How does this bresenham code even work?

[prixt]

https://github.com/kikito/bresenham.lua ... senham.lua

I understand what the bresenham algorithm is and how it works, but I just cannot wrap my head around why this code actually works.

[marco.lizza]

This is, quite frankly, the Lua statement-to-statement adaptation of a standard implementation of the (integer based) Bresenham line algorithm.

The only difference from the line-plotting case is that you are calling a callback function to check for visibility occlusion and test whether the line from point (x0,y0) to point (x1,y1) do not cross any "wall".

By the way, I implemented a LOS algorithm in a very similar way.

What puzzles you the most?