Re: Path algorithm

[Matthew Aylward]

Steve,
i have a few image processing algorithms that i have modified to work on
discrete2ds and grid2ds. The standard "flood fill" would achieve this,
what it does is recursively search adjoining cells for a particular
criteria. All that is needed to modify it is to add your
own "check_cell" function pointer similar to a quick sort "compare"
function. If the flood fill reaches the cell you want to check then there 
is an unbrocken path to it along which the criteria is met. You could set
it to break out of the search when the particular cell is reached.
you also need to decide between an 8-cell search neighbourhood which
considers diagonals to be a connection, or a 4-cell which only counts
horizontal or vertical connections.
If this sounds like it could be any use let me know and I will send you
the code. (It is at work and I'm writing this at home.)
Cheers,
Matt 

On Thu, 1 Mar 2001, M Lang / S Railsback wrote:

> I need an algorithm to see if you can get from one place in a Grid2D to
> another region of the grid.
> 
> Say there are a patch of connected grid cells that are "safe" for my
> fish. The other cells are either wet or dry, and the fish can only move
> through wet cells. I need to determine for each wet cell whether or not
> there is a connection through the other wet cells to the "safe" patch.
> 
> Does anyone have an efficient algorithm for this? 
> 
> Thanks
> 
> Steve
> -- 
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