-Hello Mouse? An Example of the New Event Code +SDL RC 2.5 decides to play with PDL
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-You need the new code from the redesign branch to use this .
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Any code that is not marketed is dead code
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---mst
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-You need the new code from the redesign branch to use this .
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-
#!/usr/bin/env perl
-
-use SDL;
-use SDL::Events;
-use SDL::Event;
-use SDL::Video;
-
-SDL::init(SDL_INIT_VIDEO);
-
-my $display = SDL::Video::set_video_mode(640,480,32, SDL_SWSURFACE );
-my $event = SDL::Event->new();
-
-while(1)
-{
- SDL::Events::pump_events();
-
- if(SDL::Events::poll_event($event) && $event->type == SDL_ACTIVEEVENT)
- {
- print "Hello Mouse!!!\n" if ($event->active_gain && ($event->active_state == SDL_APPMOUSEFOCUS) );
- print "Bye Mouse!!!\n" if (!$event->active_gain && ($event->active_state == SDL_APPMOUSEFOCUS) );
- }
+PDL provides great number crunching capabilities to Perl and SDL provides game-developer quality real-time bitmapping and sound.
+You can use PDL and SDL together to create real-time,
+responsive animations and simulations.
+In this section we will go through the pleasures and pitfalls of working with both powerhouse libraries. -- David Mertnes
+
+
+Creating a SDL Surface piddle
+PDL's core type is a piddle.
+Once a piddle is provided to PDL it can go do a numerous amounts of things.
+Please see the example in 'examples/cookbook/pdl.pl' in github.
+
+Creating a simple piddle
+First lets get the right modules.
+
+ use PDL;
+ use SDL::Rect;
+ use SDL::Video;
+ use SDL::Surface;
+ use SDL::PixelFormat;
+
+Suppose you want a surface of size (200,400) and 32 bit (RGBA).
+
+my ( $bytes_per_pixel, $width, $height ) = ( 4, 200, 400 );
+
+Define the $width, $height and $bytes_per_pixel. Your $bytes_per_pixel is the number of bits (in this case 32) divided by 8 bits per byte. Therefore for our 32 bpp we have 4 Bpp;
+
+my $piddle = zeros( byte, $bytes_per_pixel, $width, $height );
+
+Create a normal $piddle with zeros, byte format and the Bpp x width x height dimensions.
+
+my $pointer = $piddle->get_dataref();
+
+Here is where we get the acutal data the piddle is pointing to. We will have SDL create a new surface from this function.
+
+my $surface = SDL::Surface->new_from( $pointer, $width, $height, 32,
+ $width * $bytes_per_pixel );
+
+Using the same dimensions we create the surface using SDL::Surface->new_form(). The $width * $Bpp is the scanline (pitch) of the surface in bytes.
+
+warn "Made surface of $width, $height and ". $surface->format->BytesPerPixel;
+ return ( $piddle, $surface );
+
+Finally make sure that the surface acutally has the correct dimensions we gave.
+
+NOTE: $surface->format->BytesPerPixel must return 1,2,3,4. !!
+
+Now you can blit and use the surface as needed; and do PDL operations as required.
+
+Operating on the Surface safely
+To make sure SDL is in sync with the data. You must call SDL::Video::lock before doing PDL operations on the piddle.
+
+SDL::Video::lock_surface($surface);
+
+ $piddle ( :, 0 : rand(400), 0 : rand(200) ) .= pdl( rand(225), rand(225), rand(255), 255 );
+
+After that you can unlock the surface to blit.
+
+SDL::Video::unlock_surface($surface);
+
+Errors due to BPP at blitting
+When blitting the new surface check for the return value to see if there has been a problem.
+
+my $b = SDL::Video::blit_surface(
+ $surface, SDL::Rect->new( 0, 0, $surface->w, $surface->h ),
+ $app, SDL::Rect->new( ( $app->w - $surface->w ) / 2, ( $app->h - $surface->h ) / 2, $app->w, $app->h )
+ );
- exit if($event->type == SDL_QUIT);
-}
-
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