#!/usr/bin/perl -w

use strict;
use SDL::App;
use SDL::Surface;
use SDL::Event;

$| = 1;
my (@update_rects, @fire_items, %images, $app, $event, $background);

sub init_sdl {
	my $sdlflags = SDL_ANYFORMAT | SDL_HWSURFACE | SDL_DOUBLEBUF | SDL_HWACCEL | SDL_ASYNCBLIT;
	$app = new SDL::App ( -flags => $sdlflags,-title => 'Space',-width => '800',-height => '600');
	$event = new SDL::Event;
	$event->set(SDL_SYSWMEVENT,SDL_IGNORE);
	$background = new SDL::Surface(-width => $app->width, -height => $app->height, -depth => 32, -Amask => '0 but true');


	#load images
	foreach ('ship', 'beam1') {
	$images{$_} = new SDL::Surface(-name => "/home/mirage/perl/space/images/$_.png");
	$images{$_}->{-surface} or die "FATAL: Couldn't load image file $_.\n";
	}
	
}

sub put_image($$$) {
    my ($image, $x, $y) = @_;
    my $rect = new SDL::Rect(-width => $image->width, -height => $image->height);
    my $drect = new SDL::Rect(-width => $image->width, -height => $image->height, -x => $x, -y => $y);
    $image->blit($rect, $app, $drect);
    push @update_rects, $drect;
}

#sub fillrect {
#	my ($width, $height, $x, $y) = @_;
#	my $rect = new SDL::Rect(-width => $width, -height => $height, -x => $x, -y => $y);
#	$app->fill($rect,0x000000);
#}

sub erase_image_from($$$$$) {
    my ($width, $height, $x, $y, $img) = @_;
    my $drect = new SDL::Rect(-width => $width, -height => $height, -x => $x, '-y' => $y);
    $img->blit($drect, $app, $drect);
    push @update_rects, $drect;
}

sub erase_image($$$$) {
    my ($width, $height, $x, $y) = @_;
    erase_image_from($width, $height, $x, $y, $background);
}

sub handle_fire {
	my ($new, $x, $y) = @_;
	my $skip = 0;
	if($new){ push(@fire_items, $x.' '.$y); }
	my $i = 0;
	while($i < @fire_items) {
		my ($xc, $yc) = split(' ',$fire_items[$i]);
		splice(@fire_items,$i,1) and $skip = 1 unless $xc < $app->width + $images{'beam1'}->width;
		if($skip){ $skip = 0; next; }
		&erase_image($images{'beam1'}->width, $images{'beam1'}->height,$xc-10,$yc);
		&put_image($images{'beam1'}, $xc, $yc);
		$fire_items[$i]=join(' ',$xc + 10, $yc);
		$i++;	
	}
}

&init_sdl;

my $x = 50;
my $y = ($app->height / 2) - $images{'ship'}->height;
my ($xplus, $yplus, $xminus, $yminus, $fire) = 0;

while(1) {
$event->pump();
if ($event->poll != 0) {
	if ($event->type == SDL_KEYDOWN) {
		my $key = $event->key_sym();
		
		$xplus = 1 if $key eq SDLK_RIGHT;
		$xminus = 1 if $key eq SDLK_LEFT;
		$yminus = 1 if $key eq SDLK_UP;
		$yplus = 1 if $key eq SDLK_DOWN;
		$fire = 1 if $key eq SDLK_SPACE;

		exit if $key eq SDLK_ESCAPE;
	}

	if ($event->type == SDL_KEYUP) {
		my $key = $event->key_sym();
		
		$xplus = 0 if $key eq SDLK_RIGHT;
		$xminus = 0 if $key eq SDLK_LEFT;
		$yminus = 0 if $key eq SDLK_UP;
		$yplus = 0 if $key eq SDLK_DOWN;
		$fire = 0 if $key eq SDLK_SPACE;
	}	
}


#delete if movement
if($xplus or $xminus or $yplus or $yminus) {
&erase_image($images{'ship'}->width, $images{'ship'}->height,$x,$y);
}

#change values if key is pressed
my $step = 10;
$x+=$step if $xplus and $x < ($app->width - $images{'ship'}->width);
$x-=$step if $xminus and $x >= $step;
$y+=$step if $yplus and $y < ($app->height - $images{'ship'}->height);
$y-=$step if $yminus and $y >= $step ;

#draw gunshots, possibly add new one
&handle_fire($fire, $x, $y);

#draw ship
&put_image($images{'ship'},$x,$y);
$app->update(@update_rects);
@update_rects=();
&SDL::DisplayFormat($images{'ship'}->{-surface});
&SDL::Delay(20);
}

__END__