added grid aligned role

eg/06-sprite.pl

@@ -29,7 +29,7 @@ sub on_mouse_button_up {
     my $self = shift;
     push @{$self->children}, Games::CamelDefense::eg_StickySprite->new(
         rect     => $self->rect,
-        image    => 'arrow',
+        image    => $self->image,
         layer    => 'middle',
         centered => 1,
     );

eg/08-grid-aligned-sprite.pl

@@ -0,0 +1,49 @@
+#!/usr/bin/perl
+
+package Games::CamelDefense::eg_GridAlignedSprite;
+use Games::CamelDefense::Demo qw(Grid::Markers);
+
+consume qw(Render::Sprite Grid::Aligned);
+
+# ------------------------------------------------------------------------------
+
+package Games::CamelDefense::eg_GridAlignedSprite_Cursor;
+use Games::CamelDefense::Demo;
+
+has children => (is => 'ro', required => 1, default => sub { [] });
+has markers  => (is => 'ro', required => 1, handles => [qw(cell_center_xy)]);
+
+consume qw(Behavior::Cursor Render::Sprite);
+
+sub on_mouse_button_up {
+    my $self = shift;
+    push @{$self->children}, Games::CamelDefense::eg_GridAlignedSprite->new(
+        rect    => $self->rect,
+        image   => $self->image,
+        markers => $self->markers,
+        layer   => 'middle',
+    );
+}
+
+# ------------------------------------------------------------------------------
+
+package main;
+use Games::CamelDefense::Demo qw(Grid::Markers);
+use Games::CamelDefense::App title       => 'Grid Aligned Sprite',
+                             size        => [640, 480],
+                             layers      => [qw(middle top)],
+                             hide_cursor => 1;
+
+my $markers = Markers->new
+    (size => App->size, xy => [0, 0], spacing => 32);
+
+my $cursor = Games::CamelDefense::eg_GridAlignedSprite_Cursor->new(
+    rect     => [100, 100, 22, 26],
+    image    => 'arrow',
+    layer    => 'top',
+    markers  => $markers,
+);
+
+App->run;
+
+

lib/Games/CamelDefense/Behavior/Cursor.pm

@@ -0,0 +1,34 @@
+package Games::CamelDefense::Behavior::Cursor;
+
+use Games::CamelDefense::Role;
+
+consume qw(
+    Geometry::Positionable
+    Event::Handler::SDL
+);
+
+sub on_mouse_motion { shift->xy([@_]) }
+
+sub on_app_mouse_focus { shift->is_visible(pop) }
+
+1;
+
+
+=head1 NAME
+
+Games::CamelDefense::Behvaior::Cursor - position follows mouse
+
+
+=head1 DESCRIPTION
+
+A positionable that sets its position on mouse motion, and hides when app loses
+focus.
+
+
+=head1 DOES
+
+L<Games::CamelDefense::Geometry::Positionable>, L<Games::CamelDefense::Event::Handler::SDL>
+
+=cut
+
+

lib/Games/CamelDefense/Grid/Aligned.pm

@@ -0,0 +1,58 @@
+package Games::CamelDefense::Grid::Aligned;
+
+use Games::CamelDefense::Role qw(Grid::Markers);
+
+consume 'Geometry::Rectangular';
+
+has markers => (
+    is       => 'ro',
+    required => 1,
+    isa      => Markers,
+    handles  => [qw(cell_center_xy)],
+);
+
+around BUILDARGS => sub {
+    my ($orig, $class, %args) = @_;
+    $args{centered} = 1;
+    return $class->$orig(%args);
+};
+
+after BUILD => sub {
+    my $self = shift;
+    $self->align_to_cell_center($self->xy);
+};
+
+sub align_to_cell_center {
+    my ($self, $xy) = @_;
+    $self->xy( $self->cell_center_xy($xy) );
+}
+
+1;
+
+
+=head1 NAME
+
+Games::CamelDefense::Grid::Aligned - a positionable centered on cell center
+
+
+=head1 DESCRIPTION
+
+Treat as a normal positionable, but provide with grid markers in constructor.
+You can set xy using C<align_to_cell_center($xy)>, where C<$xy> is a 2D 
+array ref. The positionable will always be centered on the cell center of
+the cell that includes the C<$xy> position.
+
+
+=head1 REQUIRES
+
+L<Games::CamelDefense::Grid::Markers> in C<markers> key of constructor
+
+
+=head1 DOES
+
+L<Games::CamelDefense::Geometry::Rectangular>
+
+
+=cut
+
+

lib/Games/CamelDefense/Grid/Markers.pm

@@ -55,7 +55,7 @@ sub cell_center_xy {
     my ($self, $xy) = @_;
     my $pos    = V( @{ $self->compute_cell_pos($xy) } );
     my $s      = $self->spacing;
-    my $offset = $self->xy_vec;
+    my $offset = $self->xy;
     return [@{ $offset + $pos * $s + V($s/2, $s/2) }];
 }
 

lib/Games/CamelDefense/Render/Paintable.pm

@@ -38,7 +38,7 @@ sub sdl_paint {
 
 # permonks stvn trick to get BUILD time action from roles
 sub BUILD {}
-before 'BUILD' => sub {
+before BUILD => sub {
     my $self = shift;
     $Layer_Manager->add_paintable_to_layer($self->layer, $self)
         if $self->auto_paint;