pods::...k::PDL(3pm)

✨ NAME ✨

okay so this is pods::...k::PDL(3pm), coming at you from the User Contributed Perl Documentation, and its actual NAME is SDL::CookBook::PDL — CookBook for SDL + PDL. 💖

PDL is out here giving Perl great number-crunching capabilities, while SDL brings game-developer quality real-time bitmapping and sound. Use PDL and SDL ''together'' and you can create real-time, responsive animations and simulations. This section is all about the pleasures and pitfalls of working with both powerhouse libraries. ✨

🎀 CATEGORY 🎀

Cookbook — that's the category. 📚

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🦋 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' that came with this module. 👀

🍓 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 actual 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 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 actually 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->mslice( 'X', [ rand(400), rand(400), 1 ], [ rand(200), rand(200), 1 ] )
    .= pdl( rand(225), rand(225), rand(255), 255 );

After that you can unlock the surface to blit. 🔓

SDL::Video::unlock_surface($surface);

🔥 Error 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 inconsistent with the dimensions. After that a simple update_rect will so your new surface on the screen. 💀

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👑 AUTHORS 👑

See "AUTHORS" in SDL. 🫶

okay that's the whole page, bestie 💅 — footer tea: this is perl v5.42.3, dated 2026-08-19, and the page is pods::...k::PDL(3pm). mwah 🫶