Lua Programming Help Thread

[pspfreak9]

i already have a chasePlayer function though, do i make another?

Well I dont see it whats your error or prob anyways?

[Urameshi]

well the game runs, but when Urameshi chases the player, he shows no animation what so ever, but i want him to show animation

[k0ud]

red = Color.new(255, 0, 0)
Blue = Color.new(0,0,200)

function PrintCentered(y,string,color)
screen:print( 240 - (string.len(string)*8) / 2 ,y,string,color);
end

Background = Image.load("background1.png")

System.Unassign("flash0:" )

System.Assign("flash0:", "lflash0:0,0", "flashfat0:")


current = 1
oldpad = Controls.read()

while true do

pad = Controls.read()

screen:blit(0,0,Background)
PrintCentered(3,"Lua Theme Flasher", Blue)
PrintCentered(18,"By ai3gtmc", Blue)
screen:print(137, 96, "=> 01-12.bmp background", Blue)
screen:print(137, 106, "=> TopMenu_Plugin", Blue)
screen:print(137, 116, "=> Opening_Plugin", Blue)
screen:print(137, 126, "=> Gameboot.PMF", Blue)
screen:print(137, 136, "=> System_Plugin_bg", Blue)
screen:print(137, 146, "=> System_Plugin_fg", Blue)
screen:print(137, 156, "=> System_Plugin", Blue)
screen:print(137, 166, "=> Game_Plugin", Blue)
screen:print(137, 176, "=> photo_plugin", Blue)
screen:print(137, 186, "=> impose_plugin", Blue)
screen:print(137, 196, "=> ltn0.pgf", Blue)
screen:print(137, 210, "=> Enable USB", Blue)
screen:print(137, 220, "=> Disable USB",Blue)
screen:print(137, 240, "=> EXIT", Blue)




if current == 1 then
screen:print(137, 96, "=> 01-12.bmp background", red)
end

if current == 2 then
screen:print(137, 106, "=> TopMenu_Plugin.rco", red)
end

if current == 3 then
screen:print(137, 116, "=> Opening_Plugin.rco", red)
end

if current == 4 then
screen:print(137, 126, "=> Gameboot.PMF", red)
end


if current == 5 then
screen:print(137, 136, "=> System_Plugin_bg.rco", red)
end

if current == 6 then
screen:print(137, 146, "=> System_Plugin_fg.rco", red)
end

if current == 7 then
screen:print(137, 156, "=> System_Plugin.rco", red)
end

if current == 8 then
screen:print(137, 166, "=> Game_Plugin.rco", red)
end

if current == 9 then
screen:print(137, 176, "=> photo_plugin.rco", red)
end

if current == 10 then
screen:print(137, 186, "=> impose_plugin.rco", red)
end

if current == 11 then
screen:print(137, 196, "=> ltn0.pgf", red)
end

if current == 12 then
screen:print(137,210, "=> Enable USB!", red)
end

if current == 13 then
screen:print(137,220, "=> Disable USB!", red)
end


if current == 14 then
screen:print(137, 240, "=> EXIT", red)
end



if pad:up() and oldpad:up() ~= pad:up() then
current = current-1
end

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

if current == 15 then
current = 1
end

if current == 0 then
current = 14
end



if pad:cross() and current == 1 then
System.writeFile("ms0:/theme/01-12.bmp","flash0:/vsh/resource/01-12.bmp","yes")
end

if pad:cross() and current == 2 then
System.writeFile("ms0:/theme/topmenu_plugin.rco","flash0:/vsh/resource/topmenu_plugin.rco","yes")
end

if pad:cross() and current == 3 then
System.writeFile("ms0:/theme/opening_plugin.rco","flash0:/vsh/resource/opening_plugin.rco","yes")
end


if pad:cross() and current == 4 then
System.writeFile("ms0:/theme/gameboot.pmf","flash0:/vsh/resource/gameboot.pmf","yes")
end


if pad:cross() and current == 5 then
System.writeFile("ms0:/theme/system_plugin_bg.rco","flash0:/vsh/resource/system_plugin_bg.rco","yes")
end

if pad:cross() and current == 6 then
System.writeFile("ms0:/theme/system_plugin_fg.rco","flash0:/vsh/resource/system_plugin_fg.rco","yes")
end

