use strict;
use warnings;
use SDL;
use SDLx::App;
use SDLx::Rect;
use SDL::Events;
use SDL::Event;


my $app=SDLx::App->new(w=>800,h=>600,title=>"Movement!",d=>32,exit_on_quit=>1);

#The rectangle that we'll be moving around.
my $rect=SDLx::Rect->new(200,200,40,40);

#x and y velocities.
#For simplicity's sake, we'll have zero acceleration.
my $v_x=0;
my $v_y=0;

#Basic rendering handler.
$app->add_show_handler(sub{
	$app->draw_rect([0,0,$app->width,$app->height],[0,0,0,255]);
	$app->draw_rect($rect,[0,0,255,255]);
	$app->update;
	}
);	


$app->add_event_handler(sub{
	my ($event,$app)=@_;

	#Set velocity equal to plus or minus 2 depending on ASWD direction.
	if($event->type == SDL_KEYDOWN)
	{
		my $key= lc(SDL::Events::get_key_name($event->key_sym));

		if($key eq 'a')
		{
			$v_x=-2;
		}
		elsif($key eq 'd')
		{
			$v_x=2;
		}
		elsif($key eq 'w')
		{
			$v_y=2;
		}
		elsif($key eq 's')
		{
			$v_y=-2;
		}
	}
	elsif($event->type == SDL_KEYUP) #Reset velocity if key is released.
	{
		my $key= lc(SDL::Events::get_key_name($event->key_sym));	
		if($key eq 'a' or $key eq 'd')
		{
			$v_x=0;
		}
		elsif($key eq 'w' or $key eq 's')
		{
			$v_y=0;
		}
	}	
});

#Quit when "q" is pressed.
$app->add_event_handler(sub{
	my $event=shift;
	if($event->type == SDL_KEYDOWN)
	{
		if(lc(SDL::Events::get_key_name($event->key_sym)) eq 'q')
		{
			$app->stop;
		}
	}
});	


$app->add_move_handler(\&move);

sub move
{
	my ($step,$app,$t)=@_;
	return unless $step;

	#Gather x and y coordinates of rectangle.
	my $x=$rect->x;
	my $y=$rect->y;

	#Adjust positions accordingly.
	$x+=$v_x * $step;
	$y-=$v_y * $step;

	#Set new coordinates.
	$rect->x($x);
	$rect->y($y);
	
	#Debugging, to figure out WTF is going on.
	#print "$v_x,$v_y,$t\n";
}	

$app->run();