<div class="blog">
<h1 id="NAME">
-SDL RC 2.5 decides to play with PDL
+SDL Perl Game Contest - week 1 roundup
</h1>
<div class="CONTENT">
-<i>PDL provides great number crunching capabilities to Perl and SDL provides game-developer quality real-time bitmapping and sound.<br />
-You can use PDL and SDL together to create real-time,<br />
-responsive animations and simulations.<br />
-In this section we will go through the pleasures and pitfalls of working with both powerhouse libraries.</i> <b>-- David Mertnes</b><br />
-<br />
-<br />
-<h1>Creating a SDL Surface piddle</h1><br />
-PDL's core type is a piddle.<br />
-Once a piddle is provided to PDL it can go do a numerous amounts of things.<br />
-Please see the example in '<a href="http://github.com/kthakore/SDL_perl/blob/master/examples/cookbook/pdl.pl">examples/cookbook/pdl.pl</a>' in github.<br />
-<br />
-<h3>Creating a simple piddle</h3><br />
-First lets get the right modules.<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'> <span style='color:#e66170; font-weight:bold; '>use</span> <span style='color:#b060b0; '>PDL;</span>
- <span style='color:#e66170; font-weight:bold; '>use</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Rect</span><span style='color:#b060b0; '>;</span>
- <span style='color:#e66170; font-weight:bold; '>use</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Video</span><span style='color:#b060b0; '>;</span>
- <span style='color:#e66170; font-weight:bold; '>use</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Surface</span><span style='color:#b060b0; '>;</span>
- <span style='color:#e66170; font-weight:bold; '>use</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>PixelFormat</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-Suppose you want a surface of size (200,400) and 32 bit (RGBA).<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#e66170; font-weight:bold; '>my</span> <span style='color:#d2cd86; '>(</span> $bytes_per_pixel<span style='color:#d2cd86; '>,</span> $width<span style='color:#d2cd86; '>,</span> $height <span style='color:#d2cd86; '>)</span> <span style='color:#d2cd86; '>=</span> <span style='color:#d2cd86; '>(</span> <span style='color:#00a800; '>4</span><span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>200</span><span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>400</span> <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-Define the <b>$width</b>, <b>$height</b> and <b>$bytes_per_pixel</b>. Your <b>$bytes_per_pixel</b> is the number of bits (in this case 32) divided by 8 bits per byte. Therefore for our 32 bpp we have 4 Bpp;<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#e66170; font-weight:bold; '>my</span> $piddle <span style='color:#d2cd86; '>=</span> zeros<span style='color:#d2cd86; '>(</span> byte<span style='color:#d2cd86; '>,</span> $bytes_per_pixel<span style='color:#d2cd86; '>,</span> $width<span style='color:#d2cd86; '>,</span> $height <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-Create a normal $piddle with zeros, byte format and the Bpp x width x height dimensions.<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#e66170; font-weight:bold; '>my</span> $pointer <span style='color:#d2cd86; '>=</span> $piddle<span style='color:#d2cd86; '>-></span>get_dataref<span style='color:#d2cd86; '>(</span><span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-Here is where we get the acutal data the piddle is pointing to. We will have SDL create a new surface from this function.<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#e66170; font-weight:bold; '>my</span> $surface <span style='color:#d2cd86; '>=</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Surface</span><span style='color:#d2cd86; '>-></span>new_from<span style='color:#d2cd86; '>(</span> $pointer<span style='color:#d2cd86; '>,</span> $width<span style='color:#d2cd86; '>,</span> $height<span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>32</span><span style='color:#d2cd86; '>,</span>
