Lua Programming Help Thread

[the undead]

hey sg57 how would i do that?...would be like

actually i have no clue, can you help me...il give u credit if you do, lol

[eyece]

sounds like all he needs to do to speed it up is increase an integer somewhere

actually its a little harder than that, its currently slow because it loops through every pixel on the screen each frame, thats 130,560 pixels it has to deal with, per-frame.
well thats what it used to do, he's changed it so it only loops through the section the text is in, witch is like one 20th of the screen (20x faster).

[myschoo]

Can lua right to flash 0? and 1?

if u mean write, then probably not, i wanted to test it, but definetly can read from flash0/1

[Blake1]

I've upgraded my pong code from ealier in this thread (if you saw it...).

Spoiler for My code:

-- Colors
white = Color.new(255, 255, 255);
red = Color.new(255,0,0)
-- paddle image
paddleimg = Image.createEmpty(10, 60)
paddleimg:clear(white)
-- ball image
ballimg = Image.createEmpty(5,5 )
ballimg:clear(white)
-- score
score1 = 0
score2 = 0
---Direction
direction = "none"
direction2 = "none"
Bstartdir = math.random(1,2)
-- paddles
paddle = { }
paddle[1] = { x = 5, y = 100, img = paddleimg }
paddle[2] = { x = 465, y = 100, img = paddleimg }
-- ball
ball = { }
ball[1] = { x = 240, y = 130, img = ballimg }
-- screen
screenwidth = 480 - paddleimg:width()
screenheight = 272 - paddleimg:height()
-- speed
speed = 2
-- Collision Detection Function
function collision(x1, y1, w1, h1, x2, y2, w2, h2)
if (y2 >= y1 and y1 + h1 >= y2) or (y2 + h2 >= y1 and y1 + h1 >= y2 + h2) or (y1 >= y2 and y2 + h2 >= y1) or (y1 + h1 >= y2 and y2 + h2 >= y1 + h1) then
if x2 >= x1 and x1 + w1 >= x2 then
return true
elseif x2 + w2 >= x1 and x1 + w1 >= x2 + w2 then
return true
elseif x1 >= x2 and x2 + w2 >= x1 then
return true
elseif x1 + w1 >= x2 and x2 + w2 >= x1 + w1 then
return true
end
end
return false
end
function movePlayer1( )
if pad:up() and paddle[1].y > 0 then
paddle[1].y = paddle[1].y - speed
end
if pad:down() and paddle[1].y < screenheight then
paddle[1].y = paddle[1].y + speed
end
end
function movePlayer2( )
if pad:triangle() and paddle[2].y > 0 then
paddle[2].y = paddle[2].y - speed
end
if pad:cross() and paddle[2].y < screenheight then
paddle[2].y = paddle[2].y + speed
end
end
while true do
screen:clear()
-- store player's position at beginning of each loop
oldx = ball[1].x
oldy = ball[1].y
screen:clear()
screen:print(220, 15, ""..score1, red)
screen:print(255, 15, ""..score2, red)
screen:blit(paddle[1].x, paddle[1].y, paddleimg )
screen:blit(paddle[2].x, paddle[2].y, paddleimg )
screen:blit(ball[1].x, ball[1].y, ball[1].img )
pad = Controls.read()
movePlayer1( )
movePlayer2( )
---Direction
if direction == "left" then
ball[1].x = ball[1].x - speed
end
if direction == "right" then
ball[1].x = ball[1].x + speed
end
if direction2 == "up" then
ball[1].y = ball[1].y - speed
end
if direction2 == "down" then
ball[1].y = ball[1].y + speed
end
---ball start direction
if Bstartdir == 1 then
direction = "left"
end
if Bstartdir == 2 then
direction = "right"
end
-- Collision Detection for paddle1
Bstartdir = 0
if collision(ball[1].x, ball[1].y, ball[1].w, ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) then
direction = "right"
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) and pad:up() then
Bstartdir = 0
direction = "right"
direction2 = "up"
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) and pad:down() then
Bstartdir = 0
direction = "right"
direction2 = "down"
beep:play()
end
--- Collision Detection for paddle2
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), P2x, P2y, paddle[1].img:width(), paddle[1].img:height()) then
Bstartdir = 0
direction = "left"
beep:play()
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[2].x, paddle[2].y, paddle[2].img:width(), paddle[2].img:height()) and pad:triangle() then
Bstartdir = 0
direction = "left"
direction2 = "up"
beep:play()
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[2].x, paddle[2].y, paddle[2].img:width(), paddle[2].img:height()) and pad:cross() then
Bstartdir = 0
direction = "left"
direction2 = "down"
beep:play()
end

screen.waitVblankStart()
screen.flip()
end

But I'm getting this error:

error: index.lua:47: attempt to perform local arithmatic on local 'w1' (a nil value)

I think this means that you cant 'do math' on that variable, but all the other dummy variables in that function luaPlayers fine with.....

