Lua Programming Help Thread

What is a nil value in LUA.
Sorry I am still learning LUA

Can someone also give me an example of how to load a ttf font and display it also.

im trying to make a maze in lua.. like a oldschool one.. like this
http://sinai.critter.net/gallery/blakat-maze.gif

i would like to have the joystick be a image.. and i would like to make it detect when i hit a black line on the maze.. whats the best way to go about that? thanks for your help!

Code:

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function check(dummy)
if dummybb[1].x + 49 >= house1x and dummybb[1].x + 49 <= house1x + 21 and dummybb[1].y + 20 >= house1y and dummybb[1].y <= house1y + 20 and tile1show1a == 1 then
dummybb[1].go = false
tile1show1a = 2
end
if tile1show1a >= 2 then
screen:fillRect(house1x, house1y, 21, 21, blue)
screen:blit(house1x, house1y, house1R)
end

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I think its either one of two things.

Code:

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function check(dummy) -- nowhere in your function does it mention "dummy" again

---

and/or

Code:

---

tile1show1a = 2
end
if tile1show1a >= 2 then -- turn ">=" into "=="
screen:fillRect(house1x, house1y, 21, 21, blue)
screen:blit(house1x, house1y, house1R)

---

Zitat:

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Zitat von EminentJonFrost

Code:

---

function check(dummy)
if dummybb[1].x + 49 >= house1x and dummybb[1].x + 49 <= house1x + 21 and dummybb[1].y + 20 >= house1y and dummybb[1].y <= house1y + 20 and tile1show1a == 1 then
dummybb[1].go = false
tile1show1a = 2
end
if tile1show1a >= 2 then
screen:fillRect(house1x, house1y, 21, 21, blue)
screen:blit(house1x, house1y, house1R)
end

---

I think its either one of two things.

Code:

---

function check(dummy) -- nowhere in your function does it mention "dummy" again

---

and/or

Code:

---

tile1show1a = 2
end
if tile1show1a >= 2 then -- turn ">=" into "=="
screen:fillRect(house1x, house1y, 21, 21, blue)
screen:blit(house1x, house1y, house1R)

---

---

Its def. not the second part.

I tried something and now i get

Code:

---

error:attempt to index field '?' <a nil value>

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anyone know what that means?

Zitat:

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Zitat von cwirsing

What is a nil value in LUA.
Sorry I am still learning LUA

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A nil value is a variable that you haven't declared yet. Example:

Code:

---

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

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

if pad:up() then
bob = bob + 1 --This would return an error saying that the program is trying --to execute an arthimetic function on a nil value.
end

screen.waitVblankStart()
screen.flip()
end

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You haven't declared bob yet, if you put bob = 1 above while true do, you declared it and the program can perform functions on it.
--PSPduh

Also, nil means that is has no value at all, nothing.

Who unstickied this?

Zitat:

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Zitat von PopcOrn DeVil

Who unstickied this?

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As you might see, there is a thread called "Programming help" which is stickied, the "Lua help thread" is linked from there.
http://forums.qj.net/psp-development-forum/53689-new-developers-read.html

Zitat:

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Zitat von PopcOrn DeVil

Who unstickied this?

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yeah, this is all serideths doing ;)