X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=sdlgit%2FSDL-Site.git;a=blobdiff_plain;f=pages%2Fblog-0012.html-inc;h=b1abc1d15ace99fb968ddcc0866bb1101ddb8cbf;hp=706ea537074945bb91e1162b2494c72640b80ed3;hb=e785862422f3e827a242fc244bd57b23443887ce;hpb=879fff64432f43c80083c7b45da72611be9dca4b diff --git a/pages/blog-0012.html-inc b/pages/blog-0012.html-inc index 706ea53..b1abc1d 100644 --- a/pages/blog-0012.html-inc +++ b/pages/blog-0012.html-inc @@ -1,77 +1,23 @@

-SDL RC 2.5 decides to play with PDL +Huge World Maps in less then 100 lines

-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
+

+Hello folks,

+Recently we have been working on making the Perl syntax sugar for SDL in the form of SDLx. So far we have got the SDLx::Surface and SDLx::Sprite (garu++) done. So the first thing we did was throw together a quick Zelda map walker. As you can see above.  The code is at http://gist.github.com/478440. The SDL code that this depends on will be SDL 2.503 soonish . We are in the process of cleaning up some more SDLx and Alien::SDL bugs. After that SDLx::App will be overhauled to make this sort of thing even easier. Finally living up to our goal of  'Simple Games Easy. Complex Games Possible.' 

-

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.
+UPDATE: with some help, and newcomer jtpalmer's help we have added Link
+ 

-
  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 )
-       );
- 
-    die "Could not blit: " . SDL::get_error() if ( $b == -1 );
-

-If the error message is 'Blit combination not supported' that means that the BPP is incorrect or incosistent with the dimensions. After that a simple update_rect will so your new surface on the screen. -


-

\ No newline at end of file +--caio yapgh
+


+

\ No newline at end of file