Doomception: Doom game launched inside Doom
An amateur created a modification of the Doom game, which adds a working slot machine with the Doom game to the game. It is noteworthy that for this he did not need to change the engine, he used the technologies already existing in the port.
The computer game Doom was released in December 1993 and became a real hit. To assess popularity, it should be mentioned that in English the phrase “first-person shooter” began to replace the term “Doom clone” only by 1996.
For that era, the game had advanced graphics, not weakly loading user processors. Today, Doom's system requirements look ridiculous due to the rapid growth of computing capabilities of all devices - almost any modern electronics is more powerful than personal computers of the early nineties. Also, the engine of the original Doom in 1999 was released under the GNU GPL license, allowing free use and change of code. The combination of these factors both allows porting Doom to various devices that are not intended for this, and gives the process a sporting interest. The game is launched on ATMs , printers , smart watches and even calculators .
This small competition has reached such a point that today it will be difficult to surprise the launch of the 1993 game on any Apple Watch. The creator of the Classic Arcade mod went further: he launched Doom right in the game. The modification does not work inside the original Doom, but the GZDoom port , first released in 2005. The mod adds a slot machine with a color screen, on which you can play Doom. Classic Arcade is not finished: the in-game versions of Doom and Wolfenstein 3D are only partially ready. In the "thought-provoking" Doom there is only one type of weapon and a number of other restrictions.
The implementation of such a modification was made possible through the use of Action Code Script. ACS, which appeared in the 1995 Hexen game, allows for the scripting of simple events: opening doors, playing sounds, and moving objects and characters in response to player actions. In ZDoom, the ACS bytecode was further developed: scripts, arrays, and entire libraries appeared. Later, advanced ACS migrated from ZDoom to GZDoom.
For mini-games, ACS has been used for at least a decade. The first samples were in-game Doomtris , clones of Arkanoid and Pac-Man . Games look like slot machines that can be controlled. But until recently, no one had implemented Doom itself on ACS inside Doom.
Topic with discussion and links to download Classic Arcade on the ZDoom forum