- $width <span style='color:#d2cd86; '>*</span> $bytes_per_pixel <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-Using the same dimensions we create the surface using <b>SDL::Surface->new_form()</b>. The <b>$width * $Bpp</b> is the scanline (pitch) of the surface in bytes.<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#e66170; font-weight:bold; '>warn</span> <span style='color:#00c4c4; '>"Made surface of </span><span style='color:#00c4c4; '>$width</span><span style='color:#00c4c4; '>, </span><span style='color:#00c4c4; '>$height</span><span style='color:#00c4c4; '> and "</span><span style='color:#d2cd86; '>.</span> $surface<span style='color:#d2cd86; '>-></span>format<span style='color:#d2cd86; '>-></span>BytesPerPixel<span style='color:#b060b0; '>;</span>
- <span style='color:#e66170; font-weight:bold; '>return</span> <span style='color:#d2cd86; '>(</span> $piddle<span style='color:#d2cd86; '>,</span> $surface <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-Finally make sure that the surface acutally has the correct dimensions we gave.<br />
-<br />
-<b>NOTE:</b> <b>$surface->format->BytesPerPixel</b> must return 1,2,3,4. !!<br />
-<br />
-Now you can blit and use the surface as needed; and do PDL operations as required.<br />
-<br />
-<h3>Operating on the Surface safely</h3><br />
-To make sure SDL is in sync with the data. You must call SDL::Video::lock <b>before</b> doing PDL operations on the piddle.<br />
-<br />
-<pre><pre style='color:#d1d1d1;background:#000000;'><span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Video</span><span style='color:#d2cd86; '>:</span><span style='color:#d2cd86; '>:</span>lock_surface<span style='color:#d2cd86; '>(</span>$surface<span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-
- $piddle <span style='color:#d2cd86; '>(</span> <span style='color:#d2cd86; '>:</span><span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>0</span> <span style='color:#d2cd86; '>:</span> <span style='color:#e66170; font-weight:bold; '>rand</span><span style='color:#d2cd86; '>(</span><span style='color:#00a800; '>400</span><span style='color:#d2cd86; '>)</span><span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>0</span> <span style='color:#d2cd86; '>:</span> <span style='color:#e66170; font-weight:bold; '>rand</span><span style='color:#d2cd86; '>(</span><span style='color:#00a800; '>200</span><span style='color:#d2cd86; '>)</span> <span style='color:#d2cd86; '>)</span> <span style='color:#d2cd86; '>.</span><span style='color:#d2cd86; '>=</span> pdl<span style='color:#d2cd86; '>(</span> <span style='color:#e66170; font-weight:bold; '>rand</span><span style='color:#d2cd86; '>(</span><span style='color:#00a800; '>225</span><span style='color:#d2cd86; '>)</span><span style='color:#d2cd86; '>,</span> <span style='color:#e66170; font-weight:bold; '>rand</span><span style='color:#d2cd86; '>(</span><span style='color:#00a800; '>225</span><span style='color:#d2cd86; '>)</span><span style='color:#d2cd86; '>,</span> <span style='color:#e66170; font-weight:bold; '>rand</span><span style='color:#d2cd86; '>(</span><span style='color:#00a800; '>255</span><span style='color:#d2cd86; '>)</span><span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>255</span> <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre></pre><br />
-After that you can unlock the surface to blit.<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Video</span><span style='color:#d2cd86; '>:</span><span style='color:#d2cd86; '>:</span>unlock_surface<span style='color:#d2cd86; '>(</span>$surface<span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-<h3>Errors due to BPP at blitting</h3><br />
-When blitting the new surface check for the return value to see if there has been a problem.<br />
-<br />
-<pre style='color:#d1d1d1;background:#000000;'><span style='color:#e66170; font-weight:bold; '>my</span> $b <span style='color:#d2cd86; '>=</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Video</span><span style='color:#d2cd86; '>:</span><span style='color:#d2cd86; '>:</span>blit_surface<span style='color:#d2cd86; '>(</span>
