Lua Programming Help Thread

[Glynnder]

can u post the code for replacing the yellow pixels with purple?

[Grimfate126]

can u post the code for replacing the yellow pixels with purple?

heres my theory: i havent tried it yet.

first, blit the image. THEN define purple, and yellow, and some vars:

yellow = Color.new(255, 255, 0)
purple = Color.new(102, 0, 153)
a = 0
b = 0

thenif the image is 480X272)

while a < 481 and b < 273 do

color = image.pixel(a,b)
colors = color:colors()

if (color == yellow) then
assert(colors.r == 102)
assert(colors.g == 0)
assert(colors.b == 153)
a = a+1
else
a = a+1
end

if a > 480 then
a = 0
b = b+1
end

end

probably wont work. but its worth a try.

[slicer4ever]

jw...

is there a way to break back to the xmb screen? i'm planning to make it a standalone app but i have an exit in there and i was wondering if there was a way to break back to the xmb screen?

edit: if i dl lua source do i need to re-compile it afterwards?

[Access_Denied]

jw...

is there a way to break back to the xmb screen? i'm planning to make it a standalone app but i have an exit in there and i was wondering if there was a way to break back to the xmb screen?

I asked this question a while back on a different forum. I never got an answer though.
Also, does anybody know how to make gravity? Like if a player jumps, it comes back down.

[slicer4ever]

kinda easy for example if you look at the source of my game(block attack you well see how i did gravity)

but heres an example:

cyan = Color.new(0,255,255)
block = Image.createEmpty(20,20)
block:clear(cyan)

gravity = 1
upmove = 5

block_Array = {}
block_Array[1] = {x = 240, y = 250}

function check_for_jump()
block_array[1].y = block_Array[1].y + gravity
if block_array[1].y > 250 then
block_array[1].y = 250
end
if pad:cross() then
block_Array[1].y = block_Array[1].y - upmove
end
end

while true do
screen:blit(block_array[1].x,block_array[1].y,block)

check_for_jump()

screen.flip()
screen.waitVblankStart()
end

that should work as to simulate sometype of gravity

[Access_Denied]

kinda easy for example if you look at the source of my game(block attack you well see how i did gravity)

but heres an example:

cyan = Color.new(0,255,255)
block = Image.createEmpty(20,20)
block:clear(cyan)

gravity = 1
upmove = 5

block_Array = {}
block_Array[1] = {x = 240, y = 250}

function check_for_jump()
block_array[1].y = block_Array[1].y + gravity
if block_array[1].y > 250 then
block_array[1].y = 250
end
if pad:cross() then
block_Array[1].y = block_Array[1].y - upmove
end
end

while true do
screen:blit(block_array[1].x,block_array[1].y,block)

check_for_jump()

screen.flip()
screen.waitVblankStart()
end

that should work as to simulate sometype of gravity

Thanks, now that I really took a look at it, it's really easy.

[slicer4ever]

well since my other question hasen't been answered i ask a new one:

how do you draw a circle?

i've tried:

screen:drawcirc
screen:fillCirc

thats about it

[fchaos]

well since my other question hasen't been answered i ask a new one:

how do you draw a circle?

i've tried:

screen:drawcirc
screen:fillCirc

thats about it

From the lua code snippets thread :

function drawCirc(where, x, y, radius, color)

	theta = 0

	while theta<=360 do
		where:drawLine((math.sin(  theta)*radius)+x, (math.cos(theta)*radius)+  y, (math.sin(theta+1)*radius  )+x, (math.cos(theta+1)*radius  )+y, color)
		theta = theta+1
	end
end

Plenty of other good snippets in there too.

[slicer4ever]

o well i went to luaplayer.org and looked at ther functions thing ut couldn't find anything there well thanks=-)

edit: what am i surpose to put at the where?

[Access_Denied]

How do you use animated sprites in lua?

[montrob]

Make a timer and for time 1-20 do one animation, 21-40 another animation, etc..

[Access_Denied]

I thought of that, but I thought there would be an easier way.

[pspsalv2]

ok i was wondering if someone could help me with this: so ok i have 2 blocks of the exact same size in which i want to touch and when they do i want them to change to another 2ndary picture i have for them so basicly i want a collision in which they touch a both change pictures because i can't figure it out so yeah thanks in advance

[Grimfate126]

ok i was wondering if someone could help me with this: so ok i have 2 blocks of the exact same size in which i want to touch and when they do i want them to change to another 2ndary picture i have for them so basicly i want a collision in which they touch a both change pictures because i can't figure it out so yeah thanks in advance

search "collisions in lua" and follow hat guide.

