Shadowblitz16 [Lexaloffle Blog Feed]

Rounding errors when lerping towards point

Sat, 07 Mar 2020 22:26:57 UTC

can someone tell me why this always fails?
it isn't garenteed to always reach 63,63 even through i floor it.

function main()
    domain=true

    while domain do
     cls()
        spr(16,4,0,15,2)

        for i=0,8 do star() end
        yield()

    end
end

function star()
 dostar=true
 inst  =
 {
  sx=rnd(127),
  sy=127,
  ex=63,
  ey=63,
 }

    while dostar do
        local dx=flr(inst.sx)==flr(inst.ex)
        local dy=flr(inst.sy)==flr(inst.ey)
        rectfill(0,0,127,24,0)
        print(tostr(dx)..","..tostr(dy),0,0,7)
        if dx and dy then   
            dostar=false
        else
         pset (inst.sx,inst.sy,7)
         print(flr(inst.sx).."/"..flr(inst.ex),0,8,7)
         print(flr(inst.sy).."/"..flr(inst.ey),0,16,7)
            inst.sx+=(inst.ex-inst.sx)*mainstarspd
            inst.sy+=(inst.ey-inst.sy)*mainstarspd
        end
        yield()
    end
end

await function

Sun, 23 Feb 2020 01:32:06 UTC

is it possible to create a await function?

for example..

if await(60,"my identifer") then
 --done
end

here is my code

function await(t,id)
  if not cofun[id] then
    --don't know how to return true here
    add(cofun,cocreate(function()
      while t>0 do
        t-=1
    yield()
      end
    end))
  else
   return false
  end   
end

function coupdate()
 for c in all(cofun) do
  if costatus(c) then
    coresume(c)
  else
    del(cofun,c)
  end
 end
end

EDIT: idk if this is possible but maybe something like this..

--id is determined by function execution index
if await(60) then
 --done
end

for example..

await(60)--await id 0
await(60)--await id 1
await(60)--await id 2
--nextframe
await(60)--await id 0
await(60)--await id 1
await(60)--await id 2

storing a range of number in a table causes rounding issues

Fri, 21 Feb 2020 23:19:01 UTC

can someone tell me how to fix this bug?

function range(low,high,step)
    local t={}
    for i=low,high,step do
        add(t,flr(i/step)*step)--
    end
    return t
end

for example I am doing this for my menus..

function run_menu1()
    scene.upd = upd_menu1
    scene.drw = drw_menu1

    --options selectors
    optiony=1 --optiony
    options=
    {
                --optionx and options
        {1, {false , true       }}, --powerups
        {1, {"grow", "infinite" }}, --tail type
        {42,range(-4.0, 4.0, 0.1)}, --player speed
        {42,range(-4.0, 4.0, 0.1)}, --player accel on any deaths
        {1, range( 0.0,32.0, 1.0)}, --border size
        {42,range(-4.0, 4.0, 0.1)}, --border speed
        {42,range(-4.0, 4.0, 0.1)} -- border accel on any deaths
    }
end

implicit conversion between bools and numbers?

Sat, 15 Feb 2020 00:12:46 UTC

what do you guys think about a implicit conversion between bools a numbers being added?

it shouldn't hurt existing cartridges but would allow for something like this..

local axisy = btn(3)-btn(2)

normally you would need to write a num function that converts bools to numbers for something like this.

bounding box of drawn sprite?

Fri, 14 Feb 2020 23:05:10 UTC

can someone explain to me how to get a sprites bounding box?

I have this code which reads from the center of a sprite and keeps checking above it until the pixel is 0 or its at the top of the sprite.

function boxt(s,x,y,w,h)
    local sx1=flr(s%16)*(w*8)
    local sy1=flr(s/16)*(h*8)
    local sx2=sx1+(w*8)
    local sy2=sy1+(h*8)
    local cx =4
    local cy =4

        //find 0 pixel or top
    while sget(sx1+cx,sy1+cy) != 0 or sy1+cy > sy1 do
        cy-=1
    end

    sspr(sx1,sy1,sx2-sx1,sy2-sy1,x+cx,y+cy)

    return cy+y
end

however it doesn't seem to work

local s,x,y=22,63,63
function _draw()
    cls(1)
    if(boxt(s,x,y,1,1) > 0) then
        y-=1
    end
    //spr(s,x-4,y-4)
end

out of memory?

