Issues when Sorting table [Solved]

[NoreoAlles]

Hello,
i want to sort a table containing triangles, which all contains 3 3d-vectors each, by the average of all z coponents of the vectors in the triangle.
(Which ever triangle has the lower z gets drawn earlier). I have my attempt here line 133 (and the source):

Code: Select all

function Sort_Triangles(list)
    local i = 1
    table.sort(list,function (a, b)
        i = i+1
        if i+1 > #list then i = 1 end
        print(i)
        return (list[i].vectors[1].z + list[i].vectors[2].z + list[i].vectors[3].z)/3 > (list[i+1].vectors[1].z + list[i+1].vectors[2].z + list[i+1].vectors[3].z)/3 end)
    for i=1, #list do 
       love.graphics.polygon("fill", 
       list[i].vectors[1].x, list[i].vectors.vectors[1].y,
       list[i].vectors.vectors[2].x, list[i].vectors.vectors[2].y, 
       list[i].vectors[3].x,list[i].vectors.vectors[3].y)
        love.graphics.setColor( 0, 0,  0)
    end
end

I really cant understand the table.sort function and i would appriciate any help with writing my algorythm and explanetions of table.sort

[MrFariator]

table.sort optionally takes a function as its second argument, which it will use to determine if element 'a' should be sorted before element 'b'. If the function returns true, then element 'a' is determined to be in the table before 'b', and vice versa for false. In your code, you're trying to traverse the table inside your custom sorter, and effectively entirely ignoring the 'a' and 'b' elements the function is receiving, which probably causes very incorrect results.

So, you'd need to modify your function to be like this:

Code: Select all

local customSorter = function ( a, b )
  return (a.vectors[1].z + a.vectors[2].z + a.vectors[3].z)/3 > (b.vectors[1].z + b.vectors[2].z + b.vectors[3].z)/3
end

-- usage:
table.sort (list, customSorter)

If you're constantly using this custom sort function, it's better to declare in a way that you can continuously reuse it, like as a local.

In order to flip the sorter to sort lowest triangles first, you'd likely need to flip the ">" to "<", however.

[NoreoAlles]

table.sort optionally takes a function as its second argument, which it will use to determine if element 'a' should be sorted before element 'b'. If the function returns true, then element 'a' is determined to be in the table before 'b', and vice versa for false. In your code, you're trying to traverse the table inside your custom sorter, and effectively entirely ignoring the 'a' and 'b' elements the function is receiving, which probably causes very incorrect results.

So, you'd need to modify your function to be like this:

Code: Select all

local customSorter = function ( a, b )
  return (a.vectors[1].z + a.vectors[2].z + a.vectors[3].z)/3 > (b.vectors[1].z + b.vectors[2].z + b.vectors[3].z)/3
end

-- usage:
table.sort (list, customSorter)

If you're constantly using this custom sort function, it's better to declare in a way that you can continuously reuse it, like as a local.

In order to flip the sorter to sort lowest triangles first, you'd likely need to flip the ">" to "<", however.

First: Thank you, that worked .
Secondly: I thought i had to make my own iterator, but thats whats been giving me errors hahhaha
Its working now, heres a beautifully 3d rendered screenshot: