Lua Programming Help Thread

[Access_Denied]

Thanks slicer4ever. You gave me the basic idea.

[slicer4ever]

access look back a page i just tried to help you

[Access_Denied]

Yeah, I just seen that. Thanks.

[Ralan]

I have images bilting then biltig again, Can i put in a 1 second wait between these?

[slicer4ever]

i'm testing the code i wrote i just can't remeber the image.createnew command i know it's sometin like that

edit: @ralan try it and see what happens or post your code is it working like you want or not?

[PSPduh]

i'm testing the code i wrote i just can't remeber the image.createnew command i know it's sometin like that

edit: @ralan try it and see what happens or post your code is it working like you want or not?

player = Image.createEmpty(height,width)
player:clear(color)

That what you're looking for?

[LMelior]

@ Grimfate126

If you haven't figured it out yet, have a look at the entry for "table.maxn" in the Lua 5.1 Reference Manual. This seems like it would work if you have a simple one dimensional table like the example you made. If there are two dimensions, though, things may get a little hairy.

If that doesn't work for you, you'd have to write your own function to find it, which might not be easy at all, because Lua will probably quit on you if you try to reference a nonexistent entry in a table. I think there's a way to get around that but I couldn't tell you what it is (assert, maybe?).


@ Access_Denied

You could always do it the simple way and put a screen.waitVblankStart(#) right after the program finds a button press. Something like this:

if pad:down() then
screen.waitVblankStart(7)
end

You'll have to tinker with the input argument to find a value you like.

(I also had something like what slicer posted but he beat me to it)

Hope this helps.

[slicer4ever]

thanks pspduh

ok access this works for moving a character just hold down the left button=-)

blue = Color.new(0,0,255)
black = Color.new(0,0,0)
player = Image.createEmpty(5,5) -- i know it's sometin like that
player:clear(blue)

button = "no"
time_held = 0
x = 240
y = 0
oldpad = pad

while true do
screen:fillRect(0,0,480,272,black)
pad = Controls.read()
if time_held < 60 then
if pad:left() then
time_held = time_held + 1
else
time_held = 0
end
if pad:left() and oldpad:left() ~= pad:left() then
x = x - 1
end
end
if time_held > 59 then
if pad:left() then
x = x - 1
else
time_held = 0
end
end
screen:blit(x,y,player)
screen.flip()
screen.waitVblankStart()
oldpad = pad
end

i tested it and i know it works=-)

[PSPduh]

thanks pspduh

Your welcome. :)

I haven't posted in this thread in a while...

[Grimfate126]

At line 7 it's Controls.read() not Conrol.read(). You have to put the "s" in controls.
-= Double Post =-
Does anyone know of a way where if I hold down the UP/DOWN button, it scrolls fast, but if I just tap it, it scrolls one at a time. Like in the PSP's XMB.

simple way:

oldpad = Controls.read()

if pad:down() and oldpad:down() = pad:down() then
statusbar = statusbar + 10
end

if pad:down() and oldpad:down() ~= pad:down() then
statusbar = statusbar + 1
end

[slicer4ever]

edit:nvm i figure out a diffrent way
-= Double Post =-
ok here you go access all 4 directions:

blue = Color.new(0,0,255)
black = Color.new(0,0,0)
player = Image.createEmpty(15,15) -- i know it's sometin like that
player:clear(blue)

