Lua Programming Help Thread

[youresam]

The GU code must be wrong then.

[SG57]

yum - You could always make a loader that flips an image's pixels across either axis... This would only have to be done at loading time as it's a whole new image, without having to have a new external image.

Loop through each pixel in the image you want flipped, and write it's color data to it's flipped position in the new image. I might just try to write one up for the sake of seeing if it works...

[youresam]

yum - You could always make a loader that flips an image's pixels across either axis... This would only have to be done at loading time as it's a whole new image, without having to have a new external image.

Loop through each pixel in the image you want flipped, and write it's color data to it's flipped position in the new image. I might just try to write one up for the sake of seeing if it works...

Which would be so slow for 32 images that it would take like a minute to "load"

This has been done many times, and the only way of achieving a good result would be to flip it in C, as lua is too slow for pixel-by-pixel operations.
Epic phale.

[xpack]

Cant remember what is the offset for the nickname besides the 0x2380 in know it was somthing like 0x9????

[romulator]

0x980

[waywardson]

anyone know some code that can make a character animation to look as though hes sabbing then return to the position he was it right before he stabed after you let go the button???
i made it work but when i push the button he stabs and stays in the stabbed position ??
any help would be apprecated

[Nicko01]

Check out this code i made in around 45 seconds.
it cycles through all the colors the psp is capable of displaying (which is 16,581,375 colors). It would take approximately between 3 and 3.7 days to see them all.

background = Image.createEmpty(480,272)
r = 0
g = 0
b = 0
while true do
color = Color.new(r,g,b)
background:clear(color)
screen:blit(0,0,background)
if r < 255 then
r = r + 1
end
if r == 255 then
r = 0
g = g + 1
end
if g == 255 then
g = 0
b = b + 1
end
screen.waitVblankStart()
screen.flip()
end

and here is a code which draws parabolas all over the screen. This is the result of combining random code together to made something completely unexpected. this code is really not clean. a lot of it is not necessary.

math.randomseed( os.time() )
green = Color.new(0,255,0)
white = Color.new(255,255,255)
black = Color.new(0,0,0)
bullet = Image.createEmpty(4,4)
bullet:clear(green)
player = {}
player.gravity = 500
player.y = 230
player.x = 50
pdir = "left"
player.jumpspeed = 10
player.jumpstate = "ground"
oldpad = Controls.read()
currentBullet = 0
BulletInfo = {}
for a = 1,1000 do
BulletInfo[a] = { pic = bullet , firing = false, direction = "right", x = player.x + 32,
y = player.y }
end
function bulletSetup()
if currentBullet < 1000 then
currentBullet = currentBullet + 1
else
currentBullet = 1
end
if dir == "left" then
BulletInfo[currentBullet].direction = "left"
BulletInfo[currentBullet].x = player.x
BulletInfo[currentBullet].y = player.y
end
if dir == "right" then
BulletInfo[currentBullet].direction = "right"
BulletInfo[currentBullet].x = player.x
BulletInfo[currentBullet].y = player.y
end
BulletInfo[currentBullet].direction = direction
BulletInfo[currentBullet].firing = true
end
function bulletFire()
for i = 1,1000 do
if BulletInfo[i].firing == true then
if BulletInfo[i].direction == "right" then BulletInfo[i].x = BulletInfo[i].x + 10 end
if BulletInfo[i].direction == "left" then BulletInfo[i].x = BulletInfo[i].x - 10 end
screen:blit(BulletInfo[i].x,BulletInfo[i].y,BulletInfo[i].pic)
end
if BulletInfo[i].x < 0 or BulletInfo[i].x > 480 or BulletInfo[i].y < 0 or BulletInfo[i].y > 272 then BulletInfo[i].firing = false end
end
end
f1 = Image.load("f1.png")

ground = Image.createEmpty(480,10)
ground:clear(black)


while true do
r = math.random(225)
g = math.random(225)
b = math.random(225)
color = Color.new(r,g,b)
bullet:clear(color)

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

bulletSetup()
bulletFire()



if walk == 1 then
walk = 2
else
walk = 1
end


if player.jumpstate == "ground" then player.jumpstate = "jumping"
end
if player.jumpstate == "jumping" then
player.jumpspeed = player.jumpspeed - 0.5
player.gravity = player.gravity - player.jumpspeed
end
if player.gravity < 0 then
player.jumpstate = "falling"
end
if player.gravity < 230 and player.jumpstate == "falling" then
player.gravity = player.gravity + (player.jumpspeed + 3)
end
if player.gravity == 230 then
player.jumpspeed = 10
player.jumpstate = "ground"
end

if player.gravity > 230 then player.gravity = 230
end
player.y = player.gravity

screen:blit(player.x,player.y,f1)
if pdir == "left" then
player.x = player.x - 2
end
if pdir == "right" then
player.x = player.x + 2
end
if player.x == 480 then
dir = "left"
pdir = "left"
end
if player.x == 0 then
dir = "right"
pdir = "right"
end