Tue, 16 Jul 2019 23:07:47 UTC

can someone tell me why I am running out of memory?

jajefutayu

by Shadowblitz16

[Click to Play]

@Catatafish I completely changed the question I realized i do not have an infinite loop. I just assumed since I was running out of memory.

this line seems to be doing it and idk why..

o:procx()

attempt to call global vec a table value?

Tue, 16 Jul 2019 05:14:10 UTC

can someone tell me why this throws the error "attempt to call global vec a table value"?
vec clearly has its metatable set with a call metaevent

vec=
{   
    x=0,
    y=0,
    mag=function(o) return sqrt (o.x^2+o.y^2) end,
 ang=function(o) return atan2(o.x,  o.y  ) end,
 nrm=function(o) return vec(o:ang()/360) end,  
}
vecmeta=
{
     __call=function(o,x,y)
      o  =o or {} 
            o.x=y and x or cos((x+90)/360)
            o.y=y and y or-sin((x+90)/360)  
            return setmetatable(o,vec)
        end,
        __eq=function(a,b)
            a=type(a) == "number" and vec(a,a) or a
            b=type(b) == "number" and vec(b,b) or b
            return (a.x==b.x and a.y==b.y)
        end,
        __add=function(a,b)
            a=type(a) == "number" and vec(a,a) or a
            b=type(b) == "number" and vec(b,b) or b
            return vec(a.x+b.x,a.y+b.y)
        end,
        __sub=function(a,b)
            a=type(a) == "number" and vec(a,a) or a
            b=type(b) == "number" and vec(b,b) or b
            return vec(a.x-b.x,a.y-b.y)
        end,
        __mul=function(a,b)
            a=type(a) == "number" and vec(a,a) or a
            b=type(b) == "number" and vec(b,b) or b
            return vec(a.x*b.x,a.y*b.y)
        end,
        __div=function(a,b)
    a=type(a) == "number" and vec(a,a) or a
            b=type(b) == "number" and vec(b,b) or b
            return vec(a.x/b.x,a.y/b.y)
        end,
}
setmetatable(vec, vecmeta)

local test =
{
    pos=vec(0,0),
    vel=vec(0,0),
}

table values are are nil

Sat, 13 Jul 2019 05:25:10 UTC

can someone tell me why I am getting nil when printing out the stars px and py values?

local stars={}
for i=0, 16 do add(stars,{x=rnd(128),y=rnd(128),px=x,py=y,c=7}) end --px and py are equal to x and y

drwmenu=function()
    if btn(2) then menuind-=1 end
    if btn(3) then menuind+=1 end
    menuind=mid(0,4)

    for v in all(stars) do
    print(v.px) --prints nil 
    print(v.py) --prints nil
        line(v.x,v.y,v.px,v.py,v.c)
        --line(v.x,v.y-128,v.px,v.py,v.c)
        --v.py=v.y

        --v.y+=8
        if v.y > 127 then v.y-=128 end
    end
    if (time()-last > 1) then
        rectfill(0,112,127,120,1)
        print("press start!",0,114,7)
        if (time()-last > 2) then last=time() end
    end
end

yield() outside of coroutines and inside functions?

Sat, 13 Jul 2019 03:08:39 UTC

does yield() work outside of coroutines and inside functions?

I feel coroutines are a pain to setup and update when it would just be easier to call yield inside a function
not to mention the tokens required to setup coroutines and call/update them

function wait(t)
  for x=1,t do yield() end
end

function test()
 wait(2)
 print("test")
 wait(2)
end

function _update()
 test()
end

90 degree rotation?