button = "no"
time_held = 0
x = 240
y = 0
oldpad = pad

while true do
screen:fillRect(0,0,480,272,black)
pad = Controls.read()
if pad:left() then
if time_held < 60 then
time_held = time_held + 1
if pad:left() and oldpad:left() ~= pad:left() then
x = x - 1
end
end
if time_held > 59 then
x = x - 1
end
end
if pad:right() then
if time_held < 60 then
time_held = time_held + 1
if pad:right() and oldpad:right() ~= pad:right() then
x = x + 1
end
end
if time_held > 59 then
x = x + 1
end
end
if pad:up() then
if time_held < 60 then
time_held = time_held + 1
if pad:up() and oldpad:up() ~= pad:up() then
y = y - 1
end
end
if time_held > 59 then
y = y - 1
end
end
if pad:down() then
if time_held < 60 then
time_held = time_held + 1
if pad:down() and oldpad:down() ~= pad:down() then
y = y + 1
end
end
if time_held > 59 then
y = y + 1
end
end
if pad:left() and oldpad:left() ~= pad:left() then
time_held = 0
end
if pad:right() and oldpad:right() ~= pad:right() then
time_held = 0
end
if pad:up() and oldpad:up() ~= pad:up() then
time_held = 0
end
if pad:down() and oldpad:down() ~= pad:down() then
time_held = 0
end
screen:blit(x,y,player)
screen.flip()
screen.waitVblankStart()
oldpad = pad
end

tested to work

[Grimfate126]

edit:nvm i figure out a diffrent way
-= Double Post =-
ok here you go access all 4 directions:

blue = Color.new(0,0,255)
black = Color.new(0,0,0)
player = Image.createEmpty(15,15) -- i know it's sometin like that
player:clear(blue)

button = "no"
time_held = 0
x = 240
y = 0
oldpad = pad

while true do
screen:fillRect(0,0,480,272,black)
pad = Controls.read()
if pad:left() then
if time_held < 60 then
time_held = time_held + 1
if pad:left() and oldpad:left() ~= pad:left() then
x = x - 1
end
end
if time_held > 59 then
x = x - 1
end
end
if pad:right() then
if time_held < 60 then
time_held = time_held + 1
if pad:right() and oldpad:right() ~= pad:right() then
x = x + 1
end
end
if time_held > 59 then
x = x + 1
end
end
if pad:up() then
if time_held < 60 then
time_held = time_held + 1
if pad:up() and oldpad:up() ~= pad:up() then
y = y - 1
end
end
if time_held > 59 then
y = y - 1
end
end
if pad:down() then
if time_held < 60 then
time_held = time_held + 1
if pad:down() and oldpad:down() ~= pad:down() then
y = y + 1
end
end
if time_held > 59 then
y = y + 1
end
end
if pad:left() and oldpad:left() ~= pad:left() then
time_held = 0
end
if pad:right() and oldpad:right() ~= pad:right() then
time_held = 0
end
if pad:up() and oldpad:up() ~= pad:up() then
time_held = 0
end
if pad:down() and oldpad:down() ~= pad:down() then
time_held = 0
end
screen:blit(x,y,player)
screen.flip()
screen.waitVblankStart()
oldpad = pad
end

tested to work

thats wayy too long/complicated. my way works better (it not exactly accurate, but right like 99 percent of the time.)

[slicer4ever]

the hard/complicated way may be long but usually it ensures less bugs=-)

[Ralan]

i'm testing the code i wrote i just can't remeber the image.createnew command i know it's sometin like that

edit: @ralan try it and see what happens or post your code is it working like you want or not?

Its way to fast... brb while i find my script

[slicer4ever]

ok well when you do be sure to include what you want it to do

[Grimfate126]

ok guys new problem.

here is my code: ( i have loaded all the images already)

test = {}
frames = 1

test[frames+1] = Timer.new()
test[frames+2] = 1
test[frames+3] = 1

x = 5
y = 5

screen:blit(x, y, test[test[frames+2]])
test[frames+1]:start()

for test[frames+3] = 1, frames do -- THIS IS THE LINE OF THE ERROR--
if test[frames+1]:time() >= ((test[frames+3] -1) * interval) and test[frames+1]:time() <= (test[frames+3] * interval) then
test[frames+3] = test[frames+2]
end
end

the error says: (in windows lua)

ERROR: '=' or 'in' expected near '[''

thx for help!

[PSPMillionaire]

I don't think you can use an array there in the for loop.
Use a temp variable, something like

for x = 1, frames do

[mark.sparky]

hey im working on my new game and ive got the animation done but what i want to know is how do i get my game to know when the button is not pressed and what direction the sprite should be facing. And also is there a way to check how long a button has been pressed for

[Aphonia]

For direction:
if pad:left() then
player.direction= "left"
player.x = player.x - 1
end

For the button, do you mean something like this?(from Snake):

while not Controls.read():start() do

I haven't tested it, but I think that would also work as:
if not Controls.read():start()
--or--
and not Controls.read():start()

and any other command.

