Discipulus has asked for the wisdom of the Perl Monks concerning the following question:

Hello monks,

I have an array of arrays full of o and, given the coordinates of one element and a radius I want to change all elements around the center into x

My AoA can be eventually big so I do not want to process every element of the AoA.

The sub ( illuminate in the example below ) must not complain if a point is outside of the AoA (for example giving a corner as vertex).

A pure perl solution will be the best, but also using modules will be ok.

Sorry if I only have the below sketch but I'm very scarce in trig and until now I can only figure to hardcode series of coordinates relative to the vertex (that is silly..)

use strict; use warnings; my $max = 19; my @aoa = map { [ ( 'o' ) x ($max + 1) ] } 0..$max ; display( @aoa ); # @to_change will contain [row1,col1],[row2,col2]... my @to_change = illuminate( 5, 4, 6 ); sub illuminate{ my $center_row = shift; my $center_col = shift; my $radius = shift; ... } sub display{ foreach my $row ( @_ ){ foreach my $col ( @$row ){ print $col; } print "\n" } }



PS the above code displays the AoA before the change: I want to be able to select into @to_change the serie of elements falling inside the circle.

minor changes to explain better

UPDATE June 24 2019 see also 2d field of view, vision algorithm in grid (ray casting)

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