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

heres another one which flashes random colors and says "w00t" in another random color and a random x and y.

math.randomseed( os.time() )
background = Image.createEmpty(480,272)
while true do
screen:clear()
x = math.random(480)
y = math.random(272)
r = math.random(255)
g = math.random(255)
b = math.random(255)
fontcolor = Color.new(b,r,g)
color = Color.new(r,g,b)
background:clear(color)
screen:blit(0,0,background)
screen:print(x,y,"w00t",fontcolor)
screen.waitVblankStart()
screen.flip()
end

[myschoo]

x = math.random(272) --- it should be 480
y = math.random(480) --- it should be 272
r = math.random(225) --- its should be 255
g = math.random(225) --- same
b = math.random(225) --- same
fontcolor = Color.new(b,r,g) --- it should be R G B

[Nicko01]

no, if it was r,b,g, it would be the same color as the background.
ill fix the other stuff, i told you i made it in less than a minute.

[myschoo]

oh yeah... text...my bad

[Grimfate126]

no, if it was r,b,g, it would be the same color as the background.
ill fix the other stuff, i told you i made it in less than a minute.

thats not a good excuse. you might as well spend 2 days on something and make it good, rather than make sucky stuff in 45 seconds. and your first sentence makes no sense. just because you use it like its b, g, r, doesnt mean its supposed to be like that. ;)

also, another reminder to all coders out there (especially beginners), start indenting. i simple tab makes your code 50 times easier to read. for example:

ugly, non-indented code:

if a == 1 then
if b == 2 then
if c == 3 then
if d == 4 then
d = 1
end
end
end
end

same code, with indentations:

if a == 1 then
   if b == 2 then
      if c == 3 then
         if d == 4 then
            d = 1
	 end
      end
   end
end

[waywardson]

anyone know some code that can make a character animation to look as though hes sabbing then return to the position he was it right before he stabed after you let go the button???
i made it work but when i push the button he stabs and stays in the stabbed position ??
any help would be apprecated

just bumping this up so i can get help

[KleptoOne]

object states. ie

pad = Controls.read()
if pad:cross() then
    obj.attacking = true
else
    obj.attacking = false
end
if obj.attacking then
    screen:blit(x,y,stabbing)
else
    screen:blit(x,y,notstabbing)
end

[waywardson]

thanks a bunch man!!!!!!

[emericaska8r]

what was the point of that stuff you posted nicko01?

[TacticalPenguin]

Nicko- Displaying all the colors in 7 lines (way shorter):

for i = 1, 255 do
for j = 1, 255 do
for k = 1, 255 do
screen:clear(Color.new(i,j,k))
end
end
end

[SG57]

TP - Try all the colors minus 765 ( i think )

for r = 0, 255 do
  for g = 0, 255 do
    for b = 0, 255 do
      screen:clear(Color.new(r,g,b))
    end
  end
end

Does the alpha channel add as well? Also, in Lua, do the for loops have a < or a <= for the number of loops to do?

[TacticalPenguin]

Oh yea lol I forgot 0. And transparency might make a difference but I don't think so. If so then that's like 4-5 billion different backgrounds.

edit: 4228250625

[SG57]

Yeah, transparency doesn't count apparently, as 256 cubed = 16,777,216 where 256 ^ 4 (what's after cubed?) = 4,294,967,296. The reason I think they dont count alpha channel is because having any pixel have an alpha channel (any transparency at all) will just be black as what;s underneathe it is nothing (either that, or just wont do anything as there isnt anything underneathe it)

[Bob Hoil]

I am using different collsion then before in my shell but i am having problems. I don't encounter an error but it doesn't work.
Here is my code:

background=Image.load("images/menu.png")
fb=Image.load("images/fb.png")
fbclicked=Image.load("images/fbclicked.png")
apps=Image.load("images/apps.png")
appsclicked=Image.load("images/appsclicked.png")
wb=Image.load("images/wb.png")
wbclicked=Image.load("images/wbclicked.png")
games=Image.load("images/games.png")
gamesclicked=Image.load("images/gamesclicked.png")
mp=Image.load("images/mp.png")
mpclicked=Image.load("images/mpclicked.png")
white=Color.new(255,250,250)
cursor = Image.load("images/cursor.png")

sensitivity = 40
maxspeed = 3

cursor = {x = 30, y = 100, w = 32, h = 32, oldx = 200, oldy = 50, img = Image.load