if pad:cross() and current == 7 then
System.writeFile("ms0:/theme/system_plugin.rco","flash0:/vsh/resource/system_plugin.rco","yes")
end

if pad:cross() and current == 8 then
System.writeFile("ms0:/theme/game_plugin.rco","flash0:/vsh/resource/game_plugin.rco","yes")
end

if pad:cross() and current == 9 then
System.writeFile("ms0:/theme/photo_plugin.rco","flash0:/vsh/resource/photo_plugin.rco","yes")
end

if pad:cross() and current == 10 then
System.writeFile("ms0:/theme/impose_plugin.rco","flash0:/vsh/resource/impose_plugin.rco","yes")
end

if pad:cross() and current == 11 then
System.writeFile("ms0:/theme/ltn0.pgf","flash0:/font/ltn0.pgf","yes")
end

if pad:cross() and current == 12 then
System.usbDiskModeActivate()
end

if pad:cross() and current == 13 then
System.usbDiskModeDeactivate()
end

if pad:cross() and current == 14 then
System.Quit()
end


---ScreenShot---
if pad:select() then
Image:save("screenshot.png")
end

if pad:start() then
System.Quit()
end

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

end

this works for me, repaired some errors... try it

hmm can u tell me what did u repair?...

i dont have a psp right now

i gave my psp to my bro as a graduation gift:)

[myschoo]

only 2 things:


sometimes you used Red and sometimes red in your menu so i changed it all to "red" and then you were flashing font to flash0:/vsh/font/ and thats not right

[emericaska8r]

well the game runs, but when Urameshi chases the player, he shows no animation what so ever, but i want him to show animation

try either using animLib, or do something like:

function animateweirdnamedguy()
	movingstate = movingstate + 1
	if movingstate>= 48 or movingstate<=0  then
		movingstate = 0
	elseif movingstate < 12 then
		player.image = right1
	elseif movingstate < 24 then
		player.image = right2
	elseif movingstate < 36 then
		player.image = right3
	elseif movingstate < 48 then
		player.image = right4
	end
end

[k0ud]

only 2 things:


sometimes you used Red and sometimes red in your menu so i changed it all to "red" and then you were flashing font to flash0:/vsh/font/ and thats not right

u mean i can't flash fonts?

whats wrong with the font script?

[Cynical]

Hey, hope someone can help me out on this. I started to learn lua 2 days ago. After going through some tutorials, i thought id start with a pong game.
so i coded everything, did some graphics and now i have one problem:

My game has a menu with 4 choices. 2 player mode, survival mode, credits and quit. (not everything is finished yet).
everytime i start one of the modes, get out of it and try another one, get out of that one and try to start another one the third time, the psp freezes. :Argh:
Why is it doing that? hope someone knows a solution.

[SG57]

Cynical - I havanet looked at your code, but my guessis your not managing your resources correctly. You need to make sure you set ALL variables used in your source to 'nil', without hte quotes, before 'dofile'ing to another script (in your case that is). Than you need to call collectgarbage() to erase all traces of you varaibles from RAM.

ex:

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

function Cleanup()
     image = nil
     collectgarbage()
end

while true do
     screen:blit(0,0,image)

     pad = Controls.read()
     if pad:cross() then
         Cleanup()
         dofile("game.lua")
     end

     screen.waitVblankStart()
     screen.flip()
end

[KleptoOne]

Yeah, its definately a memory issue, whats happening is you're loading the same images over and over without releasing them. What I usually like to do is set all my loads into a function, i.e.

function loadmultiplayergfx()
(load all your images)
end

and the immediately create an unload function, i.e.

function unloadmultiplayergfx()
(set all your images to null and collect garbage)
end

This way its as easy as calling the load at the beginning of the mode, and unloading as you leave the mode. Plus in your loading function you can blit a loading screen, making your app that much more presentable. Also remember that if you store images into an array of any type, you have to null the array before you collect garbage or lua actually won't free the memory.

