My pathfinding code doesn't work!

[GoldenTCat]

I'm trying to create a pathfinding algorithm by myself, but every time I run the program and press space to create a 'path' the TIC-80 itself crashes and I have to open it again and I don't know what's wrong.

Here is the code:

t=0
ti, tr = table.insert, table.remove
pl={x=16, y=64}

path={}
--create path
function path:new(x, y, parent)
ti(self, {
x = x, y = y,
t = 30,
id = #path+1,
spread = true,
parent = parent
})
end
function path:updt()
for i, p in ipairs(self)do
if p.t>0 then p.t=p.t-1 end
if p.spread and keyp(48) then --aaaaaaaaaaaaaaaaaaaa

for k, pa in ipairs(path)do

  if p.t<=0 then
   trace("create")
   path:new(pl.x, pl.y, i)
  end
--ignore this
--[[for dx=-8, 8, 8 do
 for dy=-8, 8, 8 do
  
  if (p.x+dx)//8 ~= pa.x//8 and p.t <= 0
  and (p.y+dy)//8 ~= pa.y//8 
  and p.x+dx > 0 and p.x+dx < 240 
  and p.y+dy > 0 and p.y+dy < 136 then
   trace("create")
   path:new(p.x+dx, p.y+dy, i)
  end
 end
end]]

end
p.spread = false
end
end
end
function path:draw()
for i, p in ipairs(self)do
if i>1 then line(p.x+4, p.y+4,
path[p.parent].x+4, path[p.parent].y+4, 15) end
rectb(p.x, p.y, 7, 7, 15)
print(p.parent, p.x+2, p.y+1, 14, false, 1, true)
end
end

path:new(pl.x//88, pl.y//88, 0)

function TIC()
t=t+1
cls(0)
map()

--player control
if btn(0) then pl.y = pl.y - 1 end
if btn(1) then pl.y = pl.y + 1 end
if btn(2) then pl.x = pl.x - 1 end
if btn(3) then pl.x = pl.x + 1 end

--path functions
path:updt()
path:draw()

--player img
spr(16, pl.x, pl.y, 0)
end

[end of the code]

Please someone who can solve this help me

[soxfox42]

First of all, could you please post your code inside a code block? Pasting it directly into the comment breaks, the formatting, especially in the line path:new(pl.x//88, pl.y//88, 0), which I'm assuming started out as path:new(pl.x//8*8, pl.y//8*8, 0)

I'm not sure entirely what you're going for with this code, so I won't try to completely fix it, but I can at least point out why it crashes/freezes. In path:updt, you're looping over every point in the path, and adding a new point if space is pressed. Because there is now another point in path, the loop continues, and tries to spread from that new point, getting stuck forever. You probably want to keep track of new points somewhere separate, so that you don't loop forever over new points.

I also don't think the nested loop has the behaviour you want. In the current version, when a point is spread, the inner loop adds a new point for every other point that already exists. That means if you have 5 points currently in the path table, 25 new points are added - 5 for the first, 5 for the second, and so on.

The commented version of the loop is also wrong. I'm guessing you're trying to only add a point if it's not already in the path table, but instead I think this adds one copy of each point for every other point, except the ones that are already at that location. You'll need to check whether the point is in the table at all, and then use that to add only one copy of the new point.

[eliaswolfy]

I think you can get better help on the official Tic-80 discord