Lua Programming Help Thread

[Makubesu]

Hey everyone, hopefully I didn't miss this in the 300 pages worth of discussions we've got here, but can someone explain to me how to use transparencies with LUA?

[Bronx]

ok, just make your picture delete the part you dpnt want seen, then save it as a .png <-- MOST IMPORTATNT STEP RIGHT THERE

[mark.sparky]

grimfate please explain a bit clear what your dong but one quick suggestion is that in your code

name[a] = Image.load("header..a..". png)

put a " in it so it looks like this

name[a] = Image.load("header"..a.." .png")

[SG57]

Hey everyone, hopefully I didn't miss this in the 300 pages worth of discussions we've got here, but can someone explain to me how to use transparencies with LUA?

Easy... Get some image editor that supports adding an alpha layer, then add one to a PNG, and erase w/e to transparency ;)

[mark.sparky]

hey sg57 could you please help me with my lua animation code coz i cannot get it right

[Makubesu]

*tries it out*
Wow, it even supports png-24, this is great! Thanks for your help.

[Grimfate126]

grimfate please explain a bit clear what your dong but one quick suggestion is that in your code

name[a] = Image.load("header..a..". png)

put a " in it so it looks like this

name[a] = Image.load("header"..a.." .png")

that wont work cause 'header' has been gotten from the function, hence putting it in "" would make the image: header1.png/header2.png etc. instead of the header that i gave the function.


explainition:

ok, i want to load these images:

test1.png all the way to test6.png
char1.png to char9.png
AND
misc1.png to misc5.png

i want them in their own arrays. so i made a function:

function make(header, frames, name)

  name = {}
 
    for a = 1, frames do
        name[a] = Image.load(header..a..".png")
    end

end

so that i could call it like this:

make(test, 6, test_array)
make(char, 9, char_array)
make(misc, 5, misc_array)

BUT, i have a prob.

when i say :

name = {}

i want the name of that array to be whatever i give to that function (such as test_array, char_array, and misc_array) BUT, the function make an array named "name" insted of test_array... etc.

i want it so that the array is named what i give the function.






P.S. sry, its confusing i know.

[mark.sparky]

why do you want the test_array etc to be called "name" or something else

[Grimfate126]

why do you want the test_array etc to be called "name" or something else

???

OK, try TWO- ACTION!


i am making an app. for it i need to load these images:

test1.png
test2.png
test3.png
test4.png
test5.png
test6.png

i want all those images in an array called:

test_array

then i have ANOTHER set of images:

char1.png
char2.png
char3.png
char4.png
char5.png
char6.png
char7.png
char8.png
char9.png

i want these images in an array called:

char_array

i have a THIRD set of images (the last set):

misc1.png
misc2.png
misc3.png
misc4.png
misc5.png

i want these images in an array called:

misc_array

NOW.. i can make all the arrays and load the images by hand but its MUCH faster with a function, SO i made a function to make the array, and load the images into it:

function make(header, frames, name)

  name = {}
 
    for a = 1, frames do
        name[a] = Image.load(header..a..".png")
    end

end

NOW, i called the function like this

make(test, 9, test_array)
make(char, 6, char_array)
make(misc, 5, misc_array)

BUT, the function does not work properly. the problem is that everytime i call it the function makes an array by the name of:

name

and not the name i give it. (such as test_array, or char_array, or misc_array)


NOW do u get it?


BTW, i wont tell what app im making yet. ;)

[xiringu]

I think this link could be handy:

http://www.lua.org/pil/14.1.html

I've used that before to dynamically create the name of variables, and I think that's what you want to do, right?

[LMelior]

@grimfate

I think the problem is that since you have that "name={}" line inside the function definition, it overwrites the input variable passed to the function. I'm pretty sure that if you initialize the arrays outside of the function (right before you call the function), then pass the name of the array into the function, it will work. Does that even make sense? :)

Basically, what I'm trying to say is change the "make" function to this:

function make(header, frames, name)
 
    for a = 1, frames do
        name[a] = Image.load(header..a..".png")
    end

end

And then call it like this:

test_array={}
char_array={}
misc_array={}
make(test, 9, test_array)
make(char, 6, char_array)
make(misc, 5, misc_array)

At least, that makes sense in my head.

[Makubesu]

Won't the array generated by your function only be local to that function anyways? Give the function a return value, and call it like this:
char_array = {}
char array = make(char, 6)
would be my advice.

[LMelior]

Won't the array generated by your function only be local to that function anyways?

EDIT: Ah, sorry about that Makubesu, you were right! I forgot that "name" was a function input variable, which are indeed local to the function no matter how you define them inside there.

[Grimfate126]

LMelior, and Makubesu both of your ideas are good, BUT the nature on my program NEEDS those arguments to be inside a function.

sry, i cant tell u what im working on yet. sry.



xiringu: ill read that and get bak 2 u. thx!

