Lua Programming Help Thread

[TacticalPenguin]

if collision(something,somet hing) then if player.img == something then dosomething else dofile("br.lua") end end

[Urameshi]

that didnt work

[SG57]

What do you mean by 'the player iamge is different'? If your talking about a powerup for invincibility or shield, use a bool/flag.

if collide(player,object) and shield_on == false then dofile("w/ethisscriptis.lua") end

[Urameshi]

can you explain what that shield_on thing is

[xpack]

What do you mean by 'the player iamge is different'? If your talking about a powerup for invincibility or shield, use a bool/flag.

if collide(player,object) and shield_on == false then dofile("w/ethisscriptis.lua") end

can you explain what that shield_on thing is

The shield_on is suppose to be a powerup and if the player and object collide without a shield then it will do a certain file, then you can just add something like if the player and object collide then the player just bounces or whatever away

[radioactive_X]

the image is 50x50 pixels, however because the coord system starts at 0, the for loop should only go to 49

Thank you very much.

I knew it was something stupid, I just didn't think about that since it worked with a loaded image.

[eldiablov]

please can someone give me the collison formula :Argh:

[Merick]

Here's the formula from the collision function I'm currently using, I got it from Yaustar's C circle collision function that he posted on Evilmana:

   distanceSquared = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)
   radiusSquared = (rad2 + rad1) * (rad2 + rad1)
   
   if distanceSquared < radiusSquared then
      return true
   else
      return false 
   end

x1,y1 and x2,y2 are the center points of each object image in relation to the screen

rad1 and rad2 are the radius to use for each object, in my version I have it setup to automatically calculate these to be half of whichever side of the object image is the shortest

[eldiablov]

you misunderstood me. I meant ...

Wait i'll quote myself from the previous posts.

Omg i still cant find the post. Anyway it was basiclally that when the player hits the ball the ball goes away at the angle the player came from and then slow down due to friction.

[Merick]

well, you could try something like this :

xspeed = 5, (or whatever)
yspeed = 7
(current speed at which the player is moving)

after collision, you would change the ball position each cycle like this:

ballspeed = 5
ball.x = ball.x + (xspeed * ballspeed)
ball.y = ball.y + (yspeed * ballspeed)
ballspeed = ballspeed - .3 (or whatever)
if ballspeed <=0 then ball stops

[yaustar]

you misunderstood me. I meant ...

Wait i'll quote myself from the previous posts.

Omg i still cant find the post. Anyway it was basiclally that when the player hits the ball the ball goes away at the angle the player came from and then slow down due to friction.

Done: http://www.gamasutra.com/features/20...lander_pfv.htm

[eldiablov]

ok yaustar. I'l try that when i get home because that sites blocked on this computer.
-= Double Post =-
BAH now my head hurts again. These formulas aren't at all simple :Argh:

[ahrimanes]

i have downloades TTlde 2.1 and wen im traying to run it i ever got this error
error: ttlde.lua:10: module 'pad.lc' not found:
no field package.preload['pad.lc']
no file './pad/lc.lua'
no file '/usr/local/share/lua/5.1/pad/lc.lua'
no file '/usr/local/share/lua/5.1/pad/lc/init.lua'
no file '/usr/local/lib/lua/5.1/pad/lc.lua'
no file '/usr/local/lib/lua/5.1/pad/lc/init.lua'
no file './pad/lc.so'
no file '/usr/local/lib/lua/5.1/pad/lc.so'
no file '/usr/local/lib/lua/5.1/loadall.so'
no file './pad.so'
no file '/usr/local/lib/lua/5.1/pad.so'
no file '/usr/local/lib/lua/5.1/loadall.so'
can some one tell me hor to make this works.. this hapen on lpwindows. and psp
my psp is 3.10 oe a'

[cruisx]

hi i am useing PSP Game Maker v 0.7 but i have a prob. I need to kno where to put my files, like my pic and sound filkes where do i put them? pls help =)

[Bob Hoil]

Just put them in the same directory as the lua script file that uses them.

[ahrimanes]

please can someone give me the collison formula :Argh:

Omg i still cant find the post. Anyway it was basiclally that when the player hits the ball the ball goes away at the angle the player came from and then slow down due to friction.

it might help you.

if colide(player,ball) then
   ball.angle = player.angle
   ball.speed = player.shutpawer
end if

in your ballupdate function use:

function updateball()
   ball.x = ball.x + math.sin(ball.angle)*ball.speed
   ball.y = ball.y + math.cos(ball.angle)*ball.speed
   if ball.speed > 0 then
      ball.speed = ball.speed-friction --the ball continues and lose speed.
   else
      ball.speed = 0 --the ball stops
   end
end

i think this culd help you.. when i do somthing whit angle i thibk is betther to calculate the next x y whit sin cos angle * speed. this is good.. now you just need to see the limist of the x and y i think you can figure out how to do that. else. fell fre to ask. im glad of helping.....by the wai i write this code here it might have some errors. but tis the logic what you need.

