Lua Programming Help Thread

[PSPHax0r9]

The only thing I can think of is maybe you're loading too many images OR what I think the problem is, is "lv1.png" Is "lv1.png" a huge image? If it is it might be having problems blitting it or even loading it.

[Mast3r_Shak3]

Well the images are like 4kb apiece and the BG is a 480x272 image thats.... wtf... 90kb... maybe thats the problem

EDIT: And it is. Thank you! now I need a new BG

[Mast3r_Shak3]

OKay... umm how do I have it so when I press left on the d-pad a left arrow will show. But when I press right a right arrow shows? (And the left arrow be gone so it doesnt look like <->)

[kozine]

Like this:

right = Image.load("rightarrow.png")
left = Image.load("leftarrow.png")
background = Image.load("background.png")

while true do
pad = Controls.read()

if pad:right() then
screen:blit(0, 0, background)
screen:blit(10, 10, right)
end

if pad:left() then
screen:blit(0, 0, background)
screen:blit(10, 10, left)
end

end

That should work.

[Mast3r_Shak3]

Doesnt really work... It makes it all slow and Im doing it for a sidescrolling engine with multiple images on the screen.

[Vaza]

I know that this is a real noob like question but:
What does the alpha channel in LUA do and how do i use it?
--Vaza

[Paburo]

Something I've noticed when looking through a bunch of the lua homebrew. In platformers, specifically, I see folks making multiple copies of the same sprite so they have a left and right direction of each. I assume that it'd be more convenient to simply mirror the sprite horizontally when drawing, depending on the desired direction. I'd hoped to test it myself, but I've been hard pressed to find a bit of code lending this function. Looking into the lua snippets, I found something that I thought might lead me to an answer, but I've hit a bit of a road block.

The rotate by 90 degrees code,

-- Variables
smile = Image.load("smiley.png")
function rotateImage(theImage)
	newImage = Image.createEmpty(theImage:height(), theImage:width())
	for x = 1, theImage:width() do
		for y = 1, theImage:height() do
			newImage:blit(y, x, theImage, x, y, 1, 1)
		end
	end
	return newImage
end -- rotateImage
--main program
screen:blit(0, 0, smile)
screen:blit(100, 0, rotateImage(smile))
screen:flip()
screen.waitVblankStart(600)

with the included image, seems to show an image being simply rotated by 90 degrees. However, when you change the image, you see that it actually gets mirrored either horizontally or vertically while being rotated.



I've messed with bits of it, but I'm still new to these lua functions, and find that one often has to find a workaround for non-defaults. Some help with the matter would be much appreciated.

[Altair]

You could use this to mirror it (just made it, so I haven't tested it, but it should work):

-- Variables
smile = Image.load("smiley.png")
function mirrorImage(theImage)
	newImage = Image.createEmpty(theImag  e:height(), theImage:width())
	for x = theImage:width(),1,-1 do
		for y = 1, theImage:height() do
			newImage:blit(x, y, theImage, x, y, 1, 1)
		end
	end
	return newImage
end -- rotateImage

Pretty easy actually (yes I used this code as a basis).

[Altair]

I know that this is a real noob like question but:
What does the alpha channel in LUA do and how do i use it?
--Vaza

It sets the transparency. 0 is no transparency and 255 is full transparency.

[Paburo]

You could use this to mirror it (just made it, so I haven't tested it, but it should work):

*insert code here*

Pretty easy actually (yes I used this code as a basis).

Actually, it does the exact same thing as if you had only swapped the x and y in the blit function: copied the image exactly as it had been. Thanks for the attempt, though.

[Electro]

Actually, it does the exact same thing as if you had only swapped the x and y in the blit function: copied the image exactly as it had been. Thanks for the attempt, though.

i need help on doing that too,,

[zmathue]

Can any one help me I want my program to Save a irda signal to a variable on a botton press while selecting an object on a menu.
This is what I have so far:

if pad:circle() and menustatus == -1 then
irdasignal = System.irdaRead()
end

[Altair]

Actually, it does the exact same thing as if you had only swapped the x and y in the blit function: copied the image exactly as it had been. Thanks for the attempt, though.

