Lua Programming Help Thread

[Gonrai]

Okay, heres my code:

-- Alien Crosshair Game Screen
-- Completally Coded by Mailas Gonrai
-- Most errors fixed by pjspeedy and yaustar
-- Colors
black = Color.new(0,0,0)
blue = Color.new(191, 255, 195)
yellow = Color.new(255, 255, 0, 200)
green=Color.new(0,255,0, 195)
white = Color.new(255,255,255)
red = Color.new(255,69,0, 195)

-- ETC Variables
displayTime = math.random(2,5)
counter = 0
speed = 1
offscreen = false
pad = Controls.read()
-- Functions
function RandomPoint()
end
math.randomseed(os.time())

-- Images
back = Image.load("./Images/back_game.png")
crosshair = Image.load("./Images/crosshair.png")
border = Image.load("./Images/game_border.png")
alienimage = Image.load("./Images/alien.png")

-- Music
Music.playFile("./Music/grmus.it")

-- Objects
Player = {}
Player.x = 208
Player.y = 112

alien = {}
alien.x = math.random(1,3)
alien.y = math.random (1,3)
alien = {x = 0, y = 200}
x_point = 23
y_point = 83

-- Health Equivelent Options
Player.health = 100
healthbar = {}
healthbar.y = 10


function movePlayer()
	if pad:left() then
		Player.x = Player.x - 4
	end

	if pad:right() then
		Player.x = Player.x + 4
	end
	
	if pad:down() then
		Player.y = Player.y + 4
	end

	if pad:up() then
		Player.y = Player.y - 4
	end
end

function perimeterSize()
	if Player.x > 480 - 64 then
		Player.x = 480 - 64
	end
	
	if Player.x < 0 then
		Player.x = 0
	end

	if Player.y > 272 - 64 then
		Player.y = 272 - 64
	end
	
	if Player.y < 0 then
		Player.y = 0
	end
end



-- THE LOOP!----------------------------------------------------------

while true do

	screen:clear()
	x_point = math.random(1,480)
y_point = math.random(1,272)
AlienMove()

        if alien.x < x_point then
alien.x = alien.x + 2
end
if alien.x > x_point then
alien.x = alien.x - 2
end
if alien.y < y_point then
alien.y = alien.y + 2
end
if alien.y < y_point then
alien.y = alien.y - 2
end
if alien.x == x_point and alien.y == y_point then
RandomPoint()
end
					
		
		counter = counter + 1
	
		if counter >= displayTime then
			alien.x = math.random(1,3)
			alien.y = math.random (1,3)
				end
	
		if alien.x == 1 then
			alien.x = 224
			alien.y = 182
		end
	
		if alien.x == 2 then
			alien.x = 60
			alien.y = 132
		end
	
		if alien.x == 3 then
			alien.x = 404
			alien.y = 154
		end
	
			
		displayTime = math.random(500,2000)
		counter = 0
	end
	
	screen:blit(0,0,back)
                    screen:blit(alien.x,alien.y,alienimage)	
                    screen:blit(Player.x,Player.y,crosshair)
	screen:blit(0,0,border)
	
	screen:fillRect(320,240,Player.health,healthbar.y,green)
	screen:print(320,230,Player.health,blue)
	
	movePlayer()
	perimeterSize()
	alienscreenSize()
	
	if pad:l() then
		dofile("menu.lua")
	end

	screen.waitVblankStart()
	screen.flip()
end

And my error:

error: ./game.lua:159: /<eof>/ expected near /end/

[TheEmulatorGuy]

displayTime = math.random(500,2000)
counter = 0
end

The 'end' there is messing your script up. Remove it.

[SG57]

Technically, its the end at the very end. Putting that mis-placed end where he does have it, closes the main loop, and until something breaks it, everything beyond it is useless... Removing hte ending end would also solve it ;) Just not how you would want it.

[TheEmulatorGuy]

Technically, its the end at the very end. Putting that mis-placed end where he does have it, closes the main loop, and until something breaks it, everything beyond it is useless... Removing hte ending end would also solve it ;) Just not how you would want it.

Yes, I assumed he wanted a solution that would help him.

[altunozara]

Could anyone tell me how to make it so...in the end of your code when if it sais like..press x how do i make it read another text document...


so how do i make it read another text thing after i press abuton...code please =-)

[SG57]

dofile("path.lua")

[LMelior]

@ Gonrai
If you wanted you could improve your code's efficiency by combining the functions movePlayer() and perimeterSize() like this:

function movePlayer()
	if pad:left() and Player.x > 0 then
		Player.x = Player.x - 4
	end

	if pad:right() and Player.x < 480 - 64 then
		Player.x = Player.x + 4
	end
	
	if pad:down() and Player.y < 272 - 64 then
		Player.y = Player.y + 4
	end

	if pad:up() and Player.y > 0 then
		Player.y = Player.y - 4
	end
end

It's a small improvement, sure, but if your project becomes large, it's the little things like this that you have to watch for and improve.


