a string but how will I be able to inject it into the middle of the string as in my example?
EDIT2: Adding "\n" to the end of a string doesn't print a new line, it only prints the letter O in a black box. Whats up with that?

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EDIT: The first function adds text to the end of a string but how will I be able to inject it into the middle of the string as in my example?
EDIT2: Adding "\n" to the end of a string doesn't print a new line, it only prints the letter O in a black box. Whats up with that?

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im not shure if there is not a function to insert text but if its the case you could do your own function whit those like:

Code:

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function inserts(str1,str2,pos)
    str3 = string.sub(str1,1,pos)
    str4 = str3 .. str2 .. string.sub(str1,pos,string.len(str1))
    return str4
end
-- to use it like
str1 = "abdefg"
str1 = inserts(str1,"c",2)

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dident test but i supose it should work. good luck

Thanks for the function ahrimanes, a lot of help it was. I had to mod it a tiny bit though as it would insert the text but with the preceeding letter in front of it as well. For example, to insert "???" into "abc" at number 2, it would return "ab???bc". Here is the simple fix:

function InsertString(str1,str2,po s)
str3 = string.sub(str1,1,pos)
str4 = str3 .. str2 .. string.sub(str1,pos + 1,string.len(str1))
return str4
end

Thanks again. Do you know why the \n escape sequence does not enter a new line?

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Zitat von romulator

Do you know why the \n escape sequence does not enter a new line?

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I think i do. The line break technically is in the string as i've seen it working when you save a string with a line break into a text file. I think that when you print the string it replaces the character with the one that you see.

LuaPlayer print text function doesn't support linebreaks. No other reason really.

I have a image with a player on it and I was able to get it on the screen and move it. My problem is that I don't know how to remove the background from the player image (blue).

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Zitat von yaustar

LuaPlayer print text function doesn't support linebreaks. No other reason really.

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Well if this is true, then how will you print half of a string on one line and half on the next? Man this is starting to frustrate me. And if Lua does not support this, why is it included in the lua dev kit snippets?

remove the line that says clear:image blue or something like that. I havent done lua in a while.

romulator move onto C OR C++ if you are getting frustrated.

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Zitat von sony psp player

I have a image with a player on it and I was able to get it on the screen and move it. My problem is that I don't know how to remove the background from the player image (blue).

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Make a .png with a alpha channel. The easiest way i can think of is making the image in photoshop with no color/transparent as background and saving as a .png. If you are using paint though you have no way of adding transparency. .png transparency is very useful too, you can get not only full transparency but also anything between 1~99% too.

My only gripe about the lua transparency support is that when you blit a image with transparency onto another image you will lose all transparency. What made it worse is that you can't create an image with transparency by script (easily and resource freindly).

Can I add transperency with the gimp?

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Zitat von romulator

Well if this is true, then how will you print half of a string on one line and half on the next? Man this is starting to frustrate me. And if Lua does not support this, why is it included in the lua dev kit snippets?

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Lua's default print function that prints to the console supports line breaks. LuaPlayer print to screen function that prints to the screen doesn't.

How can I use the default functions that print to the console or am I stuck to figure out a way on my own? (It's 12:33 am so I'm very tired). Thanks for your help anyway yaustar if you can't figure this out.

I only knew about the screen:Print function when i used lua. Never knew of another way ...

Yaustar would it be easier for me to go to C if i plan on using the gu because i have something lined up now.

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Zitat von romulator

How can I use the default functions that print to the console or am I stuck to figure out a way on my own? (It's 12:33 am so I'm very tired). Thanks for your help anyway yaustar if you can't figure this out.

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print("text")

Ummm I tried that and that didn't help. Unless you could explain further, I won't be able to do it.

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Zitat von sony psp player

Can I add transperency with the gimp?

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Assuming you've got the image saved as a png:

Go to Select>By Color
Click on your background (make sure your background is a color not used anywhere else on your sprite)
Go to Layer>Transparency>Color to Alpha
Choose your background color by clicking on the color box
Click OK.

If that transparency option is greyed out, there should be one that isn't, which is Add Alpha Channel. Guess what that does.

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Zitat von romulator

How can I use the default functions that print to the console or am I stuck to figure out a way on my own? (It's 12:33 am so I'm very tired). Thanks for your help anyway yaustar if you can't figure this out.