Huh? It should work assuming that LUA starts at the last x and ends with the first one. I looked it up in the manual and LUA should be able to do that because I make it use steps of -1.
Did you try it with the yellow/purple smiley?

[Paburo]

Huh? It should work assuming that LUA starts at the last x and ends with the first one. I looked it up in the manual and LUA should be able to do that because I make it use steps of -1.
Did you try it with the yellow/purple smiley?

I wouldn't try it with any other. Implimenting the code you handed me, the image is just copied exactly.

-- Variables
smile = Image.load("smiley.png")
function mirrorImage(theImage)
	newImage = Image.createEmpty(theImage:height(), theImage:width())
	for x = theImage:width(),1,-1 do
		for y = 1, theImage:height() do
			newImage:blit(x, y, theImage, x, y, 1, 1)
		end
	end
	return newImage
end -- rotateImage
screen:blit(0, 0, smile)
screen:blit(100, 0, mirrorImage(smile))
screen:flip()
screen.waitVblankStart(600)

[Altair]

Got it I forgot that it uses the same x:

smile= Image.load("smiley.png")

function mirrorImage(theImage)
	newImage = Image.createEmpty(theImage:width(),theImage:height())
	x2=0          --second x needed otherwise it pastes the x at the same place
	for x = theImage:width(),0,-1 do
		for y = 0, theImage:height() do
			newImage:blit(x, y, theImage, x2, y, 1, 1)
		end
		x2=x2+1
	end
	return newImage
end

screen:clear()
screen:blit(0, 0, smile)
screen:blit(100, 0, mirrorImage(smile))
screen.waitVblankStart()
screen:flip()

while true do           -- this is just for testing purpose
        screen.waitVblankStart()

	pad = Controls.read()
		if pad:start() then
			break
		end
end

[Mast3r_Shak3]

Ok.. Im making a sidescroll engine and I need help with direction association with the sprites when i press left and right. Ive tested a few things but I get over lapping images... help?

[Grimfate126]

Ok.. Im making a sidescroll engine and I need help with direction association with the sprites when i press left and right. Ive tested a few things but I get over lapping images... help?

are you coding your own? or are u using my tut? OR are you using lumos code??

[Mast3r_Shak3]

Which tuts are you reffering to?

Heres my code

black = Color.new(0,0,0)

--VARIABLES/ARRAYS--
player = {}
player.x = 20
player.y = 200

enemy = {}
enemy.x = 420
enemy.y = 200

poox = nil    --poox, pooy = player poo--
pooy = nil   
poo2x = nil   --poo2x, poo2y = AI poo--
poo2y = nil 

at=1 --Air Time--
aj=0 --Active Jump--
r=0 --Ready (To Jump)--

z = 0

--IMAGES--
browndashleft = Image.load("brown/monkey1dashl.png")
browndashright = Image.load("brown/monkey1dashr.png")
brownhitleft = Image.load("brown/monkey1hitl.png")
brownhitright = Image.load("brown/monkey1hitr.png")
brownjumpleft = Image.load("brown/monkey1jumpl.png")
brownjumpright = Image.load("brown/monkey1jumpr.png")
brownstandleft = Image.load("brown/monkey1standl.png")
brownstandright = Image.load("brown/monkey1standr.png")

bluedashleft = Image.load("blue/monkey2dashl.png")
bluedashright = Image.load("blue/monkey2dashr.png")
bluehitleft = Image.load("blue/monkey2hitl.png")
bluejumpleft = Image.load("blue/monkey2jumpl.png")
bluejumpright = Image.load("blue/monkey2jumpr.png")
bluestandleft = Image.load("blue/monkey2standl.png")
bluestandright = Image.load("blue/monkey2standr.png")

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

--FUNCTIONS--
function moveleft()
   z = 1
     if player.x > 0 then
     player.x = player.x - 5
     end
end

function moveright()
   z = 2
     if player.x < 456 then
     player.x = player.x + 5
     end
end

function textbgstuff()
   screen:blit(0,0, bg, false)
   screen:print(2,2, "WiP Engine Test", black)
   screen:print(2,12, "DONE: Movement, Sprites, jumping", black)
   screen:print(2,22, "TODO: throwing, AI, collision, directional association", black)
end

function blitstuff()
   screen:blit(player.x, player.y, browndashright)
   screen:blit(enemy.x, enemy.y, bluestandleft)
end

function throw()
--being worked on--
end

function jump()
--being worked on--
end

function direction()
   if z == 1 then
      screen:blit(player.x, player.y, browndashleft)
   end
   if z == 2 then
      screen:blit(player.x, player.y, browndashright)
   end
end

function jump()
if aj==0 and math.abs(player.y) > 199 then 
   r=1 else r=0 
end

if pad:square() and r==1 then 
   aj=1 
end

if aj==1 and math.abs(at) < 100 then 
   player.y=player.y-5 
   at=at+1 
end

if at==20 then 
   aj=0 
   at=1 
end

if aj==0 and math.abs(player.y) < 200 then 
   player.y=player.y+6 
end
end

while true do  ----MAIN LOOP----

screen:clear()

textbgstuff()

pad = Controls.read() 

if pad:left() then
   moveleft()
end

if pad:right() then
   moveright()
end

direction()
jump()

if pad:start() then 
	break
end

blitstuff()

screen.flip()
screen.waitVblankStart()
end

[Grimfate126]

Which tuts are you reffering to?

Heres my code

black = Color.new(0,0,0)

--VARIABLES/ARRAYS--
player = {}
player.x = 20
player.y = 200

enemy = {}
enemy.x = 420
enemy.y = 200

poox = nil    --poox, pooy = player poo--
pooy = nil   
poo2x = nil   --poo2x, poo2y = AI poo--
poo2y = nil 

at=1 --Air Time--
aj=0 --Active Jump--
r=0 --Ready (To Jump)--

z = 0

--IMAGES--
browndashleft = Image.load("brown/monkey1dashl.png")
browndashright = Image.load("brown/monkey1dashr.png")
brownhitleft = Image.load("brown/monkey1hitl.png")
brownhitright = Image.load("brown/monkey1hitr.png")
brownjumpleft = Image.load("brown/monkey1jumpl.png")
brownjumpright = Image.load("brown/monkey1jumpr.png")
brownstandleft = Image.load("brown/monkey1standl.png")
brownstandright = Image.load("brown/monkey1standr.png")

bluedashleft = Image.load("blue/monkey2dashl.png")
bluedashright = Image.load("blue/monkey2dashr.png")
bluehitleft = Image.load("blue/monkey2hitl.png")
bluejumpleft = Image.load("blue/monkey2jumpl.png")
bluejumpright = Image.load("blue/monkey2jumpr.png")
bluestandleft = Image.load("blue/monkey2standl.png")
bluestandright = Image.load("blue/monkey2standr.png")

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

--FUNCTIONS--
function moveleft()
   z = 1
     if player.x > 0 then
     player.x = player.x - 5
     end
end

function moveright()
   z = 2
     if player.x < 456 then
     player.x = player.x + 5
     end
end

function textbgstuff()
   screen:blit(0,0, bg, false)
   screen:print(2,2, "WiP Engine Test", black)
   screen:print(2,12, "DONE: Movement, Sprites, jumping", black)
   screen:print(2,22, "TODO: throwing, AI, collision, directional association", black)
end

function blitstuff()
   screen:blit(player.x, player.y, browndashright)
   screen:blit(enemy.x, enemy.y, bluestandleft)
end