[SG57]

Oh - good point. Make sure you free any references to any variable. By this, i mean:

bg1 = Image.load("bg.png")
-- why waste time reloading the same image?  just feed the same image data into a new image variable
bg2 = bg1

...

function Cleanup()
    bg1 = nil
    -- collectgarbage() <- BOO BOO!  bg2 still is referencing to bg1, and freeing bg1 will have bg2 reference to nothing (nothing as in, not an 'Image' type)
    bg2 = nil
    collectgarbage()
end

Klepto - I did the same as well in my Call of Duty 2 - PSP Edition. My unload function was quite long asthe Lua doesnt support the multiple variable setting (var1 = var2 = var3 = nil doesnt work). I didnt know about the collectgarbage function until i read the Lua manual. Good thing too *sigh of relief*

[myschoo]

u mean i can't flash fonts?

whats wrong with the font script?

font is located in flash0:/font/ not flash0:/vsh/font/ ;)
-= Double Post =-

Cynical - I havanet looked at your code, but my guessis your not managing your resources correctly. You need to make sure you set ALL variables used in your source to 'nil', without hte quotes, before 'dofile'ing to another script (in your case that is). Than you need to call collectgarbage() to erase all traces of you varaibles from RAM.

ex:

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

function Cleanup()
     image = nil
     collectgarbage()
end

while true do
     screen:blit(0,0,image)

     pad = Controls.read()
     if pad:cross() then
         Cleanup()
         dofile("game.lua")
     end

     screen.waitVblankStart()
     screen.flip()
end

that collectgarbage() function is inside lua player or you have to create it??

[k0ud]

font is located in flash0:/font/ not flash0:/vsh/font/ ;)
-= Double Post =-


that collectgarbage() function is inside lua player or you have to create it??

oh man thx:) u rock:Punk:

[myschoo]

but still does it work?

[k0ud]

but still does it work?

hmm i still dont have a psp

[myschoo]

ok , tell me then

[Cynical]

Cynical - I havanet looked at your code, but my guessis your not managing your resources correctly. You need to make sure you set ALL variables used in your source to 'nil', without hte quotes, before 'dofile'ing to another script (in your case that is). Than you need to call collectgarbage() to erase all traces of you varaibles from RAM.

ex:

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

function Cleanup()
     image = nil
     collectgarbage()
end

while true do
     screen:blit(0,0,image)

     pad = Controls.read()
     if pad:cross() then
         Cleanup()
         dofile("game.lua")
     end

     screen.waitVblankStart()
     screen.flip()
end

Oh ok, I kinda suspected it had something to do with the the memory. (at one point I got a "mikmod critical error, out of memory"). Anyways,
should i also do the garbage collecting for variables that contain for examples just integers or strings? or is it only necessary for variables containing images?
I will try some garbage collection right now, thanks for the answers :)
@ Klepto - do you mean it like this:

function loadgfx()
image = Image.load("image.png")
end

function unloadgfx()
image = nil
collectgarbage()
end

loadgfx()

while true do
...
unloadgfx
dofile "..."
end

EDIT:
Now, the problem, that the psp freezes the third time trying to load a mode, is solved. but now i have the problem, that after a few times i try to load a mode, i get the following error:

LuaPlayer's mikmod has a critical error:
_mm_critical 0
_mm_errno 5
Sample load failed - Out of memoy

???

[Merick]

I've been looking into coroutines, can someone tell my why this isn't working?

chain = {}
chain.img = {}
chain.img[1] = Image.load("./gfx/tiles/1.png")
chain.img[2] = Image.load("./gfx/tiles/2.png")
chain.img[3] = Image.load("./gfx/tiles/3.png")
chain.head = {x = 30, y = 30}
chain.anchor = {x = 240, y = 136}
chain.segment = {}
chain.segment[1] = coroutine.create(function (head, anchor)
	local newX = ((head.x + anchor.x)/2)+ math.random(-3, 3)
	local newY = ((head.y + anchor.y)/2) + math.random(-3, 3)
	screen:blit(newX, newY, chain.img[2])
	coroutine.yield()
	end)

loop = true
while loop do
	pad = Controls.read()
	
	if pad:left() and chain.head.x > 10 then chain.head.x = chain.head.x -1 end
	if pad:right() and chain.head.x < 470 - chain.img[1]:width() then chain.head.x = chain.head.x +1 end
	if pad:up() and chain.head.y > 10 then chain.head.x = chain.head.x -1 end
	if pad:down() and chain.head.y < 262 - chain.img[1]:height() then chain.head.x = chain.head.x +1 end

	screen:clear()
	coroutine.resume(chain.segment[1](chain.head, chain.anchor))
	screen:blit(chain.head.x, chain.head.y, chain.img[1])
	screen:blit(chain.anchor.x, chain.anchor.y, chain.img[3])
	screen:waitVblankStart()
	screen:flip()
	
	if pad:start() then loop = false end
end

when the program gets to the coroutine.resume it exits with the error:

attempt to call field '?' (a thread value)