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This is sort of what the Lua Code Challenge 3 was on Evilmana.com:
http://forums.evilmana.com/index.php?topic=601.15

Have a look at the last post (#20), you can use whatever you need from it, if you like. I believe I commented it pretty well.

ok, i have this really simple jump theory, here is the code with the animation and the problem is that it doesn't come back down when prompted to

Code:

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standright = Image.load("images/jack/jackstandright.png")
jump = Image.load("images/jack/jackjumpright1.png")
jump2 = Image.load("images/jack/jackjumpright2.png")
jump3 = Image.load("images/jack/jackjumpright3.png")
player = {}
player.x = 20
player.y = 200
player.img = standright
Timer1 = 0

function jumpright()

Timer1 = Timer1 + 1


        if Timer1==5 then

        player.img = jump

        end



        if Timer1==10 then

        player.img = jump2

        end


                if Timer1==15 then
 
                player.img = jump3

                end

while true do  ----MAIN LOOP----

oldx = player.x
oldy = player.y


screen:clear()


pad = Controls.read()

if pad:up() then
jumpright()
player.y = player.y + 10  --player y is 20 so if you add it it will go 30
end

if pad:up() and player.y == 30 then 
--since player y is 30 because of the last loop, i want it to come back down to 20

player.y = player.y + 10
end

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

screen.flip()
oldpad = pad
screen.waitVblankStart()
end

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also, when the animatin stops, it won't clear the scrren and replaye it with player.img, even with the running animation

the function is only being called one time, specifically when the button is pressed. No button, no function. Try using a flag like player.jumping = true and have a function run while that flag is true and not run when it is false.

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Zitat von moncristo_da_dev

ok, i have this really simple jump theory, here is the code with the animation and the problem is that it doesn't come back down when prompted to

Code:

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standright = Image.load("images/jack/jackstandright.png")
jump = Image.load("images/jack/jackjumpright1.png")
jump2 = Image.load("images/jack/jackjumpright2.png")
jump3 = Image.load("images/jack/jackjumpright3.png")
player = {}
player.x = 20
player.y = 200
player.img = standright
Timer1 = 0

function jumpright()

Timer1 = Timer1 + 1


        if Timer1==5 then

        player.img = jump

        end



        if Timer1==10 then

        player.img = jump2

        end


                if Timer1==15 then
 
                player.img = jump3

                end

while true do  ----MAIN LOOP----

oldx = player.x
oldy = player.y


screen:clear()


pad = Controls.read()

if pad:up() then
jumpright()
player.y = player.y + 10  --player y is 20 so if you add it it will go 30
end

if pad:up() and player.y == 30 then 
--since player y is 30 because of the last loop, i want it to come back down to 20

player.y = player.y + 10
end

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

screen.flip()
oldpad = pad
screen.waitVblankStart()
end

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also, when the animatin stops, it won't clear the scrren and replaye it with player.img, even with the running animation

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you should give animlib a try. (unless you already have).

Now I have a image with an alpha channel. How do I use it in lua?

This is my code, but it doesn't work:
screen:blit(movey, movex, player, alpha = true)

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Zitat von romulator

How can I use the default functions that print to the console or am I stuck to figure out a way on my own? (It's 12:33 am so I'm very tired). Thanks for your help anyway yaustar if you can't figure this out.

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The short answer is that you write your function that parses the string for line breaks and prints the text in the right positions.
-= Double Post =-

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Zitat von eldiablov

I only knew about the screen:Print function when i used lua. Never knew of another way ...

Yaustar would it be easier for me to go to C if i plan on using the gu because i have something lined up now.

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It be easier in some ways and harder in others. In short, I honestly don't know. You still have to face the same challenges but the difference is that it be in a different language.

If it was me, I would just use an existing engine (eg LTE) rather then re-inventing the wheel.

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Zitat von sony psp player

Now I have a image with an alpha channel. How do I use it in lua?

This is my code, but it doesn't work:
screen:blit(movey, movex, player, alpha = true)

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The alpha is true as default in the image:blit() function, you don't need to type true or false.

Code:

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screen:blit(movey, movex, player, alpha = true)

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The red area is the error, why you saw 'alpha = true' in the LUA function page is because they were stating to the user that it represents the boolean of the alpha to the blitting.

Code:

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screen:blit(movey, movex, player, true)

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But as i said it's default, so you don't need it.

Thanks!

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Zitat von Grimfate126

you should give animlib a try. (unless you already have).

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i don't want to put that big code in the beginning, i just want to blit and play a sprite animation, so can you give me the code simplified for that?