Xargon is now open source, and the released code has also been useful in reverse engineering Jill of the Jungle.
The following tools are able to work with this game.
|Xargon open source||SDL (Linux/Mac/Win)||N/A||Edit||No||No||No||No||No||No|
This section lists the major file formats used in the game. The file extensions .xr refer to a specific episode - this will be .xr1 to .xr3, and .xr0 for a "global" file that is used by all episodes.
|config.xr||Configuration file in CFG Format (Jill of the Jungle)|
|song_*.xr||Music in CMF Format|
|tiles.xr||Tile information in DMA Format|
|Game levels in Jill of the Jungle Map Format. map.* are the overhead maps, demo* are the demo levels, intro.* are the main menu backgrounds and story.* are the backgrounds behind the in-game story screens. The overhead map is saved into board_t.xr when entering a level, so that it can be restored when the level is complete (so this file is regularly overwritten by the game.)|
|*_mac.xr||Input macros for demos in MAC Format (Jill of the Jungle)|
|graphics.xr||Shapes (images) in SHA Format|
|audio.xr||Digitised sound and PC speaker effects in VCL Format|
|save_[0-9].xr||Saved games - just dumps of the entire level in its current state (same format as actual levels)|
|screen_.xr0||Images used for episode selection menu, in PCX Format|
|screen_3.xr0||B800 Text screen shown after quitting the episode selection menu|
A palette is also located at offset 0x26b32 in each episode's .exe file (i.e. xrfile0.exe.) The offset is the same for each episode, and there is only one known version of each file. The palette is 768 bytes long in 6-bit VGA format. This palette however, does not appear to be used, and is likely a leftover from Jill of the Jungle. The game's main palette is stored in graphics.xr as tile #0 in tileset #5. (There is also another palette in tileset #53, tile #0, but its purpose is currently unknown.)
- The text image shown during init (when detecting and configuring hardware) is stored inside the .exe in "TheDraw Crunched Screen Image" format. At first glance this appears to be a relatively simple RLE-based format. It appears to be the only type of compression used throughout the entire game, so reverse engineering it is perhaps not so important. (The decompression code was not included in the source release.)
- There is an undocumented "/TEST" parameter which will show the detected CPU speed as a number on the hardware detection screen. According to the source code, an 8MHz 286 gives a value of 5452, a 16MHz 386 is 17819, and a 33MHz 386 is 36392.
- The one publicised cheat code (press F7 three times) has a secondary condition which will activate a debug mode when the Z key is pressed three times. All debug mode seems to do is replace the yellow high score number with a blue number representing the amount of free memory.
- There are keycode printing functions ('W' three times) and macro (demo) recording functions (R to start, E to end) and some sort of game editor (Ctrl+E), however the code for these was commented out for the commercial release.
Allen Pilgrim released Xargon as freeware on 4 August 2008, and included the source code in the release. It can be downloaded from the Classic DOS Games archive.
- Jill of the Jungle - the forerunner to Xargon (which shares many similarities and file formats)