("images/cursor.png"), s = 4}

cursorHeight = 32
cursorWidth = 32

button={}
button[1] = {x = 21, y = 234, height = fb:height(), width = fb:width()}
button[2] = {x = 210, y = 234, height = apps:height(), width = apps:width()}

function moveCursor()
pad=Controls.read()
if pad:analogX() < -sensitivity or pad:analogX() > sensitivity then
     cursor.x = cursor.x + pad:analogX()/(128/maxspeed)
end
if pad:analogY() < -sensitivity or pad:analogY() > sensitivity then
     cursor.y = cursor.y + pad:analogY()/(128/maxspeed)
end
end

function clock()
time = os.time()
timestring = os.date("%c",time)
timeinfo = os.date("*t", time)
hour = timeinfo.hour
if hour > 11 then ampm = "PM"
elseif hour < 12 then ampm = "AM"
end
min = timeinfo.min
if min < 10 then
min = "0" .. min
end
hour = timeinfo.hour
if hour > 12 then
hour = hour - 12
end
screen:print(325, 26,hour..":" ..min .. " "..ampm, white)
end

function collisionCheck(object)
if (cursor.x + cursorWidth > object.x) and (cursor.x < object.x + object.width) and (cursor.y + 

cursorHeight > object.y) and (cursor.y < object.y + object.height) then
end
end

function button3()
if pad:cross() and collisionCheck(button[1]) then 
dofile("fb.lua")
end
end

function button4()
if pad:cross() and collisionCheck(button[2]) then 
dofile("apps.lua")
end
end

function screenPrint()
screen:blit(0,0,background)
screen:blit(21,234,fb)
screen:blit(113,234,mp)
screen:blit(210,234,apps)
screen:blit(305,234,games)
screen:blit(399,234,wb)
screen:blit(cursor.x,cursor.y,cursor.img)
screen:print(424,26, System.powerGetBatteryLifePercent(),white)
end

while true do
screen:clear()

collisionCheck(button[1])
collisionCheck(button[2])

moveCursor()

button3()

button4()

screenPrint()

clock()

screen.waitVblankStart()
screen.flip()
end

I was trying not to post here for help and do it on my own but i can't figure it out.

Thanks Bob Hoil

[KleptoOne]

You're not returning true or false in your collision function.

[yumCOOKIEZZ]

Hmm...I was thinking about making my game online. I was kinda curious but I'm not sure if I should do it or not. I know Youresam made netlib and that would probably be what I need, but I haven't the slightest idea of how to use it. I just wanna know basic things about it, like how I could make someones character appear on my PSP screen...


Help is cool.

[PSPJunkie_]

You display the variables yourself. The coordinates of the image are what you actually send.

[Bob Hoil]

Thanks I got it working. Can't believe i forgot that.:Argh:

[yumCOOKIEZZ]

You display the variables yourself. The coordinates of the image are what you actually send.

I'm guessing that was directed at me, and you completely lost me.
How would I even get things to send. I have no idea how to use it, and nothing on the internets explains it for complete noobs like me.


And I'm guessing if I wanted to go anywhere with the game I would need a dedicated server?

[PSPJunkie_]

Look at the source of online.lua from the online sonic game. Youresam actually wrote that so it should be all good.

[SG57]

yum - You need to understand how to design a networked game.

My idea on how to do it would be to have a huge list (table in lua i guess) and compare data recieved from the other player with it, and act accordingly:

action = {
    "move left",
    "move right",
    "move up",
    "move down",
    "attack"
}

recieved_data = ""

while true do
    recieved_data = getDataSentFromOtherPSP()

    if recieved_data == action.move_left then
        Opponent.moveLeft()
    elseif recieved_data == action.move_right then
        Opponent.moveRight()
    elseif recieved_data == action.move_up then
        Opponent.moveUp()
    elseif recieved_data == action.move_down then
        Opponent.moveDown()
    elseif received_data == action.attack then
        Opponent.attack()
    end
end

I havent tested it, so I don't know if it's the most efficient method, however, it's the most logical method I could create (I thought of this method last summer and have stuck with it).

I may just test it this summer sometime for the sake of knowing how to properly design a networked game.

[youresam]

netlib isnt running right now though...want me to turn it on..?

And SG57- lua is different from C in that it doesnt support define's, so what is received will probably be best to just compare to a string.

[Bob Hoil]

Are there any tutorials on how to use fonts? I have never used them and i am going to use a new font instead of the default one in lua player. I know how to load them(very easy) i just don't know how to make my text use the font.

[emericaska8r]

screen:frontPrint(font, x, y, text, color)