<story><title>Commander Keen source code released</title><url>https://github.com/keendreams/keen</url></story><parent_chain><item><author>Arjuna</author><text>A little slice of history regarding one of the technical foundations of Commander Keen, for those that aren&amp;#x27;t aware:&lt;p&gt;&amp;quot;Then, the first breakthrough. John Carmack devised a smooth, scrolling routine similar to that used for the background of Nintendo games but never before possible on the PC.&amp;quot; [1]&lt;p&gt;The technique is called, &lt;i&gt;adaptive tile refresh.&lt;/i&gt; [2]&lt;p&gt;[1] &lt;a href=&quot;http://www.3drealms.com/keenhistory&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;www.3drealms.com&amp;#x2F;keenhistory&lt;/a&gt;&lt;p&gt;[2] &lt;a href=&quot;https://en.wikipedia.org/wiki/Adaptive_tile_refresh&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Adaptive_tile_refresh&lt;/a&gt;</text></item></parent_chain><comment><author>vidarh</author><text>It&amp;#x27;s fascinating that this was something new on the PC that late.&lt;p&gt;This is roughly how most scrolling on the C64 happens (though it works by &lt;i&gt;reducing&lt;/i&gt; the visible display by 8 hires pixels on either side of the screen, and scrolling at most 8 hires pixels before you need to shift &amp;quot;tiles&amp;quot; &amp;#x2F; characters). I&amp;#x27;m not sure it was new with the C64 either. While most C64 games used sprites for the movable objects, there are absolutely exceptions that tracked damage.&lt;p&gt;On the Amiga, however, the method described is basically pretty much how you&amp;#x27;re expected to do scrolling from the outset(it has much more extensive support for it than EGA did). AmigaOS even came with built in support for managing damage lists for such objects (&amp;quot;bobs&amp;quot; for &amp;quot;blittable objects&amp;quot;) and double buffering from 1985, though most games would have used their own code for it.&lt;p&gt;For these systems redrawing the whole screen was simply never seen as viable, or worthwhile. The Amiga hardware support for doing this kind of scrolling + the use of the blitter for moving game objects and replacing damaged sections made this method the obvious choice.&lt;p&gt;Even double-buffering was sometimes seen as too wasteful, with a solution being to sort damage lists and tie updates to the raster interrupt to update the screen before the raster beam reached it.</text></comment>
<story><title>Commander Keen source code released</title><url>https://github.com/keendreams/keen</url></story><parent_chain><item><author>Arjuna</author><text>A little slice of history regarding one of the technical foundations of Commander Keen, for those that aren&amp;#x27;t aware:&lt;p&gt;&amp;quot;Then, the first breakthrough. John Carmack devised a smooth, scrolling routine similar to that used for the background of Nintendo games but never before possible on the PC.&amp;quot; [1]&lt;p&gt;The technique is called, &lt;i&gt;adaptive tile refresh.&lt;/i&gt; [2]&lt;p&gt;[1] &lt;a href=&quot;http://www.3drealms.com/keenhistory&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;www.3drealms.com&amp;#x2F;keenhistory&lt;/a&gt;&lt;p&gt;[2] &lt;a href=&quot;https://en.wikipedia.org/wiki/Adaptive_tile_refresh&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Adaptive_tile_refresh&lt;/a&gt;</text></item></parent_chain><comment><author>sprokolopolis</author><text>I remember reading in &lt;i&gt;Masters of Doom&lt;/i&gt; that they had actually asked Nintendo if they could license games to get them on personal computers, Obviously, Nintendo declined. They were able to get the first level of Super Mario Bros running on personal computers and used that method in the Commander Keen series.</text></comment>