Wed, 10 Jul 2019 23:10:22 UTC

is there a build in function that rotates a drawn tile by 90 degrees for the 4 possible values of 0,1,2 and 3?

some functions I would like to see in pico8

Wed, 15 Aug 2018 22:36:21 UTC

EDITED 2/14/2020

I came up with several functions that I think would go good in pico8 and would reduce file size for larger games

--math

function ldx(d,l)  --stands for lengthdirx
    return cos(d)* l or 1
end

function ldy(d,l) --stands for lengthdiry 
    return sin(d)* l or 1
end

function ptl(x1,y1,x2,y2) --stands for point length
    return sqrt(((y2-y1)^2)+((x2-x1)^2))
end

function ptd(x1,y1,x2,y2) --stands for point direction
    return atan2(y2-y1,x2-x1)
end

function wrp(v,l,h) -- stands for wrap
    local o=v
    while(o < l) o += (h-l)
    while(o > h) o -= (h-l)
    return o
end

function rng(v, l1, h1, l2, h2) -- stands for range
    return l2 + (v - l1) * (h2 - l2) / (h1 - l1)
end

--vectors

function vec(vx,vy) --stands vector
    local m=
    {
        __eq =function(a,b)
            return (a.x==b.x and a.y==b.y)
        end,
        __add=function(a,b)
            return vec(a.x+b.x, a.y+b.y)
        end,
        __sub=function(a,b)
            return vec(a.x-b.x, a.y-b.y)
        end,
        __mul=function(a,b)
            return vec(a.x*b.x, a.y*b.y)
        end,
        __div=function(a,b)
            return vec(a.x/b.x, a.y/b.y)
        end
    }

    local v=
    {
        x=vx,
        y=vy,
    }

    return setmetatable(v,m)
end

--tables

function new(orig) --stands for new table
    local orig_type = type(orig)
    local copy
    if orig_type == 'table' then
        copy = {}
        for orig_key, orig_value in next, orig, nil do
            copy[deepcopy(orig_key)] = deepcopy(orig_value)
        end
        setmetatable(copy, deepcopy(getmetatable(orig)))
    else -- number, string, boolean, etc
        copy = orig
    end
    return copy
end

some notes..

while ldx, ldy, ptl and ptd wouldn't save alot of space they would be easier to understand and would definitly be used by newer programmers
the wrp function would wrap a number around a low and high value and would be useful besides just saving space.
for example if you wanted to make a spaceship game with wrapping borders
rng is another useful function that would take a value and 2 ranges of numbers and return a converted value between those ranges.
vec returns a 2d vector that allows operating on other vectors
new would just return a deep copy of the table u give it and would make oop easier and take less space up in the cart

online multiplayer based on synced inputs?

Sat, 11 Aug 2018 23:21:38 UTC

is there a plan to add built in pico8 multiplayer using synced inputs?

basically it would be handled in pico8 rather than the cart.

it would allow players to connect to each other via ip or game uid and official lexaloffle connecting servers through the pause menu.

this might be the easiest way to build a multiplayer game since there would be no packets being sent besides the hard coded inputs.

networked inputs would be accessible the same way normal inputs are with btn(btn, player).

this would also make multiplayer games have not just networked players but local ones as well.
players count would be limited to the number of inputs pico8 has.

simple function to rotate sprites around a point?

Fri, 10 Aug 2018 21:40:42 UTC

does anybody have a good rspr(n, x, y, w, h, r, ox, oy, flipx, flipy) function to draw rotated sprites?
I need this to make my 4 player spaceship battle game.

(solved)4 players for raspberry pi?

Sun, 04 Feb 2018 20:54:25 UTC

ok so I think I get how people like pico 8 for its limitations. but will pico 8 ever support 4 players simultaneously?

this would be good for things like raspberry pi where 4 players can sit on a couch and play small 4 player games together.
what do you guys think?
I know older hardware only supported up to 2 players but I think this would be a good idea for the compactness of pico8.

are limitations too strict?

Fri, 02 Feb 2018 20:59:37 UTC

I was just wondering everybody's opinion on the limitations of pico8?

right now there isn't really much we can do with it besides make very simple 1 level games.
pico8 could do much better if code limitations weren't so harsh.

also it seems people smash all there code together to preserve tokens which is not good
for example..
this takes up more space

local var = 0
      var = var + 1

then this

local var=0 var=var+1

which makes no sense

if code limitations were removed and cart loading time was reduced significantly
then pico8 could make much larger games while still saving to a small cart size.

what would even be better if pico 8 carts were separated into 2 parts

the compiled game
and the dev files

so what do you guys think?

keeping the games small maybe be fun but you can only do so much with it especially with the severe limitations of pico8.