Lua Programming Help Thread

[EminentJonFrost]

if timer:time() > 0 < 1000 then
x = x - 1
end

should be:

if timer:time() > 0 and timer:time() < 1000 then
x = x - 1
end

[myschoo]

hmm its still doesnt make that effect -_- never mind and thx

[HeaD_ShOt]

could someone show me an example of moving an object halfway across the screen from left to right
all your help is much appreciated
thanks

[Anti-QuickJay]

Like as we control it or it justs moves on its own?

[HeaD_ShOt]

on its own

[EminentJonFrost]

on its own

um...a simple example is:

while true do
if object.x < destination.x and object.status == hasnt_reached_destination_yet then
object.x = object.x + 1
elseif object.x >= destination.x or object.status ~= hasnt_reached_destination_yet then
object.x = object.x - 1
object.status = destination_reached
end
end

is it understandable?

[xtreme0915]

xtreme - I posted an example that uses a timer, and does just waht you want. Timers arent confusing either, just think logically....

I just started and im only in the ninth grade, but i am looking to become a programer so if figured i my as well start trying, so well that's gone

[EminentJonFrost]

I just started and im only in the ninth grade, but i am looking to become a programer so if figured i my as well start trying, so well that's gone

lol
ninth grade isnt very special around these parts. there are some amazing youngsters out there...(not me, i wish )

[SG57]

xtreme - Im in 9th gradetoo, so thats no excuse. If I can handle the simple logicallness that is 'a timer' I think you can too...

[Anti-QuickJay]

It doesn't matter what grade your in.

[xtreme0915]

wow, that hurts, lol, looks like i got some research ahead of me

[Hedzx]

im in 9th grade >_>...
i need help..
how would you be able to check if a file was there, and if it is, return as eighter true or false? (if possible, i think it is)

[HeaD_ShOt]

only...

btw
there is a sample script for this at Evilmana

[Hedzx]

only...

btw
there is a sample script for this at Evilmana

for timers or checking if a file is there?

[HeaD_ShOt]

timers

-- EVILMANA.COM PSP LUA CODEBASE
-- www.evilmana.com/tutorials/codebase
-- Game Timer
-- SUBMITTED BY: dtodabreezy
red=Color.new(255,0,0)
black=Color.new(0,0,0)

--i like this font becuz it dosent get in the way

proportional = Font.createProportional()
proportional:setPixelSize s(0,25)


--time for game
gametimer=Timer.new()
time=60
gametimer:start()



while true do
--gets time
gamestime=gametimer:time( )
-- take this out to use in game
screen:clear(black)

--tells it count down 1 second every second
if gamestime>1000 then time=time - 1 gametimer:reset(0) gametimer:start()
end

screen:fontPrint(proporti onal, 220, 25, time, red)

link

[SG57]

yauster - I know, but I was porting it, and was hoping to gainevery aspect of the PC version. But, seeing theactual mechanics of a particle engine such as this, Im going to write my own. That way, I learn something :)

I have all evening to do it, so hopefully you could look over my code later on for optimization tricks :o Also, Ill be making it visually better, as in using either small textured quads OR simply pixels (ill need alot of particles if i use pixels). (im trying to say i understand the mechanics of atleast one type of particle engine and now i believe ican write my own)...

itll probably look the same as some others in many aspects, but honestly, itll be my own, whether or not you believe me doesnt matter to me too much...

*starts individual particle structure*
-= Double Post =-
Im confused on the question being asked but...

if io.open("file.extension","r") then
--file exists
else
--file doesnt exist
end

[Hedzx]

yauster - I know, but I was porting it, and was hoping to gainevery aspect of the PC version. But, seeing theactual mechanics of a particle engine such as this, Im going to write my own. That way, I learn something :)

I have all evening to do it, so hopefully you could look over my code later on for optimization tricks :o Also, Ill be making it visually better, as in using either small textured quads OR simply pixels (ill need alot of particles if i use pixels). (im trying to say i understand the mechanics of atleast one type of particle engine and now i believe ican write my own)...

itll probably look the same as some others in many aspects, but honestly, itll be my own, whether or not you believe me doesnt matter to me too much...

*starts individual particle structure*
-= Double Post =-
Im confused on the question being asked but...

if io.open("file.extension","r") then
--file exists
else
--file doesnt exist
end

yeah thats perfect thanks

[xtreme0915]

ok you guys i really want to get this, if i have

timer = Timer.new()
timer:start()

while true do
     screen:clear()

     screen:print(208,131,"Checking flash0",red)

     if timer:time() >= 1000 and timer:time() < 2000 then
       screen:print(272,131,".",red)
     elseif timer:time() >= 2000 and timer:time() < 3000 then
       screen:print(272,131,"..",red)
     elseif timer:time() >= 3000 and timer:time() < 4000 then
       screen:print(272,131,"...",red)
     elseif timer:time() >= 4000 then

how can i make it end after going through once and begin another timer? sorry for so many questions but i am really trying

[PSPhakkor]

didn't I post before that rather than starting another timer, you could just use math.floor(timer:time()/1000)=2

I think I did but Im too lazy to check so yeah there ya go. If you really want it to be another timer, then you could use Timer:reset([startTime]) and then restart the timer.