[LMelior]

LMelior, and Makubesu both of your ideas are good, BUT the nature on my program NEEDS those arguments to be inside a function.

sry, i cant tell u what im working on yet. sry.

Oh I don't mind not knowing, but the result of the code that Makubesu described is exactly what you asked for - arrays of images that are named exactly as you wanted them.

The exact results of the code you posted are in three empty, global tables named "test_array," "char_array," and "misc_array," plus a table called "name" with 9 images that is local to the "make" function. The first five images will be your miscellaneous images, the sixth image will be the last character image, and the last three images will be your last three test images.

The exact results of the following code are three global tables with the same names as above with 9, 6, and 5 images, respectively:

function make(header, frames)
    local name={}
    for a = 1, frames do
        name[a] = Image.load(header..a..".png")
    end
    return name
end
------
test_array=make(test,9)
char_array=make(char,6)
misc_array=make(misc,5)

You do realize that if you use your current "make" function elsewhere, you could use this code and rename the function? I can't really think of any other situation in which you'd absolutely need those three inputs.

[Grimfate126]

Oh I don't mind not knowing, but the result of the code that Makubesu described is exactly what you asked for - arrays of images that are named exactly as you wanted them.

The exact results of the code you posted are in three empty, global tables named "test_array," "char_array," and "misc_array," plus a table called "name" with 9 images that is local to the "make" function. The first five images will be your miscellaneous images, the sixth image will be the last character image, and the last three images will be your last three test images.

The exact results of the following code are three global tables with the same names as above with 9, 6, and 5 images, respectively:

function make(header, frames)
    local name={}
    for a = 1, frames do
        name[a] = Image.load(header..a..".png")
    end
    return name
end
------
test_array=make(test,9)
char_array=make(char,6)
misc_array=make(misc,5)

You do realize that if you use your current "make" function elsewhere, you could use this code and rename the function? I can't really think of any other situation in which you'd absolutely need those three inputs.

yes, i totally understand. but ill release it soon once i get this prob fixed. any more ideas?

[mark.sparky]

can someone tell me what is worng with this code coz when i run it it says on line 49 'end expected (to close to 'whle' at lin 27 ) near 'elseif':

hear is my code. line 49 and 27 is marked out.


--function for movement and animation
function moveAni()

while pad:down() do   --    line 27
animation = animation + 1
link[1].face = down
link[1].y = link[1].y + 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, down1)
end
if animation >= 7 and animation < 14 then
down1:clear(down2)
end
if animation >= 14 and animation < 21 then
down2:clear(down3)
end
if animation >= 21 and animation < 28 then
down3:clear(down4)
end
if animation >= 28 and animation < 35 then
down4:clear(down1)
end
if animation == 35 then
animation = 7
end 
elseif link[1].face == down then    -- line 49
screen:blit( link[1].x, link[1].y, down1)
animation = 0
end
end
while pad:up() do
animation = animation + 1
link[1].face = up
link[1].y = link[1].y - 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, up1)
end
if animation >= 7 and animation < 14 then
up1:clear(up2)
end
if animation >= 14 and animation < 21 then
up2:clear(up3)
end
if animation >= 21 and animation < 28 then
up3:clear(up4)
end
if animation >= 28 and animation < 35 then
up4:clear(up1)
end
if animation == 35 then
animation = 7
end
elseif link[1].face == up then
screen:blit( link[1].x, link[1].y, up1)
animation = 0
end
end
while pad:right() do
animation = animation + 1
link[1].face = right
link[1].x = link[1].x + 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, right1)
end
if animation >= 7 and animation < 14 then
right1:clear(right2)
end
if animation >= 14 and animation < 21 then
right2:clear(right3)
end
if animation >= 21 and animation < 28 then
right3:clear(right4)
end
if animation >= 28 and animation < 35 then
right4:clear(right1)
end
if animation == 35 then
animation = 7
end
elseif link[1].face == right then
screen:blit( link[1].x, link[1].y, right1)
animation = 0
end
end
while pad:left() do
animation = animation + 1
link[1].face = down
link[1].x = link[1].x - 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, down1)
end
if animation >= 7 and animation < 14 then
down1:clear(down2)
end
if animation >= 14 and animation < 21 then
down2:clear(down3)
end
if animation >= 21 and animation < 28 then
down3:clear(down4)
end
if animation >= 28 and animation < 35 then
down4:clear(down1)
end
if animation == 35 then
animation = 7
end
elseif link[1].face == down then
screen:blit( link[1].x, link[1].y, down1)
animation = 0
end
end
end

[psp4life]

can someone tell me what is worng with this code coz when i run it it says on line 49 'end expected (to close to 'whle' at lin 27 ) near 'elseif':

hear is my code. line 49 and 27 is marked out.


