Editing Jumpman (video game) (section)

==Development==
Randy Glover was living in [[Foster City, California]] and had been experimenting with [[electronics]] when he saw his first computer in 1977 when he played [[Star Trek (1971 video game)|''Star Trek'']] at a [[Berkeley, California|Berkeley]] [[university]] open house.{{sfn|Glover|loc=3:00}} This prompted him to purchase a [[Commodore PET]] in 1978{{sfn|Glover|loc=4:00}}{{efn|Glover refers to this as a VIC-20, but this was not introduced until some years later.}} and then upgrade to a [[TRS-80]] due to its support of a [[hard disk drive|hard drive]].{{sfn|Glover|loc=5:00}}

''Jumpman'' came about after Glover saw ''[[Donkey Kong (1981 video game)|Donkey Kong]]''<ref>{{cite journal |first=Darryl |last=Guenther |title=Doin' the Donkey Kong |journal=Classic Gamer Magazine |date=Fall 1999 |page=20 |url=http://www.digitpress.com/library/magazines/cgm/cgm_1.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.digitpress.com/library/magazines/cgm/cgm_1.pdf |archive-date=2022-10-09 |url-status=live}}</ref><ref>{{cite web |url=http://home.arcor.de/cybergoth/gamesa/jumpinterview1.html |title=I talked to Randy Glover about Jumpman. |archive-url=https://web.archive.org/web/20080115074357/http://home.arcor.de/cybergoth/gamesa/jumpinterview1.html | archive-date=15 January 2008 |access-date=3 June 2007}}</ref> in a local [[Pizza Hut]].{{sfn|Glover|loc=10:30}} This led him to become interested in making a version for [[home computer]]s. He visited a local computer store who had the [[TI-99/4A]] and Atari 400. He initially purchased the TI-99 due to its better keyboard,{{sfn|Glover|loc=12:30}} but when he learned the graphics were based on [[character set]] manipulation, he returned it the next day and purchased the Atari.{{sfn|Glover|loc=11:30}}

The initial version was written by Albert Persinger, using a compiler on the [[Apple II]], moving the software to the Atari. A prototype with 13 levels took four or five months to complete. After looking in the back of a computer magazine for publisher, in early 1983 he approached [[Broderbund]].{{sfn|Glover|loc=14:00}} They were interested but demanded that their programmers be allowed to work on it. The next day he met with Automated Simulations, who were much more excited by the game and agreed to allow Glover to complete it himself.{{sfn|Glover|loc=15:00}}

At the time, the company was in the process of moving from the [[strategy game]] market to action titles, which they released under their Epyx brand. ''Jumpman'' was the perfect title for the brand, and the company hired him.{{sfn|Glover|loc=15:45}} Aiming the game at the newly enlarged RAM available on the Atari 800 led to the 32 levels of the final design.{{sfn|Glover|loc=18:00}} The Atari release was a huge hit, and the company soon abandoned their strategic games and renamed as Epyx.<ref>{{cite web |url=http://thedoteaters.com/?bitstory=epyx |title= Epyx Journey |website=The Dot Eaters}}</ref> Glover then moved on to a C64 port, which was not trivial due to a particular feature of the Atari hardware Glover used to ease development.{{sfn|Glover|loc=48:45}}

[[Image:64jumpman.gif|thumb|The C64 port has an improved Jumpman sprite, but is otherwise similar to the Atari version.]]

Other programmers at Epyx ported it to the Apple II, with poor results,{{sfn|Glover|loc=52:15}} and, a year later, contracted Mirror Images Software for an IBM PC/PCjr port. The Atari and Commodore versions were released on disk and cassette tape, the Apple and IBM versions only on disk. The Atari version used a classic [[bad sector|bad-sector]] method of preventing copying, but this had little effect on [[software piracy|piracy]].{{sfn|Glover|loc=39:30}}

After developing the original versions, Glover moved on to ''Jumpman Junior'', a cartridge title with only 12 levels. He stated that it wasn't really a sequel to ''Jumpman'', but more of a "lite" version for Atari and Commodore users who didn't have disk drives. These versions removed the more complex levels and any code needed to run them.{{sfn|Glover|loc=48:00}} Two of its levels (Dumbwaiter and Electroshock Traps) were turned into Sreddal ("Ladders" backwards) and Fire! Fire! on the latter. The C64 version was later ported to the ColecoVision, which used the C64 levels.{{sfn|Glover|loc=53:00}}

Glover continued working at Epyx, working on the little-known ''Lunar Outpost'' and the swimming section of ''[[Summer Games (video game)|Summer Games]]''. He remained at the company for about two years{{sfn|Glover|loc=49:00}} before returning to the [[cash register]] business.{{sfn|Glover|loc=1:06:00}}

===Technical details===
Movement was controlled through the [[collision detection]] system of the Atari's [[Sprite (computer graphics)|player/missile graphics]] hardware. This system looks for overlap between the sprites and the background, setting [[Processor register|registers]] that indicate which sprite had touched which color.<ref>{{cite book |first= Chris |last=Crawford |title= De Re Atari | publisher =Atari Program Exchange |date= 1982 |chapter= Hardware Collision Detection |url= http://www.atariarchives.org/dere |chapter-url=http://www.atariarchives.org/dere/chapt04.php#H4_8}}</ref>

Glover separated the Jumpman [[sprite (computer graphics)|sprite]] into two parts, the body and the feet. By examining which of these collided, the engine could determine which direction to move. For instance, if both the body and feet collided with the same color, it must be a wall, and the Jumpman should stop moving. If there was no collision with either his feet or body, Jumpman is unsupported and should fall down the screen. Variations on these allowed support for ramps, ropes, and other features.{{sfn|Glover|loc=20:00}}

This not only saved processing time comparing the player location to an in-memory description of the map, but also meant that maps could be created simply by drawing with them and experimenting with the results in the game.{{sfn|Glover|loc=22:00}}