Path fails to return when starting from an unwalkable location

[vitalitymobile]

Hi Yonaba, I am using Jumper in my project and setup the map like bellow. But when i try to move gem from 5,3 to 4,3 (that i think it nearby and possible to move) it show can not move. Can you check it?

Thanks!

local Jumper = require 'Jumper.init'
local map = {
    {0,1,1,1,0,1,1},
    {1,1,1,1,1,1,1},
    {0,0,1,0,1,1,1},
    {1,1,1,1,1,1,1},
}

local walkable = 0
local postProcess = false
local pather = Jumper(map,walkable,postProcess)
local sx,sy = 5,3
local ex,ey = 4,3
print('Hello Jumper! from Gideros')
local path = pather:getPath(sx,sy,ex,ey)
if path then
  print(('Path from [%d,%d] to [%d,%d] was : found!'):format(sx,sy,ex,ey))
  for i,node in ipairs(path) do
    print(('Step %d. Node [%d,%d]'):format(i,node.x,node.y))
  end
else
    print(('Path from [%d,%d] to [%d,%d] was : not found!'):format(sx,sy,ex,ey))
end  

[Yonaba]

Hi @vitalitymobile, Well, that's a little issue I planned to fix, since it occurs on very specific cases (more precisely when the first step goes from an unwalkable node) but for some reasons I lost track of it on my to-do list. Thanks poiting it out, though. I'll push a commit as soon as I reach my workstation.

PS: Looking at the example you provided, it seems you're using an outdated version of Jumper. I strongly recommend to move to the latest stable (1.8.0). They have been a few changes. You can take a look at the Readme for usage examples and verbose explanations.

Thanks for your feedback.

[vitalitymobile]

Thanks for your quick reply. Another question, In each move step, do I have to call an init Jumper like this:

self.pather = Jumper(map,self.walkable,self.postProcess) local path = self.pather:getPath(sx,sy,ex,ey);

Or is there any way to simple call getPath when need ( ofcourse the map logic change before call)

[Yonaba]

Unless I totally missed what you meant saying map logic change before call, I'd rather say no, you don't need this at all. You might want to explain the idea a little more, though. Thanks.

[vitalitymobile]

Yes, sorry for my bad of English In my game, after user make a correct move, i update map table, and when user going to another move, i must check for path, so my question is in this case, do i have to call self.pather = Jumper(map,self.walkable,self.postProcess) again

or just call local path = self.pather:getPath(sx,sy,ex,ey);

Thanks!

[Yonaba]

Updating the map won't require to init again a new pathFinder instance, as in the code, while processing a path computation, the pathFinder will always check for each node being expanded if it is walkable or not. On the fly. That's a feature added as of v1.6.3. So, well, you won't need to init anything again if you're using this version, or more recent. Just keep calling getPath.

[srdjan-m]

I would like to add that Jumper works deadly fast! I the game that I am currently working on I am calling getPath three times per second and there is no visible slowdown at all. Great work!

[vitalitymobile]

Thanks Yonaba, now I understand it! Please fix the bug soon so I can use it in my next game! Can I quick fix this by set the starting node to walkable?

[Yonaba]

Yes, making the first node walkable would work. But that might not be necessary. Try the latest v1.8.1 Well, you might want to take a look at the Readme, since it seems you're using an outdated version, newer updates might break your code. Let me know if there is any problem.

[vitalitymobile]

It works like a charm now! Thanks you so much Yonaba!