--function for movement and animation
function moveAni()

while pad:down() do   --    line 27
animation = animation + 1
link[1].face = down
link[1].y = link[1].y + 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, down1)
end
if animation >= 7 and animation < 14 then
down1:clear(down2)
end
if animation >= 14 and animation < 21 then
down2:clear(down3)
end
if animation >= 21 and animation < 28 then
down3:clear(down4)
end
if animation >= 28 and animation < 35 then
down4:clear(down1)
end
if animation == 35 then
animation = 7
end 
end -- FIXED, needed an end there ( I think)
elseif link[1].face == down then    -- line 49
screen:blit( link[1].x, link[1].y, down1)
animation = 0
end
end
while pad:up() do
animation = animation + 1
link[1].face = up
link[1].y = link[1].y - 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, up1)
end
if animation >= 7 and animation < 14 then
up1:clear(up2)
end
if animation >= 14 and animation < 21 then
up2:clear(up3)
end
if animation >= 21 and animation < 28 then
up3:clear(up4)
end
if animation >= 28 and animation < 35 then
up4:clear(up1)
end
if animation == 35 then
animation = 7
end
elseif link[1].face == up then
screen:blit( link[1].x, link[1].y, up1)
animation = 0
end
end
while pad:right() do
animation = animation + 1
link[1].face = right
link[1].x = link[1].x + 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, right1)
end
if animation >= 7 and animation < 14 then
right1:clear(right2)
end
if animation >= 14 and animation < 21 then
right2:clear(right3)
end
if animation >= 21 and animation < 28 then
right3:clear(right4)
end
if animation >= 28 and animation < 35 then
right4:clear(right1)
end
if animation == 35 then
animation = 7
end
elseif link[1].face == right then
screen:blit( link[1].x, link[1].y, right1)
animation = 0
end
end
while pad:left() do
animation = animation + 1
link[1].face = down
link[1].x = link[1].x - 0.5
if animation <= 6 then
screen:blit( link[1].x, link[1].y, down1)
end
if animation >= 7 and animation < 14 then
down1:clear(down2)
end
if animation >= 14 and animation < 21 then
down2:clear(down3)
end
if animation >= 21 and animation < 28 then
down3:clear(down4)
end
if animation >= 28 and animation < 35 then
down4:clear(down1)
end
if animation == 35 then
animation = 7
end
elseif link[1].face == down then
screen:blit( link[1].x, link[1].y, down1)
animation = 0
end
end
end

look at line 49.

[mark.sparky]

ok thnx ill try that
-= Double Post =-
that doesnt work coz now it says "line 50 erorr: 'end' expected (to colse function at line 25) near 'elseif'

[psp4life]

oh, I don't know what's the problem then, sorry. maybe put the end under the animation = 0 line at line 49?

[mark.sparky]

but if i do that then it will end that function will it not

[psp4life]

probably.

[Glynnder]

well. It means you have missed out an end somewhere

[mark.sparky]

well alex can you look at the code

[Glynnder]

ok, what page is it on?
-= Double Post =-
im leaving any second now, soo i might now have time to help

[LMelior]

The problem is that you end all of your "if" statements. You can't have an "elseif" if there are no open "if" statements. You aren't using "elseif" correctly. The reason it is good to use "elseif" is because the first time that any one of those statements triggers, the code will skip the rest of the "elseif" choices.

So, the best way for your code to be written is:

if a then
-- do one thing
elseif b then
-- do something else
elseif c then
-- do something else
else
-- do the default action
end

To answer your question directly, you did not need an extra end there, but you should have taken the one that was there out! But it would be easier to understand if you wrote it as above.

[mark.sparky]

bu the only probably them with that is that i have started the whole animation with a while loop. So cna you not write elseif in a whlie loop

[LMelior]

bu the only probably them with that is that i have started the whole animation with a while loop. So cna you not write elseif in a whlie loop

Yes, you can. I recommend using an editor that has syntax highlighting and automatic tabs, because it makes finding errors like that a ton easier. Take a look at the following: no more forgetting what "end" goes with what function.

while pad:down() do
    if a then
        -- do one thing
    elseif b then
        -- do something else
    elseif c then
        -- do something else
    else
        -- do the default action
    end
end

[mark.sparky]

ok ill try that and i use Context text editor

[Glynnder]

how would i send a file with IrDA?
-= Double Post =-
load it into and agrgument and then save the arugument to the other PSP?

would that work.
-= Double Post =-
so
gogo = file.ioopen(entry.name)

system.irdawrite(gogo)
blah blah

then on the other PSP

blah blah.
system.idraread(gogo)
file.iosave(gogo)