@ altunozara

file=io.open("yourfile.txt","r")
documenttext=file:read("*a")
file:close()

The variable "documenttext" will be one long string containing all of the characters in your text file, including possibly the character representations of escape sequences. Be aware that unless your file is essentially one line (e.g. you didn't press Enter while you were making the text file), you may have some funky characters like that.

[hallo007]

is it possible to clear some part of the screen and not everything

[Glynnder]

I think it is, but i forgot how.

[Gonrai]

Heres what I did:
I looked at what emulator guy said and was kinda confused because
1. the math.random on displayTime is 2,5, not 200,5000
2. There is no end under the counter variable.

THen, I looked at SG57's post and I removed the end so it looks like this:

if pad:l() then
		dofile("menu.lua")
	end

	screen.waitVblankStart()
	screen.flip()

At the end of my script. But heres what happened:
When I loaded my game on my menu script, it just froze.

[LMelior]

@hallo007

is it possible to clear some part of the screen and not everything

I'm not sure what you mean...just stop blitting whatever it is to screen? But you could always cheat and make a rectangle to cover up part of the screen.

coverup=Image.createEmpty(240,272)
screen:blit(0,0,coverup)

To cover up the left half. Many coders use a separate image variable that they "build up" and then they only have to blit that to screen. I call mine "prescreen" but you may have seen "offscreen" in some codes:

prescreen=Image.createEmpty(480,272)
-- (blit everything to prescreen)
coverup=Image.createEmpty(240,272)
prescreen:blit(0,0,coverup)
screen:blit(0,0,prescreen)

I've been told this is faster than blitting everything directly to the screen buffer, though I've never actually tested this. It just seems cleaner so I always do it.



@ Gonrai

2. There is no end under the counter variable.

Direct from your post above (with indentations left in):

		displayTime = math.random(500,2000)
		counter = 0
	end

Sure looks like it to me, and besides SG57 even told you that it wouldn't work (he teases Lua coders for kicks ).

[xsorifc28]

index.lua:2: error loading sound? help?!
edit. heres the code
iyk = Sound.load("iyk.wav")
iyklay()
Music.volume(128)

[Glynnder]

actually, that presreen thing will use more RAM and be slower, because it has to create the image

[xsorifc28]

index.lua:2: error loading sound? help?!
edit. heres the code
iyk = Sound.load("iyk.wav")
iyklay()
Music.volume(128)

i dont get it. why am i getting an error?

[Gonrai]

My code:

-- Alien Crosshair Game Screen
-- Completally Coded by Mailas Gonrai
-- Most errors fixed by pjspeedy and yaustar
-- Colors
black = Color.new(0,0,0)
blue = Color.new(191, 255, 195)
yellow = Color.new(255, 255, 0, 200)
green=Color.new(0,255,0, 195)
white = Color.new(255,255,255)
red = Color.new(255,69,0, 195)

-- ETC Variables
displayTime = math.random(2,5)
counter = 0
speed = 1
offscreen = false
pad = Controls.read()
-- Functions
function RandomPoint()
end
math.randomseed(os.time())

-- Images
back = Image.load("./Images/back_game.png")
crosshair = Image.load("./Images/crosshair.png")
border = Image.load("./Images/game_border.png")
alienimage = Image.load("./Images/alien.png")

-- Music
Music.playFile("./Music/grmus.it")

-- Objects
Player = {}
Player.x = 208
Player.y = 112

alien = {}
alien.x = math.random(1,3)
alien.y = math.random (1,3)
alien = {x = 0, y = 200}
x_point = 23
y_point = 83

-- Health Equivelent Options
Player.health = 100
healthbar = {}
healthbar.y = 10


function movePlayer()
	if pad:left() then
		Player.x = Player.x - 4
	end

	if pad:right() then
		Player.x = Player.x + 4
	end
	
	if pad:down() then
		Player.y = Player.y + 4
	end

	if pad:up() then
		Player.y = Player.y - 4
	end
end

function perimeterSize()
	if Player.x > 480 - 64 then
		Player.x = 480 - 64
	end
	
	if Player.x < 0 then
		Player.x = 0
	end

	if Player.y > 272 - 64 then
		Player.y = 272 - 64
	end
	
	if Player.y < 0 then
		Player.y = 0
	end
end



-- THE LOOP!----------------------------------------------------------

while true do

	screen:clear()
	x_point = math.random(1,480)
y_point = math.random(1,272)
AlienMove()

        if alien.x < x_point then
alien.x = alien.x + 2
end
if alien.x > x_point then
alien.x = alien.x - 2
end
if alien.y < y_point then
alien.y = alien.y + 2
end
if alien.y < y_point then
alien.y = alien.y - 2
end
if alien.x == x_point and alien.y == y_point then
RandomPoint()
end
					
		
		counter = counter + 1
	
		if counter >= displayTime then
			alien.x = math.random(1,3)
			alien.y = math.random (1,3)
				end
	