Oh, and thanks to BlackShark whos code has been great to learn from! (Hope thats OK.... :o )

[BlackShark]

hehe, its cool, I just hope it helps ( and I see another great Pong game that rivals mine )

EDIT: the reason that comes up is because you have not defined w1 yet, w1 in this case would be the width of what ever object that applies to, weather ball or paddle. I don't think you defined the X's and Y's in there either, you'll probably get an error for those soon enough to if you don't define them!

[Yongobongo]

Can someone help me? I've never gotten the error before, but when exiting my main game.lua file and reloading it, i get the error "Loop ingettable"

Any help please?

[Blake1]

hehe, its cool, I just hope it helps ( and I see another great Pong game that rivals mine )

EDIT: the reason that comes up is because you have not defined w1 yet, w1 in this case would be the width of what ever object that applies to, weather ball or paddle. I don't think you defined the X's and Y's in there either, you'll probably get an error for those soon enough to if you don't define them!

Thanks for your help BlackShark, but isnt the w1 variable a dummy var? (ie its only used in the function and arent defined, and whatever values are parsed through it through the function call change the variables.
eg.

white = Color.new(255,255,255)
 
function maths(x, y) -- dummy vars are x and y
return x * y         -- these are not declared
end
 
while true do
num1 = 1
num2 = 2
test = maths(num1, num2)
 
screen:print(0,0, "The number is: " .. test, white)
screen.waitVblankStart()
screen.flip()
end

That works and the variables arent declared, so why does mine not work?

[BlackShark]

technecly,

function maths(x, y) -- dummy vars are x and y
return x * y         -- these are not declared
end

IS defining the x/y variables,
the w1 is supposed to be defined as the with of object 1 or maybe like your paddle, find the width of your paddle, then up in somewhere in your code write

w1 = 10

replace 10 with the actual width of your paddle.

[Blake1]

IS defining the x/y variables,
the w1 is supposed to be defined as the with of object 1 or maybe like your paddle, find the width of your paddle, then up in somewhere in your code write

w1 = 10

replace 10 with the actual width of your paddle.

even if i define it, i still get the same error
EDIT: Does a function accept table values as arguments?

[SG57]

Blake1 - The reason num1 and num2 arent giving you errors in your snippet, is becuase your setting them to a value, and that also means you'd be initlizing it, which means your creating it. Now, if you were comparing num1 and/or num2, than it would give you anerror as for one - there is no value in 'num1' and two, it cant find a variable named num1.

As for the motion blurr thing, yes, eyece explained it quite well. After seeing hte GIF, Im going to cut down on al ayer, so in turn that should boost it by 480*12 x faster. Think someone could test this:

scene = {}
scene[1] = {newcolor = {r=0,g=0,b=0,a=0},
	 finalcolor = Color.new(0,0,0),
	 screencolor = Color.new(0,0,0),
	 image=Image.createEmpty(480,13)}
scene[2] = {newcolor = {r=0,g=0,b=0,a=0},
	 finalcolor = Color.new(0,0,0),
	 screencolor = Color.new(0,0,0),
	 image=Image.createEmpty(480,13)}

scene_num = 1

time = 0
pi = math.atan(1) * 4
i=0
y=0
x=0

screen:clear()
screen.waitVblankStart()
screen.flip()

while true do
     for x=0,479 do
          for y=130,142 do
		scene[scene_num].screencolor = screen:pixel(x,y) -- get pixel color
		scene[scene_num].newcolor = scene[scene_num].screencolor:colors() -- give it to new table
		scene[scene_num].newcolor.a = 255/scene_num-40/scene_num -- edit transparency value
		scene[scene_num].finalcolor = Color.new(scene[scene_num].newcolor.r,scene[scene_num].newcolor.g,scene[scene_num].newcolor.b,scene[scene_num].newcolor.a)
		scene[scene_num].image:pixel(x,y-130,scene[scene_num].finalcolor) -- give that color to the old scene 
          end
     end
     scene_num = scene_num + 1
     if scene_num > 2 then scene_num = 1 end