- $surface<span style='color:#d2cd86; '>,</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Rect</span><span style='color:#d2cd86; '>-></span>new<span style='color:#d2cd86; '>(</span> <span style='color:#00a800; '>0</span><span style='color:#d2cd86; '>,</span> <span style='color:#00a800; '>0</span><span style='color:#d2cd86; '>,</span> $surface<span style='color:#d2cd86; '>-></span>w<span style='color:#d2cd86; '>,</span> $surface<span style='color:#d2cd86; '>-></span>h <span style='color:#d2cd86; '>)</span><span style='color:#d2cd86; '>,</span>
- $app<span style='color:#d2cd86; '>,</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>Rect</span><span style='color:#d2cd86; '>-></span>new<span style='color:#d2cd86; '>(</span> <span style='color:#d2cd86; '>(</span> $app<span style='color:#d2cd86; '>-></span>w <span style='color:#d2cd86; '>-</span> $surface<span style='color:#d2cd86; '>-></span>w <span style='color:#d2cd86; '>)</span> <span style='color:#d2cd86; '>/</span> <span style='color:#00a800; '>2</span><span style='color:#d2cd86; '>,</span> <span style='color:#d2cd86; '>(</span> $app<span style='color:#d2cd86; '>-></span>h <span style='color:#d2cd86; '>-</span> $surface<span style='color:#d2cd86; '>-></span>h <span style='color:#d2cd86; '>)</span> <span style='color:#d2cd86; '>/</span> <span style='color:#00a800; '>2</span><span style='color:#d2cd86; '>,</span> $app<span style='color:#d2cd86; '>-></span>w<span style='color:#d2cd86; '>,</span> $app<span style='color:#d2cd86; '>-></span>h <span style='color:#d2cd86; '>)</span>
- <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-
- <span style='color:#e66170; font-weight:bold; '>die</span> <span style='color:#00c4c4; '>"Could not blit: "</span> <span style='color:#d2cd86; '>.</span> <span style='color:#904050; '>SDL</span><span style='color:#d2cd86; '>::</span><span style='color:#904050; '>get_error</span><span style='color:#d2cd86; '>(</span><span style='color:#d2cd86; '>)</span> <span style='color:#e66170; font-weight:bold; '>if</span> <span style='color:#d2cd86; '>(</span> $b <span style='color:#d2cd86; '>=</span><span style='color:#d2cd86; '>=</span> <span style='color:#d2cd86; '>-</span><span style='color:#00a800; '>1</span> <span style='color:#d2cd86; '>)</span><span style='color:#b060b0; '>;</span>
-</pre><br />
-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.<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/3102167581424744259-3580429408870545769?l=yapgh.blogspot.com' alt='' /></div>
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+As you probably know, last week we started the <a href="http://yapgh.blogspot.com/2011/02/sdl-perl-game-contest.html">SDL Perl Game Contest</a> (more like a Game Challenge, as people pointed out), where you have to write one game per week throughout the entire month of March!<br /><br />So far we had some awesome entries - people really stood up to the challenge! Check them out:<br /><br /><br /><a href="https://github.com/jtpalmer/sdl-contest/tree/master/week1">Solar Conflict</a>, by JT Palmer (jtpalmer)<br /><br /><a href="http://2.bp.blogspot.com/-O4eOSpw9_WI/TXXH2myog0I/AAAAAAAAAKg/jkybUvlZ2zM/s1600/solarflare.png"><img style="cursor: pointer; width: 400px; height: 309px;" src="http://2.bp.blogspot.com/-O4eOSpw9_WI/TXXH2myog0I/AAAAAAAAAKg/jkybUvlZ2zM/s400/solarflare.png" alt="" id="BLOGGER_PHOTO_ID_5581587054135378754" border="0" /></a><br /><br />When JT came to #sdl in the middle of the week with some bugfixes for SDLx::Controller::Interface, we knew he was up to something. <span style="font-style: italic;">Solar Conflict</span> is a brilliant clone of <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Spacewar%21">Spacewar!</a>, one of the earliest known computer games, where two spaceships battle against each other while steering clear of a star's gravity well. This version of the game lets you play against the computer or another player, and all graphics were taken from <a href="http://opengameart.org/">Open Game Art</a>. Funny fact: the initial version of the original <span style="font-style: italic;">Spacewar!