[SG57]

yauster - I have all the basics sofar, now I just need to set a random x and y coordinate plane speed... I have to do some research on google, but if you get this before i do, please post a way (i have an angle of direction set up, 0-360 as i want it to be in a circle, randomly set each time the particle dies).

xtreme - You arent thinking logically, there fore you lose... If you wantto start another timer when a certain timer reaches a certain time, you do..

timer1 = Timer.new()
timer2 = Timer.new()

timer1:start()

while true do
     if timer1:time()  > 10000 then 
         timer1:stop()
         timer2:start()
     end
end

[xtreme0915]

oh, haha, thanks, today i have done a little more research and discovered a little more.

http://files.filefront.com//;6652077;;/

what do you think?

**NOTE** when the screen is black you must press a button to begin

[SG57]

I dont have a PSP, so I cant really do much enjoyable...

Anywho...

Ive finished my particle engine. Im going to debug it now and fix any syntax errors, then ill upload it. Hopefully someone can test it and tellme what they tink...

[BlackShark]

Ill test if you want SG

[SG57]

Alright guys, i made this particle engine, using prior PD experience, but sure enough, i typed it up and only had to research on one part for 1 minute... In the end, i came up with this... please test it someone and if you can,video tape it as eyece has done ;)

--[[
     Lua Particle Demo
         By: SG57


     No more than an
      eye looker...
        For now ;)
]]

num_particles = 299 -- # of particles to have on screen
particle = {}

for i=0,num_particles do  -- constructs each particle with default values
       particle[i] = { x=240,y=136,                   -- x and y coordinates
                       xspeed,yspeed,                -- speed on x and y planes
                       color=Color.new(255,255,255), -- color of particle
                       life=0,                       -- life determines color ^
                       angle=math.random(360),       -- random angle for particle movement
                       speed=10,                      -- particle speed
                       fade_speed=20,  -- fading speed of particle
                       r=255,g=255,b=255             -- so color can be changed
                     }
       particle[i].xspeed = math.sin(particle[i].angle) * particle[i].speed -- set x axis vector speed
       particle[i].yspeed = math.cos(particle[i].angle) * particle[i].speed -- set y axis vector speed
end

while true do
   screen:clear()
   for i=0,num_particles do
       particle[i].xspeed = math.sin(particle[i].angle) * particle[i].speed -- set x axis vector speed
       particle[i].yspeed = math.cos(particle[i].angle) * particle[i].speed -- set y axis vector speed

       particle[i].x = particle[i].x + particle[i].xspeed -- Vector speeds
       particle[i].y = particle[i].y + particle[i].yspeed -- ^

       particle[i].color = Color.new(particle[i].r,particle[i].g,particle[i].b,particle[i].life)

       if particle[i].life >= 255 then
            particle[i].r=math.random(255)
            particle[i].g=math.random(255)
            particle[i].b=math.random(255)
            particle[i].life = 0
            particle[i].speed=math.random(1,3)
            particle[i].fade_speed=math.random(7,9)
            particle[i].x = 240
            particle[i].y = 136
            particle[i].angle=math.random(360)
       end

       particle[i].life = particle[i].life + particle[i].fade_speed

       screen:fillRect(particle[i].x,particle[i].y,2,2,particle[i].color)
   end

   screen.waitVblankStart()
   screen.flip()
end

[Anti-QuickJay]

It runs pretty smooth on the PSP.
I cant get to a camera but maybe later unless someone else does it.

[SG57]

Im not to worried about framerate, rather the look of it. Id like to know what you think it looks like... A fire, a bomb, etc.?

[Anti-QuickJay]

It looks more like an explosion, Like at the middle you see all the clolors, Then it just spreads out. Its really smooth so it looks really kool on the PSP.

[SG57]

Wait, so it explodes, the colors spread across screen, then it explodes again? Im aiming for a smooth constant flame type thing - easily fixable. But Im going to port this code to VB 6.0 so i can see it correctly. and modify it appropriatly.

Oh and also - do the explosion particles fade away atall? or just scatter of screen? Id really like a video someone Cant you get the screen capture module thing shrrom? You just press R+SELECT i believe to take a video fo wahtever is on the screen...

[Anti-QuickJay]

Ok, I will downlaod SVC, But it explodes at first like in a circle motion, Then it starts to spread out from the middle, But it doesnt look like they fade away, They just disappear.

[SG57]

Ahh.. ok. And yes, it should explode ina circle motion, than it should just act as a fire or a smoke type effect... Once you get the video thing uploaded, ll be able to really see what i can do to improve it. Also, make sure you use that trick to compress the GIF and whatnot... That way, its not like 30 mb.