     screen:clear()

     x = math.sin(pi * 2 / 360 * time) * 150 + 180.5
     screen:print(x, 131, "Does this blur?", Color.new(0,255,0))
     time = time + 1
     if time >= 360 then time = 0 end

     for i=1,2 do screen:blit(0,130,scene[i].image) end 

     screen.waitVblankStart()
     screen.flip()
end

[the undead]

if u mean write, then probably not, i wanted to test it, but definetly can read from flash0/1

im sure their is a wau to do it tho, or atleast i hope so

[Blake1]

SG57 - the arguments that are going into the function are initialised, in an array/table .

[SG57]

Uh... what? The arguments in the function in your snippet are just place holders, in a sense. The best way to learn it, is to learn C's syntax, as it will help you understand programming in general much better.

int maths(int x, int y) { return x*y; }

That is your maths function in C. It returns a whole number (hence the 'int' data type), and hte arguments are being initilized, so no error there. Its just, when you call that function and supply the arguments with a value, than your setting those variables to those values, than running the code within the function...

int some_vars[2];

some_var[0] = maths(3,9)
// whats happening here is...
maths ( x = 3, y = 9 ) { some_vars[0] = 3*9; }

some_var[1] = maths(2,13)
// whats happening here is...
maths ( x = 2, y = 13) { some_vars[1] = 2*13 }

I dont quite understand what you are saying, so please elaborate before i rant some more :Argh:

[eyece]

its doing the same thing SG57, blurring, getting darker, and still showing that clip of the lowser (wtf).

[Blake1]

I know their placeholders. They dont have to be defined outside of the function, right?

But the error im getting is:

error: index.lua:47: attempt to perform local arithmatic on local 'w1' (a nil value)

with this code:

Spoiler for My Code:

-- Colors
white = Color.new(255, 255, 255);
red = Color.new(255,0,0)
-- paddle image
paddleimg = Image.createEmpty(10, 60)
paddleimg:clear(white)
-- ball image
ballimg = Image.createEmpty(5,5 )
ballimg:clear(white)
-- score
score1 = 0
score2 = 0
---Direction
direction = "none"
direction2 = "none"
Bstartdir = math.random(1,2)
-- paddles
paddle = { }
paddle[1] = { x = 5, y = 100, img = paddleimg }
paddle[2] = { x = 465, y = 100, img = paddleimg }
-- ball
ball = { }
ball[1] = { x = 240, y = 130, img = ballimg }
-- screen
screenwidth = 480 - paddleimg:width()
screenheight = 272 - paddleimg:height()
-- speed
speed = 2
-- Collision Detection Function
function collision(x1, y1, w1, h1, x2, y2, w2, h2)
if (y2 >= y1 and y1 + h1 >= y2) or (y2 + h2 >= y1 and y1 + h1 >= y2 + h2) or (y1 >= y2 and y2 + h2 >= y1) or (y1 + h1 >= y2 and y2 + h2 >= y1 + h1) then
if x2 >= x1 and x1 + w1 >= x2 then
return true
elseif x2 + w2 >= x1 and x1 + w1 >= x2 + w2 then
return true
elseif x1 >= x2 and x2 + w2 >= x1 then
return true
elseif x1 + w1 >= x2 and x2 + w2 >= x1 + w1 then
return true
end
end
return false
end
function movePlayer1( )
if pad:up() and paddle[1].y > 0 then
paddle[1].y = paddle[1].y - speed
end
if pad:down() and paddle[1].y < screenheight then
paddle[1].y = paddle[1].y + speed
end
end
function movePlayer2( )
if pad:triangle() and paddle[2].y > 0 then
paddle[2].y = paddle[2].y - speed
end
if pad:cross() and paddle[2].y < screenheight then
paddle[2].y = paddle[2].y + speed
end
end
while true do
screen:clear()
-- store player's position at beginning of each loop
oldx = ball[1].x
oldy = ball[1].y
screen:clear()
screen:print(220, 15, ""..score1, red)
screen:print(255, 15, ""..score2, red)
screen:blit(paddle[1].x, paddle[1].y, paddleimg )
screen:blit(paddle[2].x, paddle[2].y, paddleimg )
screen:blit(ball[1].x, ball[1].y, ball[1].img )
pad = Controls.read()
movePlayer1( )
movePlayer2( )
---Direction
if direction == "left" then
ball[1].x = ball[1].x - speed
end
if direction == "right" then
ball[1].x = ball[1].x + speed
end
if direction2 == "up" then
ball[1].y = ball[1].y - speed
end
if direction2 == "down" then
ball[1].y = ball[1].y + speed
end
---ball start direction
if Bstartdir == 1 then
direction = "left"
end
if Bstartdir == 2 then
direction = "right"
end
-- Collision Detection for paddle1
Bstartdir = 0
if collision(ball[1].x, ball[1].y, ball[1].w, ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) then
direction = "right"
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) and pad:up() then
Bstartdir = 0
direction = "right"
direction2 = "up"
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) and pad:down() then
Bstartdir = 0
direction = "right"
direction2 = "down"
beep:play()
end
--- Collision Detection for paddle2
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), P2x, P2y, paddle[1].img:width(), paddle[1].img:height()) then
Bstartdir = 0
direction = "left"
beep:play()
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[2].x, paddle[2].y, paddle[2].img:width(), paddle[2].img:height()) and pad:triangle() then
Bstartdir = 0
direction = "left"
direction2 = "up"
beep:play()
end
if collision(ball[1].x, ball[1].y, ball[1].img:width(), ball[1].img:height(), paddle[2].x, paddle[2].y, paddle[2].img:width(), paddle[2].img:height()) and pad:cross() then
Bstartdir = 0
direction = "left"
direction2 = "down"
beep:play()
end