function throw()
--being worked on--
end

function jump()
--being worked on--
end

function direction()
   if z == 1 then
      screen:blit(player.x, player.y, browndashleft)
   end
   if z == 2 then
      screen:blit(player.x, player.y, browndashright)
   end
end

function jump()
if aj==0 and math.abs(player.y) > 199 then 
   r=1 else r=0 
end

if pad:square() and r==1 then 
   aj=1 
end

if aj==1 and math.abs(at) < 100 then 
   player.y=player.y-5 
   at=at+1 
end

if at==20 then 
   aj=0 
   at=1 
end

if aj==0 and math.abs(player.y) < 200 then 
   player.y=player.y+6 
end
end

while true do  ----MAIN LOOP----

screen:clear()

textbgstuff()

pad = Controls.read() 

if pad:left() then
   moveleft()
end

if pad:right() then
   moveright()
end

direction()
jump()

if pad:start() then 
	break
end

blitstuff()

screen.flip()
screen.waitVblankStart()
end

umm, how is that a sidescrolling engine??

[Mast3r_Shak3]

Well its sidescrolling... maybe im not using the right terminology... but i still need help...

[Grimfate126]

Well its sidescrolling... maybe im not using the right terminology... but i still need help...

is our background moving to the left or right automatically??

[Mast3r_Shak3]

No... okay i get it its not an engine but I still need help..........

[TheMarioKarters]

Master Shake, is that the Monkey Poo fight game you and bronx are doing?

[Mast3r_Shak3]

Yeah.

[montrob]

Are you gonna finish flipbook?

[Mast3r_Shak3]

At one point... butterballer on psp-programming said he wanted to work with me and i accepted and he said he rewrote flipbook completely... but Im gonna wait til I get back in florida to do any more work on that

[Grimfate126]

No... okay i get it its not an engine but I still need help..........

can u pm me the files wit the images?? i u want?? i can tyr to fix it. i cant see wha you mean by using words. i wont steal. i dont need to,

[zmathue]

I got two questons
1.
Can any one help me I want my program to Save a irda signal to a variable on a botton press while selecting an object on a menu.
This is what I have so far:

if pad:circle() and menustatus == -1 then
irdasignal = System.irdaRead()
end

2.
when I hit left or right my pic. doesnt move but when I hit up or down it moves .

red = Color.new(255, 0, 0);
white = Color.new(255, 255, 255);

char = Image.load("char.png")

y = 100
x = 100

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

		if pad:up() then
			y = y - 1
		elseif pad:down() then
			y = y + 1
		elseif pad:left() then
			X = x - 1
		elseif pad:right() then
			X = x + 1
		end
	screen:blit(x, y, char, 0, 0, char:width(), char:height(), true)
screen.flip()
	screen.waitVblankStart()
	if pad:start() then break end
end

[Grimfate126]

I got two questons
1.
Can any one help me I want my program to Save a irda signal to a variable on a botton press while selecting an object on a menu.
This is what I have so far:

if pad:circle() and menustatus == -1 then
irdasignal = System.irdaRead()
end

2.
when I hit left or right my pic. doesnt move but when I hit up or down it moves .

red = Color.new(255, 0, 0);
white = Color.new(255, 255, 255);

char = Image.load("char.png")

y = 100
x = 100

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

		if pad:up() then
			y = y - 1
		elseif pad:down() then
			y = y + 1
		elseif pad:left() then
			X = cx - 1
		elseif pad:right() then
			X = cx + 1
		end
	screen:blit(x, y, char, 0, 0, char:width(), char:height(), true)
screen.flip()
	screen.waitVblankStart()
	if pad:start() then break end
end

i dont know aboyut the first question, but in the second one, have you defined cx?? or did you men to put just "x"?

[zmathue]

I changed them to that to see if it was my variable that was the problem I guess I forgot to change it back to x when I posted.
^^i fixed the thred now^^