Add display_format_alpha

diff --git a/lib/SDL/Surface.pm b/lib/SDL/Surface.pm
index 897234c..4485824 100644 (file)
--- a/lib/SDL/Surface.pm
+++ b/lib/SDL/Surface.pm
@@ -239,6 +239,14 @@ sub display_format {
        $self;
 }
 
+sub display_format_alpha {
+       my $self = shift;
+       my $tmp = SDL::DisplayFormatAlpha($$self);
+       SDL::FreeSurface ($$self);
+       $$self = $tmp;
+       $self;
+}
+
 sub rgb {
        my $self = shift;
        my $tmp = SDL::ConvertRGB($$self);
@@ -525,6 +533,11 @@ C<alpha> takes a value from 0x00 to 0xff.
 C<SDL::Surface::display_format> converts the surface to the same format as the
 current screen.
 
+=head2 display_format_alpha ()
+
+C<SDL::Surface::display_format_alpha> converts the surface to the same format as the
+current screen, plus an alpha channel.
+
 =head2 rgb ()
 
 C<SDL::Surface::rgb> converts the surface to a 24 bit rgb format regardless of the initial format.