[KleptoOne]

From what I read, the benefit of coroutines is that it allows you to stop a function, and resume it at a later time. Concerning your code, when you call the resume, you cannot pass new variables, you simply must pass the thread name, ie.

coroutine.resume(chain.se gment[1])

another problem with your code is that your yield is at the end of your coroutine, so basically once its resumed, it runs through completely and is then killed. You will have to create a new thread if you want to have it run again, so in a sense you have just created a standard function.

Does anyone know how lua handles dead thread by the way?

[Merick]

Actually, according the "Programming in Lua" you can pass arguments. And looking at that page again, I see what I did wrong. I was trying to pass the arguments inside brackets like you would with a normal function, but when resuming coroutines you're already inside a set of brackets so you just use commas, like this:

coroutine.resume(chain.segment[1](chain.head, chain.anchor)) -- bad

coroutine.resume(chain.segment[1], chain.head, chain.anchor) -- good

And as for putting yield at the end, the simple solution too keep the thread from dying is to put the whole code block into a loop.

According to what I've read, resuming a coroutine takes up less processor time than calling a regular function so I was thinking that they would be perfect for keeping track of enemy ai

[KleptoOne]

gotcha, the loop makes a lot of sense. I'll have to read up some more on this, any idea as to how much of a performance gain you would achieve by using this method?

[Merick]

No idea really, and in fact it might be possible that I mis-read something.

[sony psp player]

If I receive data from the ir port, how can I print it to the screen and how do I save it to a file?

[Access_Denied]

Well, I've never used the IR port, but I assume that it's stored in a variable. So, to print it, do something like this:

foo = IR.read() --not actual function, just used as example
screen:print(10,10,foo,black)

To write it to a file:

file = io.open("file.txt","w")
file:write(foo)
file:close()

[KleptoOne]

Page 598, IR was discussed a little bit. Heres the link:

Link

[sony psp player]

Thanks!
-= Double Post =-
OK, but how can I read from a saved file and send the content of this file over ir?

[youresam]

file = io.open("file.txt","r")
System.irdaSend(file:read ("*a"))
file:close()

I forgot the IR function.

[ClearTranquil]

I've been struggling with this since yesterday...

What I want to do is have the Move 25 pixels event happen 3 times over a period of 1 second...not have the character move 75 pixels instantly...

I've tried timers and counters and the animation script but I only started coding 4 days ago and still don't know how to get this to work. I wish Lua worked like RPG Maker where you could just go "Wait(100)" for it to wait a second before proceeding...

--MOB COLLISION--

if MobX - 15 <= CleoX and CleoX <= MobX + 10 and MobY - 35 <= CleoY and CleoY <= MobY + 15 then
	Kill:play( )
	if cleodown then CleoY = CleoY -25 end
	if cleoleft then CleoX = CleoX +25  end
	if cleoright then CleoX = CleoX -25  end
	if cleoup then CleoY = CleoY +25 end
	screen:blit(CleoX,CleoY,cleo[direction])
	HP = HP - 1
end

[KleptoOne]

I've been struggling with this since yesterday...

What I want to do is have the Move 25 pixels event happen 3 times over a period of 1 second...not have the character move 75 pixels instantly...

I've tried timers and counters and the animation script but I only started coding 4 days ago and still don't know how to get this to work. I wish Lua worked like RPG Maker where you could just go "Wait(100)" for it to wait a second before proceeding...

--MOB COLLISION--

if MobX - 15 <= CleoX and CleoX <= MobX + 10 and MobY - 35 <= CleoY and CleoY <= MobY + 15 then
	Kill:play( )
	if cleodown then CleoY = CleoY -25 end
	if cleoleft then CleoX = CleoX +25  end
	if cleoright then CleoX = CleoX -25  end
	if cleoup then CleoY = CleoY +25 end
	screen:blit(CleoX,CleoY,cleo[direction])
	HP = HP - 1
end

screen:waitVblankStart(60 ) will pause the screen for 1 second. just make sure you slip the screen in between each call.

[ClearTranquil]

What do you mean slip the screen?

[Merick]

i think he meant flip