[cruisx]

um can someone help me with my code

red = Color.new(255, 0, 0)
background = Image.load("images/background.jpg")
screenrint(200, 100, "Look! I made text appear!", red)
screen.flip()
while true do
screen.waitVblankStart()
end

i cant get the image to load. Its my first time codeing so i dont kno wats wrong. Can someone pls help me.

[PSPJunkie_]

You never blit the image. I'm sure it loads, though.

red = Color.new(255, 0, 0)
background = Image.load("./images/background.jpg")
while true do
     screen:clear(Color.new(0, 0, 0)) --may be wrong function name :|
     screen:blit(0, 0, background, true)
     screen:print(200, 100, "Look! I made text appear!", red)
     screen.waitVblankStart()
     screen.flip()
end

[Urameshi]

um can someone help me with my code

red = Color.new(255, 0, 0)
background = Image.load("images/background.jpg")
screenrint(200, 100, "Look! I made text appear!", red)
screen.flip()
while true do
screen.waitVblankStart()
end

i cant get the image to load. Its my first time codeing so i dont kno wats wrong. Can someone pls help me.

red=Color.new(255,0,0)
background=Image.load("./images/background.jpg")

while true do
screen:clear()

screen:blit(0,0,background)
screen:print(200, 100, "Look! I made text appear!", red)

screen.waitVblankStart()
screen.flip()
end

[PSPJunkie_]

You never blit the image. I'm sure it loads, though.

red = Color.new(255, 0, 0)
background = Image.load("./images/background.jpg")
while true do
     screen:clear(Color.new(0, 0, 0)) --may be wrong function name :|
     screen:blit(0, 0, background, true)
     screenrint(200, 100, "Look! I made text appear!", red)
     screen.waitVblankStart()
     screen.flip()
end

.......

red=Color.new(255,0,0)
background=Image.load("./images/background.jpg")

while true do
screen:clear()

screen:blit(0,0,background)
screen:print(200, 100, "Look! I made text appear!", red)

screen.waitVblankStart()
screen.flip()
end

????

[romulator]

At least Urameshi's code works. You didn't even check yours lol.

[eldiablov]

it might help you.

if colide(player,ball) then
   ball.angle = player.angle
   ball.speed = player.shutpawer
end if

in your ballupdate function use:

function updateball()
   ball.x = ball.x + math.sin(ball.angle)*ball.speed
   ball.y = ball.y + math.cos(ball.angle)*ball.speed
   if ball.speed > 0 then
      ball.speed = ball.speed-friction --the ball continues and lose speed.
   else
      ball.speed = 0 --the ball stops
   end
end

i think this culd help you.. when i do somthing whit angle i thibk is betther to calculate the next x y whit sin cos angle * speed. this is good.. now you just need to see the limist of the x and y i think you can figure out how to do that. else. fell fre to ask. im glad of helping.....by the wai i write this code here it might have some errors. but tis the logic what you need.

Thank you soooo much

But where do you define ballpower?

[PSPJunkie_]

At least Urameshi's code works. You didn't even check yours lol.

And? It was the exact same thing... @[email protected]

[ahrimanes]

Thank you soooo much

But where do you define ballpower?

there is not ball power. just ball speed, that increases when the player touch it, and decreaces by friction every loop.
i mybe worng calling.. ball.speed = player.shutpawer... i must bee
ball.speed = player.pushforce.. since is not theplayer shuting the ball but driving it..well any question are wellcome .

[emericaska8r]

eldiablov:

when the ball collides (with another ball), make sure the angle you give it isn't just player.angle.
that will only work if the collide straight on. If you hit it at more of an angle, you will need some formula for that. If you need help with that, i could figure it out later.
-= Double Post =-
lol, i kind of want to make a pool game now.

[ahrimanes]

he is making a soccer game, i dont think he need ball colision formula :)

[emericaska8r]

lol my bad, i thought he was making a pool game, sorry. :o

[ahrimanes]

lol, i kind of want to make a pool game now.

if you still want to do the pool game i have a ball collide script i made in blitzmax. it will be easy to port to lua. if you wanna try ...tell.....

[cruisx]

You know how you can move back and forth through pics in the psp XMB by pressing R and L. Well is their any way to do this in lua? like by pressing R u go to the next pick and pressing L u go back to the previous pic?

[emericaska8r]

sure ahrimanes, thanks.