</span> game took approximately 200 hours to be created. Way to go, JT!<br /><br /><br /><a href="https://github.com/PerlGameDev/Asteroids">Asteroids</a>, by Tobias Leich (FROGGS)<br /><br /><a href="http://1.bp.blogspot.com/-zM36VHBoyCQ/TXXVfPt9VkI/AAAAAAAAAKw/Pgj0skkg0I4/s1600/asteroids.png"><img style="cursor: pointer; width: 400px; height: 235px;" src="http://1.bp.blogspot.com/-zM36VHBoyCQ/TXXVfPt9VkI/AAAAAAAAAKw/Pgj0skkg0I4/s400/asteroids.png" alt="" id="BLOGGER_PHOTO_ID_5581602045967554114" border="0" /></a><br /><br />Speaking of spaceships and classic remakes, who doesn't remember <a href="http://en.wikipedia.org/wiki/Asteroids_%28video_game%29">Asteroids</a>? This Atari masterpiece served as inspiration to FROGGS this week, and he provided a beautifully crafted clone, taking you back to the golden age of arcade games.<br /><br /><br /><a href="https://github.com/kthakore/SDL_Contest/tree/master/first">Polyzle</a>, by Kartik Thakore (kthakore)<br /><br /><a href="http://2.bp.blogspot.com/-IkFIkFWAlmk/TXXVsaxVnnI/AAAAAAAAAK4/Q2oCPUkWjTQ/s1600/polyzle.png"><img style="cursor: pointer; width: 400px; height: 312px;" src="http://2.bp.blogspot.com/-IkFIkFWAlmk/TXXVsaxVnnI/AAAAAAAAAK4/Q2oCPUkWjTQ/s400/polyzle.png" alt="" id="BLOGGER_PHOTO_ID_5581602272272817778" border="0" /></a><br /><br />But enough of rethinking the past - Kartik pushed the limits of <span style="font-style: italic;">avant-garde</span> this week and brought us Polyzle (or "Polygon Trouble"). The player is faced with several colored polygons swarming around the screen, and needs to click on them to score points - but only has 30 seconds to do it, and believe me, it's not as easy as it looks! While the game certainly doesn't fit the usual rationalities of a standard gameplay, Kartik replies that maybe his game is just too ahead of its time. What do you think? Could he be the Van Gogh of game design? Only time will tell ;-)<br /><br /><br /><a href="https://github.com/PerlGameDev/Games-FingerTwister">FingerTwister</a>, by... me =P (garu)<br /><br /><a href="http://2.bp.blogspot.com/-_cPXtcpOFYQ/TXXKgiGIWHI/AAAAAAAAAKo/ggRdCVEEGPw/s1600/fingertwister.png"><img style="cursor: pointer; width: 400px; height: 312px;" src="http://2.bp.blogspot.com/-_cPXtcpOFYQ/TXXKgiGIWHI/AAAAAAAAAKo/ggRdCVEEGPw/s400/fingertwister.png" alt="" id="BLOGGER_PHOTO_ID_5581589973452740722" border="0" /></a><br /><br />Last but not least, my precioussssssss.... FingerTwister! In this game, the player needs to press the keys on the keyboard as they show up on screen, and <span style="font-weight: bold;">keep them pressed</span> as new keys appear. You can only let go the keys<span style="font-style: italic;"> after</span> they disappear from the screen, and the sooner you press a key (the green bar on the bottom) the more points you get. The game also features music and sound effects from talented artists at <a href="http://ccmixter.org/">ccMixter</a> and <a href="http://freesound.org/">FreeSound</a>, and a highscore table. Unfortunately, as any game that requires multiple keys pressed at the same time, it suffers from key-jamming issues on regular (plain) keyboards. I tried to provide a workaround for that, but the only real solution is getting a n-key rollover keyboard like razerzone's and logitech's G15/G19.<br /><br />Overall, I'm really happy about this week's roundup of games, and we're still receiving submissions! Perl coder or not, if you always wanted to write a computer game, join us on the SDL Perl Game Contest, and we'll help you take it out of your TODO list and into the glory it deserves!<br /><br />See you next week =)<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/3102167581424744259-1440981436339915214?l=yapgh.blogspot.com' alt='' /></div>
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