screen.waitVblankStart()
screen.flip()
end

But of couse the w1 var is a nil value, if its only a placeholder.

EDIT: Why am I getting that empty code block in my post?

[LMelior]

Blake, look at your third input argument the first time you use the collision function.

[BlackShark]

ya, you still haven't defined it, you need to, put "w1 = 10" or something like that above your function. you can change "10" to what ever the actual width of your paddle is.

[the undead]

any one know how to write to the flash(0 and 1) ive been looking all over the place

[yaustar]

LMelior nailed it

if collision(ball[1].x, ball[1].y, ball[1].w, ball[1].img:height(), paddle[1].x, paddle[1].y, paddle[1].img:width(), paddle[1].img:height()) then
direction = "right"
end

Notice the typo? What the heck is ball[1].w?

[ZeroMega]

Does anyone know how to make .xm files play smoothly?

I put in Music.playFile("moise.xm" , true) and it works, but it plays a note every second and lags my game like crazy.

[GuitarGod1134]

then exchange true with false. and it will play once.

[PSPhakkor]

No, that wont make a difference. The problem is probably due to the psp running out of processing power, or the memory stick constantly being accessed. Try to optimise your code

[zmathue]

any one know how to write to the flash(0 and 1) ive been looking all over the place

theres no writing to flash 0/1 only read access

[the undead]

theres no writing to flash 0/1 only read access

kthanks now i need to learn c and make a lua player mod, lol

know any good tuts?

-edit
actuallyy ill just learn c and make an eboot, so know any good tuts?...lol

[Anti-QuickJay]

Just have someone edit the LUA Player so we can get flash 0 write, But keep in mind LUA was meant for the beginning coders so thats why LUA is easy to learn.

[BlackShark]

if ever a mod was to come out like that, id make a mod flasher like xflash :), but who knows if that would ever be implemented.

[Anti-QuickJay]

I hope it doesn't happen, Too many newb LUA coders will start making stuff related to flash and i can see all the bricks already.

[GuitarGod1134]

No, that wont make a difference. The problem is probably due to the psp running out of processing power, or the memory stick constantly being accessed. Try to optimise your code

If you talking about my post (because I think you are) yes actually it will make a difference. Changing that last variable to false will play the song once or once everytime it is called. Trust me I made a app with a tuner in it.

[Yongobongo]

Can someone help me? I have an error when using dofile() and then loading the same file again...Loop ingettable?

[GuitarGod1134]

Need some code.