freecell.lua

--[[
this is ~1400 characters and doesn't include auto-moving cards, sfx, proper card suits, etc.
(it's an earlier version of my pico1k jam entry)

It's not nearly as compressed as my <1024 character version (see https://pancelor.itch.io/free-cell-1k)
but it is similar enough that it might help you decipher the finished version.
Hopefully my comments help too.
]]

function rectwh(x,y,w,h,c) rect(x,y,x+w-1,y+h-1,c) end
function rectfillwh(x,y,w,h,c) rectfill(x,y,x+w-1,y+h-1,c) end

--t: number of frames since game start
--B: list of the cards that are flying in during the opening animation
--s: a list of "stacks". The game has 16 stacks:
--  0-7: the main play area
--  8-11: the free cells
--  12-15: the scoring area
t=-1A=24365w=13h=17s={}B={}C=fillp
p=poke
p(A,3)p(A-29,8,5,-5)p(A-20,1,-10,3) --enable mouse; edit palette
for i=0,51do
 s[i]={}
 a=i%13+1b=i\13+1
 add(B,{
  x0=58,y0=1,
  name="\f"..(i\26)..sub("a234567890jqk",a,a)..sub("♥◆♪⧗",b,b),
  id=i+i\13*3, --cards have ids 0-12, 16-28, 32-44, and 48-60. Useful for bitwise logic-checking later
 },rnd(i+1)\1+1)
end

function set_home(cr,i)
 --moves card cr to stack i
 assert(i<16,i)
 del(s[cr.home],add(s[i],cr))
 cr.home=i
 cr.x1,cr.y1,z=stack_base(i)
 cr.y1+=z
end

function stack_base(i)
 --returns the coordinates of the next place a card should go in stack i
 -- (returns x,y,z, where x,y is the base of the stack and x,y+x is the top of the stack)
 a=i\8return i*(15-a)+a*(i\12*14-114)+4,23-a*22,(1-a)*max(#s[i]*6-6)
end

function draw_card(cr)
 --bitplane shadows! search for "0x5f5e" in https://pico-8.fandom.com/wiki/Memory
 -- basically, this adds 8 to every color the rectwh draws over (instead of actually drawing over it)
 p(A+49,248)rectwh(cr.x0-1,cr.y0-1,14,h,8)p(A+49,-1)

 rectfillwh(cr.x0,cr.y0,w,h,7)
 print(cr.name,cr.x0+1,cr.y0+1)
end

::_:: --setup is done; time to define the main game loop
t+=1ml=mb mb=btn(5)mx=stat(32)my=stat(33)
if #B>0then --continue starting animation
 set_home(deli(B),t%8)
end

for i=0,15do
 st=s[i]
 x,y,z=stack_base(i)
 C(▒)rectwh(x,y,w,h,2)C() --draw base pad
 for cr in all(st)do
  --move each card from its current pos (x0,y0) towards its target pos (x1,y1)
  dx,dy=cr.x1-cr.x0,cr.y1-cr.y0
  div=dx^2+dy^2<1 and 1 or 2
  cr.x0+=dx/div
  cr.y0+=dy/div
  if(cr~=crh)draw_card(cr)
 end

 top=st[#st]
 if(i<8)y+=z

 -- crh is the card we're holding
 -- top is the top card of the stack we're hovering the mouse over
 -- crh.id (and top.id) are integer ids for the cards; the cards altogether have ids 0-12, 16-28, 32-44, and 48-60
 if x<=mx and mx<x+w and y<=my and my<y+h then --if mouse is colliding,
  if crh and not mb and (   --if we're holding a card and just released the mouse button,
    i<12 and not top        --(you can place any card in a bottom or top left stack if the stack is empty)
    or i<8 and 1+crh.id^^32|16==top.id|16                    --(bottom cards stack descending w/ alternating colors)
    or i>11 and (top and crh.id==top.id+1 or crh.id&15<1)    --(scoring cards stack ascending w/ same suit)
  ) then
   set_home(crh,i)
  end
  if(mb and not ml and i<12)crh=top --pick up the card
 end
end
if crh then
 -- move and draw the held card
 crh.x0=mx-6
 crh.y0=my-8
 draw_card(crh)
 if(not mb)crh=nil
end
?"●\^1\^c3",mx-4,my-1,9 --draw the mouse; flip(); cls()
goto _