[pspsalv2]

i need help with making an object/picture move left and right because i what i seem to be doing is getting it to go only right and stop and not go back left so help[ would be much appreciated.

[Altair]

Can you post your code? Then its easier to help you. Or atleast the part which involves the moving of the character.

[mark.sparky]

hey is there a way to get a character to move and change image while moving. What i mean by this is like when your using a sprite sheet.

Edit: i do actually know how to let the player move just not change images while doing so

[Insert_Witty_Name]

hey is there a way to get a character to move and change image while moving. What i mean by this is like when your using a sprite sheet.

The word you're looking for is 'animation'

[mark.sparky]

yes so do you know how to do it?

[Insert_Witty_Name]

It's been too long since I used Lua to be of any assistance really.

What I would do though is download some of the hundreds of Lua homebrew games that are available and look at their animation code - it's the best way to learn.

[mark.sparky]

thnx anyway even if you are no help

[Bronx]

I remember seeing on the pspdev.org forums a example of animation. I believe is what on page 3, 4 or 5 of the lua section for psp. I'll try looking later if you are too lazy ;).

[mstrhelix]

has anyone got TTLDE1.0 or 2.0 working with new Luaplayer20?? i used them fine on 0.16 but i keep getting a no script found in Luaplayer20...

[cwirsing]

http://www.sendspace.com/file/4jg6xl
Can someone take a look at my load. There is a problem with putting the animation on the screen.

[pspsalv2]

Can you post your code? Then its easier to help you. Or atleast the part which involves the moving of the character.
Today 11:11 AM

okay i tried this:

if x>= 0 and x < 450 then x = x + 2
end
if x == 450 and x>0 then x = x-2
end
but that just makes it stop at the right side forever so yeah please help

[Access_Denied]

okay i tried this:

if x>= 0 and x < 450 then x = x + 2
end
if x == 450 and x>0 then x = x-2
end
but that just makes it stop at the right side forever so yeah please help

I think I may have had this problem before, try this:

if x >= 0 and x <= 250 then
x=x+2
end
if x <= 450 and x >= 0 then
x = x - 2
end

Hope this helps.

EDIT- I just noticed why you get stuck on the right side. You put

if x == 450

that means that if x = 449 then it won't move left. Just change that to <=.

[SG57]

pspsalv2 - Thats because its doing what you told it to. I was kinda bored and had about 5-10 minutes so i made a visual :) You have a loop going on but you dont know it.

Oh and as how to fix it, use a bool.

EDIT- I just noticed why you get stuck on the right side. You put

if x == 450

that means that if x = 449 then it won't move left. Just change that to <=.

Your code still wont work as it applys to the above paradox. Plus, it doesnt matter if he says if it is == 450 as he is improving by 2's, so it WILL hit the 450 mark, then go down, then go back up for being less then 450.

[pspsalv2]

I think I may have had this problem before, try this:


Code:
if x >= 0 and x <= 250 then
x=x+2
end
if x <= 450 and x >= 0 then
x = x - 2
end

Hope this helps.

EDIT- I just noticed why you get stuck on the right side. You put

if x == 450

that means that if x = 449 then it won't move left. Just change that to <=.

thanks but access denied ....

Oh and as how to fix it, use a bool.

yeah im not too sure what that is SG57 so if you or someone else could explain...please

[Grimfate126]

thanks but access denied ....



yeah im not too sure what that is SG57 so if you or someone else could explain...please

a bool is basically a true or false statement. try this:

move_right = false
move_left = false

while true do

if if x >= 0 and x <= 250 then
   move_right = true
   move_left = false
end

if x <= 450 and x >= 0 then
   move_right = false
   move_left = true
end

if move_right == true then
   x = x+2
end
if move_left == true then
   x = x-2
end

end

hiow i helped

[Altair]

Ok im assuming you understand SG57's explanation of why it moves to the right and then stops at 450.
About the boolean thing: a boolean is a variable that can either be "true" or "false".
So lets say you have a variable called "moveleft". While you move to the right, its false. When you are at 450 you set it to true. So you say:

if x == 450 then
moveleft=true
end

Then when its true you say:

if moveleft==true then
x=x-2
end

EDIT: Damn you Grimfate, grrrr!