		if alien.x == 1 then
			alien.x = 224
			alien.y = 182
		end
	
		if alien.x == 2 then
			alien.x = 60
			alien.y = 132
		end
	
		if alien.x == 3 then
			alien.x = 404
			alien.y = 154
		end
	
			
		
	screen:blit(0,0,back)
                    screen:blit(alien.x,alien.y,alienimage)	
                    screen:blit(Player.x,Player.y,crosshair)
	screen:blit(0,0,border)
	
	screen:fillRect(320,240,Player.health,healthbar.y,green)
	screen:print(320,230,Player.health,blue)
	
	movePlayer()
	perimeterSize()
	alienscreenSize()
	
	if pad:l() then
		dofile("menu.lua")
	end

	screen.waitVblankStart()
	screen.flip()
end

It now gives me this error:

error: ./game.lua:95: attempt to call a global /ALienMove/ ( a nil value)
Error: No script file found.
Press start to Restart.

[JoeDaStudd]

Alienmove isnt classed as a function
-= Double Post =-
You never did function Alienmove()
You just did Alienmove()
-= Double Post =-

i dont get it. why am i getting an error?

Have you checked that the sound file is not too big or too long for Lua Player

[jamz1825]

ok heres the deal..

i need some code to make my character shoot a bullet at wherever my crosshair image is. ive tried ALOT and cant get anything working

my character scrolls left to right at the bottom of my screen. The crosshair can go anywhere by using the directional buttons.

so could someone tell me how to do this?

[Gonrai]

jamz:
http://www.evilmana.com/tutorials/lu...et_bullets.php

[jamz1825]

trust me ive studied that, it just shoots them left right up or down


i need mine to shhot to wherever the crosshair is (that could be any x,y position)

[Glynnder]

make the cross hairs position x and y.

Then just have the bullets final location as X and Y

[jamz1825]

if you look at the evil mana tut its not as easy as just changing some xy positions

he has it set up diferent

[Twenty 2]

jamz:
http://www.evilmana.com/tutorials/lu...et_bullets.php

Sorry i dont have time to read all of your code but do you have a Controls.read(); at all to intialize the buttons?

Edit: nvm found it

[xsorifc28]

Have you checked that the sound file is not too big or too long for Lua Player

size is 450kb...its like 15-20 secs long.

[Grimfate126]

can someone pleas post a snippet to find ur current FPS???

[Shadox75]

I wanted to add a typewriter effect but I get an error.

 -- EVILMANA.COM PSP LUA CODEBASE
-- www.evilmana.com/tutorials/codebase
-- Typewriter Effect for Text
-- SUBMITTED BY: dennis van den broek

-- Code : DS (dialogue system)
-- Autor: Dennis van den broek

white = Color.new(255, 255, 255)

-- initialise if the DS (dialogue system) should be called
DS_set = 0

-- strings used for the effect
DS_str = { }
DS_str[1] = "This is a typewriter machine test..."
DS_str[2] = "This code is a test which can be used freely,"
DS_str[3] = "in any type of game, credits are allways welcome"

-- temp string that stores the current to write string
write_str = ""
str_length = 0
-- counter for holding where on the string we are
i = 1
num = 1

-- sets the DS on or off
function init_DS(type)
        if type == 1 then
                DS_set = 1
        else
                DS_set = 0
                num = 1
        end
end

-- checks what string to write, function should be upgraded with detection of which
string to print
-- currently it's a simple placeholding code
function set_DS()
        if num > 3 then
                init_DS(0)
        end
        
        Typewriter(DS_str[num], 2, 10, 100)
end

-- the actual code, input the string you wanna print, and how many characters per
frame you wanna show up...
function Typewriter(str, speed, DSx, DSy)
        read_str = str
        str_length = string.len(read_str)
        
        if i <= str_length then
                i = i+speed
                write_str = string.sub(read_str, 1, i)

                screen:print(DSx, DSy, write_str, white)
        else
                screen:print(DSx, DSy, write_str, white)
                if pad:cross() and oldpad:cross() ~= pad:cross() then
                        i = 0
                        num = num + 1
                end
        end
end

-- main while loop
while true do
        pad = Controls.read()

        if pad:cross() and oldpad:cross() ~= pad:cross() then
                init_DS(1)
        end
        
        if DS_set == 1 then
                set_DS()
        end

        screen.waitVblankStart()
        screen.flip()

        screen:clear()
        oldpad = pad
end

[SG57]

how about you post the error... Why wouldnt you saying you need help?

And I dont have time to read through the code and see whats wrong, even with an the error, but I can say having any 'screen' calls after you flip the display buffer is pointless. remove the screen:clear, it has no effect.

[Shadox75]

I get this error.

 Error: index.lua:38 /=/ expected near /to/

[SG57]

Well, go to line 38, see if there is something there that shouldnt be... Looks to me that the comment got brought out of the -- segment, making an error... Simply add '--' before 'string' on line 38.

[LMelior]

And on all of the other lines where comments are.

[Shadox75]

Ok I got it to work. Now If I want to exit my program, do I just input

 if pad:start() then 
exit