#!/usr/bin/perl -w

use strict;
use warnings;

use Tk;
use Tk::Canvas;

my $mw = MainWindow->new();
$mw->state('zoomed');

my $canvas =
	$mw->Canvas()->pack(-expand => 1, -fill => 'both');
	
my %coord_1 = (
	'a' => [100,100,'b'],
	'b' => [200,100,'c'],
	'c' => [200,200,'d'],
	'd' => [150,250,'e'],
	'e' => [100,200,'a'],
);

my %coord_2 = (
	'f' => [250,250,'g'],
	'g' => [300,200,'h'],
	'h' => [300,300,'i'],
	'i' => [250,350,'j'],
	'j' => [200,300,'f'],
);

drawPolygon($canvas, \%coord_1, 'yellow');
my $moving_pol =  drawPolygon($canvas, \%coord_2, 'lightblue');

$mw->bind('<Up>', sub{movePolygon($canvas,$moving_pol,0,-5);});
$mw->bind('<Down>', sub{movePolygon($canvas,$moving_pol,0,5);});
$mw->bind('<Left>', sub{movePolygon($canvas,$moving_pol,-5,0);});
$mw->bind('<Right>', sub{movePolygon($canvas,$moving_pol,5,0);});

Tk::MainLoop;

sub drawPolygon{
	my $widget	= shift;
	my $coord	= shift;
	my $color	= shift;
	
	my @coords;
	foreach my $point (sort keys %{$coord}){
		push(@coords, $coord->{$point}->[0], $coord->{$point}->[1]);
	}

	return  $widget->createPolygon(
		@coords,
		-fill => $color,
		-outline => 'black',
	);
}

sub movePolygon{
	my $widget	= shift;
	my $polygon = shift;
	my $x_move = shift;
	my $y_move = shift;
	
	foreach my $point (sort keys %coord_2){
		$coord_2{$point}->[0] += $x_move;
		$coord_2{$point}->[1] += $y_move;
	}

	$widget->move($polygon, $x_move, $y_move);
	
	if (PolygonsOverlap(\%coord_1,\%coord_2)){
		$widget->itemconfigure(
			$polygon, 
			-outline	=> 'red',
			-fill => 'lightgreen',
		);
	}else{
		$widget->itemconfigure(
			$polygon, 
			-outline	=> 'black',
			-fill => 'lightblue',
		);
	}
}

sub PolygonsOverlap{
	my %coord_1 = %{shift()};
	my %coord_2 = %{shift()};
	
	#################################
	# algorithmus zum testen, ob sich
	# die polygone überschneiden.
	#################################
}