[SG57]

... To everyone ...

Please run tests and small example programs, made by you, to learn the basic concept of programming... Once that is understood, the syntax of any language is the real challenge...

So in your case, mark.sparky, there's multiple ways to determine what direction, even with your vague question... As for when a button isnt pressed, Im using the basic concept of the 'not' operator with-in an argument/function returning 1 on pressed, 'not-1' when not pressed... So you do the basic puesdo code for this...

-- I dont know all the syntax of LUA, so w/e the 'not' operator is, use it... Im 
-- guessing it's the ~ thing... in C its the !

while true do
     sg57 = Controls.read()
     
     -- Ex:  Pause
     if ~sg57:start() then
            --While not paused, have movement calls here
     else -- if start is pressed
          -- app now paused...
     end
end

I dont even know probably 1/2 of the LUA syntax as an average LUA coder does, yet i understand the concept/routines to use in accomplishing what you want... It comes in very handy... Anyway, good luck with your new game mark.sparky!

[SG57]

... To everyone ...

Please run tests and small example programs, made by you, to learn the basic concept of programming... Once that is understood, the syntax of any language is the real challenge...

So in your case, mark.sparky, there's multiple ways to determine what direction, even with your vague question... As for when a button isnt pressed, Im using the basic concept of the 'not' operator with-in an argument/function returning 1 on pressed, 'not-1' when not pressed... So you do the basic puesdo code for this...

-- I dont know all the syntax of LUA, so w/e the 'not' operator is, use it... Im 
-- guessing it's the ~ thing... in C its the !

while true do
     sg57 = Controls.read()
     
     -- Ex:  Pause
     if ~sg57:start() then
            --While not paused, have movement calls here
     else -- if start is pressed
          -- app now paused...
     end
end

I dont even know probably 1/2 of the LUA syntax as an average LUA coder does, yet i understand the concept/routines to use in accomplishing what you want... It comes in very handy... Anyway, good luck with your new game mark.sparky!

[Access_Denied]

How do you exit the program and go back to the XMB? Besides using the "HOME" button?

[PSPduh]

How do you exit the program and go back to the XMB? Besides using the "HOME" button?

I think break; or break works. Like:

if pad:cross() then
break; -- I think it's break, try both ways. break; and break.
end

[Jeremy1026]

How do you exit the program and go back to the XMB? Besides using the "HOME" button?

you can't exit back to the XMB from LUA. Only back to a Lua Browser (if app. is launched from within the same Lua Browser)

[Access_Denied]

Well my PSP is currently unavailable, but I tried "break" on LUA Player for Windows and it immedately exited the program. So I think it worked.

[PSPduh]

@Jeremy - If that's the case, then it need to be a stand alone eboot, then do break and it will exit back to the XMB.

@Access_Denied - I'm not sure if it is going to exit to the XMB or the lua browser, since with the computer you can't tell.

[Branin]

Well, I have tried this with an eboot. using the break function just gives you a black screen with the text, Press start to restart.

[Access_Denied]

I'm using a standalone EBOOT. But if it doesn't work, I'll just settle with the home button. Unless anyone else knows a way?

[Jeremy1026]

@Jeremy - If that's the case, then it need to be a stand alone eboot, then do break and it will exit back to the XMB.

@Access_Denied - I'm not sure if it is going to exit to the XMB or the lua browser, since with the computer you can't tell.

in a standalone eboot the "break" command simply restarts the lua application.

[LMelior]

You have to use unofficial Luaplayer versions, such as v0.17dk2 by Dark Killer or v0.20 mod by Cools, both of which have a System.Quit() function (Cools got his from Dark Killer's) that "exits Lua Player back to the psp browser." I haven't tested this yet but I assume it works. I'm sure somebody here could confirm this.