Commit | Line | Data |
162a0989 |
1 | <div class="pod"> |
2 | <!-- INDEX START --> |
3 | <h3 id="TOP">Index</h3> |
4 | |
879e3e79 |
5 | <ul><li><a href="#NAME">NAME</a> |
60f74f6f |
6 | <ul><li><a href="#CATEGORY">CATEGORY</a></li> |
7 | </ul> |
8 | </li> |
ca0a3441 |
9 | <li><a href="#Creating_a_SDL_Surface_piddle">Creating a SDL Surface piddle</a> |
10 | <ul><li><a href="#Creating_a_simple_piddle">Creating a simple piddle</a></li> |
11 | <li><a href="#Operating_on_the_Surface_safely">Operating on the Surface safely</a></li> |
c7e8d3c6 |
12 | <li><a href="#Error_due_to_BPP_at_blitting">Error due to BPP at blitting</a></li> |
162a0989 |
13 | </ul> |
14 | </li> |
c7e8d3c6 |
15 | <li><a href="#AUTHORS">AUTHORS</a> |
16 | </li> |
162a0989 |
17 | </ul><hr /> |
18 | <!-- INDEX END --> |
19 | |
879e3e79 |
20 | <h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> |
21 | <div id="NAME_CONTENT"> |
22 | <p>SDL::CookBook::PDL -- CookBook for SDL + PDL</p> |
162a0989 |
23 | <p>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.</p> |
879e3e79 |
24 | |
25 | |
26 | |
27 | |
28 | |
29 | </div> |
60f74f6f |
30 | <h2 id="CATEGORY">CATEGORY</h2> |
31 | <div id="CATEGORY_CONTENT"> |
32 | <p>Cookbook</p> |
33 | |
34 | </div> |
ca0a3441 |
35 | <h1 id="Creating_a_SDL_Surface_piddle">Creating a SDL Surface piddle</h1><p><a href="#TOP" class="toplink">Top</a></p> |
36 | <div id="Creating_a_SDL_Surface_piddle_CONTEN"> |
37 | <p>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.</p> |
162a0989 |
38 | |
39 | </div> |
ca0a3441 |
40 | <h2 id="Creating_a_simple_piddle">Creating a simple piddle</h2> |
41 | <div id="Creating_a_simple_piddle_CONTENT"> |
42 | <p>First lets get the right modules.</p> |
43 | <pre> use PDL; |
44 | use SDL::Rect; |
45 | use SDL::Video; |
46 | use SDL::Surface; |
47 | use SDL::PixelFormat; |
162a0989 |
48 | |
49 | </pre> |
ca0a3441 |
50 | <p>Suppose you want a surface of size (200,400) and 32 bit (RGBA).</p> |
51 | <pre> my ( $bytes_per_pixel, $width, $height ) = ( 4, 200, 400 ); |
162a0989 |
52 | |
53 | </pre> |
ca0a3441 |
54 | <p>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;</p> |
55 | <pre> my $piddle = zeros( byte, $bytes_per_pixel, $width, $height ); |
162a0989 |
56 | |
57 | </pre> |
ca0a3441 |
58 | <p>Create a normal $piddle with zeros, byte format and the Bpp x width x height dimensions.</p> |
59 | <pre> my $pointer = $piddle->get_dataref(); |
162a0989 |
60 | |
61 | </pre> |
ca0a3441 |
62 | <p>Here is where we get the acutal data the piddle is pointing to. We will have SDL create a new surface from this function.</p> |
63 | <pre> my $surface = SDL::Surface->new_from( $pointer, $width, $height, 32, |
64 | $width * $bytes_per_pixel ); |
162a0989 |
65 | |
66 | </pre> |
ca0a3441 |
67 | <p>Using the same dimensions we create the surface using new_form. The width * Bpp is the scanline (pitch) of the surface in bytes.</p> |
68 | <pre> warn "Made surface of $width, $height and ". $surface->format->BytesPerPixel; |
69 | return ( $piddle, $surface ); |
162a0989 |
70 | |
71 | </pre> |
ca0a3441 |
72 | <p>Finally make sure that the surface acutally has the correct dimensions we gave.</p> |
73 | <p><strong>NOTE:</strong> $surface->format->BytesPerPixel must return 1,2,3,4. !!</p> |
74 | <p>Now you can blit and use the surface as needed; and do PDL operations as required.</p> |
162a0989 |
75 | |
162a0989 |
76 | |
162a0989 |
77 | |
162a0989 |
78 | |
162a0989 |
79 | |
80 | </div> |
ca0a3441 |
81 | <h2 id="Operating_on_the_Surface_safely">Operating on the Surface safely</h2> |
82 | <div id="Operating_on_the_Surface_safely_CONT"> |
83 | <p>To make sure SDL is in sync with the data. You must call SDL::Video::lock <strong>before</strong> doing PDL operations on the piddle.</p> |
84 | <pre> SDL::Video::lock_surface($surface); |
162a0989 |
85 | |
505f308d |
86 | $piddle->mslice( 'X', [ rand(400), rand(400), 1 ], [ rand(200), rand(200), 1 ] ) |
87 | .= pdl( rand(225), rand(225), rand(255), 255 ); |
162a0989 |
88 | |
89 | </pre> |
ca0a3441 |
90 | <p>After that you can unlock the surface to blit.</p> |
91 | <pre> SDL::Video::unlock_surface($surface); |
162a0989 |
92 | |
93 | </pre> |
162a0989 |
94 | |
95 | </div> |
ca0a3441 |
96 | <h2 id="Error_due_to_BPP_at_blitting">Error due to BPP at blitting</h2> |
97 | <div id="Error_due_to_BPP_at_blitting_CONTENT"> |
98 | <p>When blitting the new surface check for the return value to see if there has been a problem.</p> |
99 | <pre> my $b = SDL::Video::blit_surface( |
100 | $surface, SDL::Rect->new( 0, 0, $surface->w, $surface->h ), |
101 | $app, SDL::Rect->new( ( $app->w - $surface->w ) / 2, ( $app->h - $surface->h ) / 2, $app->w, $app->h ) |
102 | ); |
162a0989 |
103 | |
ca0a3441 |
104 | die "Could not blit: " . SDL::get_error() if ( $b == -1 ); |
162a0989 |
105 | |
106 | </pre> |
ca0a3441 |
107 | <p>If the error message is 'Blit combination not supported' that means that the BPP is incorrect or incosistent with the dimensions. |
108 | After that a simple update_rect will so your new surface on the screen.</p> |
162a0989 |
109 | |
110 | </div> |
c7e8d3c6 |
111 | <h1 id="AUTHORS">AUTHORS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
112 | <div id="AUTHORS_CONTENT"> |
1dbe1697 |
113 | <p>See <a href="/SDL.html#AUTHORS">/SDL.html#AUTHORS</a>.</p> |
c7e8d3c6 |
114 | |
115 | |
116 | |
117 | |
118 | |
119 | </div> |
162a0989 |
120 | </div> |