Path: csiph.com!news.mixmin.net!aioe.org!.POSTED!not-for-mail From: Kaz Kylheku <545-066-4921@kylheku.com> Newsgroups: comp.programming Subject: Re: Mystified by an Atari 2600 demo. Date: Thu, 9 Jun 2016 00:01:38 +0000 (UTC) Organization: Aioe.org NNTP Server Lines: 18 Message-ID: <20160608165646.591@kylheku.com> References: <23c1e131-543c-4654-85b0-f3876f484635@googlegroups.com> NNTP-Posting-Host: OGJi3KNpFOhM58UHZwXj0w.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Complaints-To: abuse@aioe.org User-Agent: slrn/pre1.0.0-18 (Linux) X-Notice: Filtered by postfilter v. 0.8.2 Xref: csiph.com comp.programming:6678 On 2016-06-08, Chad wrote: > > In the demo, the guy enters the coordinates(?) to a sprite. Right > after that, this sprite then gets displayed on a screen. Right after > that, he is able to do things like type text and clear the screen. > This is done without impacting the sprite.  By the way, this is why those things are called sprites! They are like ghosts. In popular culture, ghosts can appear to people in their visual field, but don't interact with objects. They go through walls and so on. Your PC probably has a sprite: namely, the hardware-based mouse cursor! A hardware-based mouse cursor can stay on the screen and appear smooth no matter what is happening. Rectangular copies of the frame buffer from one place to another are oblivious to it, etc.