Lua Programming Help Thread

[yaustar]

Anyone know whats wrong with this?

housey < packy + pack:width()

Using width for a y axis check? Should be height.

[TacticalPenguin]

For a racing game and a speed variable, something like:

player = { x = 0, y = 0, img = Image.load("player.png"), d = u }
speed = 0
if pad:cross() and speed > maxspeed then
speed = speed+1
elseif pad:square() and speed > 0 then
speed = speed - 3
end
if speed < 0 then speed = 0 end
if player.x > 472 - player.img:width() and player.d == r then
player.x = player.x + speed
end
if player.x > 472 - player.img:width() then player.x = 472 - player.img:width()

Theres a basis for ya. Just dont forget to make a reverse!

[GuitarGod1134]

ok thanks its late right now but ill look into that tomorrow il... put u in the credits or something lol.
EDIT: nvm i dont feel like doing spanish 2 homework right now lol.

[Yongobongo]

Ok, my game is nearly done, yay! But I want to be able to fire something more then once, like so if i fire eg. a bullet it doesnt just get rid of it and fire another on from the starting point?

[psp11]

Yongobongo, what are you trying to say?

[Yongobongo]

How can I fire multiple bullets, basically :)

[Access_Denied]

How can I fire multiple bullets, basically :)

http://www.evilmana.com/tutorials/lu...et_bullets.php

That should work. If not, I can probably help you.

[TacticalPenguin]

Yep and if 5 isnt enough just edit it a little to have more, but keep it to as few as possible.

[EminentJonFrost]

i need to know how to clear up RAM. my game switches between scripts alot and i just got to the point where i now need to load...alot of stuff and need more space cause i dont want for it to lag...

[TacticalPenguin]

imageyouloadedbeforethaty ounolongerneed = nil
asnotherimageyoupreviousl yloadedthatyounolongernee d = nil
imagethatyounowneed = Image.load("image.png")

Also, make sure your code isn't wasting your PSP's cpu or anything, just go through it and check for better ways of doing things and unneccessary things.

[EminentJonFrost]

just calling them "nil" does that?

that just sounds too easy...ok!

[TacticalPenguin]

Yea just make sure there arent multiple vcalues usin the same image. Making the m nil just redefines them as undefined and with an image sitting undefined and unused in the ram, it gets dumped out.

[HeaD_ShOt]

is there a site that says what all teh lua error messages mean so i can understand where i made my error?

[yaustar]

is there a site that says what all teh lua error messages mean so i can understand where i made my error?

That is what the line number in the error messages are for. Most of the errors are straight forward, others will require you to mentally step though the code to find your error. I also find that with scripts in general (weakly typed and usually with no debuggers) Hungarian Notation helps a lot especially during code maintenance and expansion.

[HeaD_ShOt]

great now i got rid of the errors and now it just freezes the psp
what can cause that to happen?

[yaustar]

Overflowing the stack, infinite loops are the immediate two that comes to mind.

[HeaD_ShOt]

waht does <eof> mean?

[TacticalPenguin]

End of file. Generally it means you need to go through and check that you ended all of your loops and ifthens.

[psp11]

I used to get that message all the time until I realized that my pc took longer than 2 seconds to transfer over the files. First you will see the memstick light blink then about 10 seconds later it will blink again, then you can disconnect it.

[HeaD_ShOt]

System.usbDiskModeActivat e()

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

bg = Image.load("background.pn g")

screen:blit(0,0,bg)
screenrint(120,140,"play game",black)
screenrint(120,150,"Controls",b lack)
screenrint(120,160,"Credits",bl ack)
screen:flip()

current = 1
while true do
pad = Controls.read()
screen:clear()

if current == 1 and pad:cross() then
do file("game.lua")
end
if current == 2 and pad:cross() then
dofile("help.lua")
end
if current == 3 and pad:cross() then
dofile("credits.lua")
end

if current == 1 then
screenrint(120,140,"play game",green)
end
if current == 2 then
screenrint(120,150,"Controls",g reen)
end
if current == 3 then
screenrint(120,160,"Credits",gr een)
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 == 4 then
current = 1
end
if current == 0 then
current = 3
end
screen.waitvblankStart()
screen.flip()
oldpad = pad
end

i cant seem to get this to work
this is teh menu

[Access_Denied]

i cant seem to get this to work
this is teh menu

You need to put all your screenrints and screen:blits inside your main loop, since you have a screen:clear() in your main loop. If you put them before the loop, they will just get wiped away by the screen:clear().

[HeaD_ShOt]

System.usbDiskModeActivat e()

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

screenrint(120,140,"loading..." ,white)
screen:flip()

bg = Image.load("background.pn g")

current = 1
pad = Controls.read()
screen:clear()

if current == 1 and pad:cross() then
do file("game.lua")
end
if current == 2 and pad:cross() then
dofile("help.lua")
end
if current == 3 and pad:cross() then
dofile("credits.lua")
end

screen:blit(0,0,bg)
screenrint(120,140,"play game",black)
screenrint(120,150,"Controls",b lack)
screenrint(120,160,"Credits",bl ack)
screen:flip()

if current == 1 then
screenrint(120,140,"play game",green)
end
if current == 2 then
screenrint(120,150,"Controls",g reen)
end
if current == 3 then
screenrint(120,160,"Credits",gr een)
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 == 4 then
current = 1
end
if current == 0 then
current = 3
end
screen.waitvblankStart()
screen.flip()
oldpad = pad
end

there...
now it just freezes with loading on the screen

[Grimfate126]

there...
now it just freezes with loading on the screen

you dont have a "while true do". try this:

System.usbDiskModeActivat e()

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

screenrint(120,140,"loa ding...",white)
screen:flip()

bg = Image.load("background.pn g")

current = 1

while true do

pad = Controls.read()
screen:clear()

if current == 1 and pad:cross() then
do file("game.lua")
end
if current == 2 and pad:cross() then
dofile("help.lua")
end
if current == 3 and pad:cross() then
dofile("credits.lua")
end

screen:blit(0,0,bg)
screenrint(120,140,"pla y game",black)
screenrint(120,150,"Con trols",black)
screenrint(120,160,"Cre dits",black)
screen:flip()

if current == 1 then
screenrint(120,140,"pla y game",green)
end
if current == 2 then
screenrint(120,150,"Con trols",green)
end
if current == 3 then
screenrint(120,160,"Cre dits",green)
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 == 4 then
current = 1
end
if current == 0 then
current = 3
end
screen.waitvblankStart()
screen.flip()
oldpad = pad
end

[HeaD_ShOt]

then i get an error message saying i need an end for teh 'while'
in "while true do"
where would i put this end?

btw thanks for all your help

[Anti-QuickJay]

I believe since you have a main loop, You have to put the end to end your loop, Or else it will just keep repeating the loop, I think thats right???

[Grimfate126]

I believe since you have a main loop, You have to put the end to end your loop, Or else it will just keep repeating the loop, I think thats right???

the point of a loop IS to repeat. the "end" just puts limits on HOW MUCH you want to repeat every frame.

[Anti-QuickJay]

Ah, Yea ok!

[Anti-QuickJay]

Stickied!

[gameo]

God... now i finnaly got the ball to work with collosion in my ping pong game, thanks to Guitargod..

BUT! (Damm, there's always a but) At the start of the game, the ball is just blitted, and signed as an object, but i need it to move when the game starts!

(Yeah, i know nothing... *sniff*) So what should i write before the game loop, and what do i have to write?

I think my grammer is pretty wrong in this post. Oh well.

[TacticalPenguin]

Just setup the direction system like I showed you and make the ball start out with a direction and then move the ball based on its direction.