ID24

ID24 is a specification and standard specifically aimed at mod authors and mods in general. It builds on top of the possibilities shown in the MBF21 standard, acting as a super-set of it, and was first implemented in the KEX Engine source port of Doom + Doom II. It was first used there for the Legacy of Rust episode.

History

Initially under development in Rum and Raisin Doom under the name 'RNR24', Doom + Doom II licensed the code and renamed it to 'ID24'. On August 10, 2024 documentation for the standard, titled "ID24 0.99.1" in the files, was released on Google Drive.

Neither the specification 'ID24 0.99.1' nor Doom + Doom II at release are fully compatible with Boom and MBF21 standards, this is due to it being a clean-room re-implementation. Where the ID24 code (all the new tech features) is open to be adopted to source ports, the resources file requires that if you want to use the new monsters, id24res.wad needs to be included.

On August 13, 2024, Simon Howard (Fraggle) announced that the Freedoom project would develop a free replacement for id24res.wad, as part of a subproject named 'FD24', with a branch on the official GitHub repository being created the same day. This will allow any future mods developed against the new ID24 standard to remain playable under Freedoom.

On September 4, 2024 Ethan Watson (GooberMan) announced a draft revision of the spec 'ID24 0.99.2', clarifying that the documents are CC0, with the code being GPL. It revised the wording for id24res.wad, added a self damage factor to ID24HACKED, while ability to apply a translation to every graphic asset in a WAD has been added to GAMECONF, as well as many revisions in the wording in the documentation.

The finalized spec will follow soon.

Features

An overview of most of the ID24 features and some Boom oddities.

• Several new things, including new monsters and props, internally defined with ID24HACKED features.
• Several new control lumps, using JSON format. These include notably:
  • DEMOLOOP to define custom demo loops, which was previously a hard-coded feature;
  • GAMECONF to define general information about a WAD file;
  • SBARDEF to define status bars;
  • SKYDEFS to define skies.
• Uses the UMAPINFO standard, with some new additions, such as the ability to define intermission scripts with the enteranim and exitanim properties (using lumps in JSON format as the values).

Mapping additions

ID24 has implemented a few new features and line specials for use by mappers. This section details this new functionality.

Baseline features

The ID24 map additions are a super-set of the following specifications:

• The vanilla Doom features
• Boom
• MUSINFO
• MBF
• DEHEXTRA
• MBF21
• DSDHacked
• UMAPINFO

An ID24-capable port is expected to implement all features for those standards.

Reserved indices for line specials

The following line special index ranges are reserved for future use by id Software and/or its affiliates:

• 2048 - 4095 inclusive

This is easily testable with a bitwise AND with single bit, 0x0800. Any line special outside of the Boom generalised linedef range with this bit set is expected to have been defined by id Software and/or its affiliates; if it has been defined through any other means, this is in violation of the ID24 specification.

Further, the line specials used by ZokumBSP are respected and reserved for use by ZokumBSP. At the time of writing, the following list of indices are reserved:

• 998
• 999
• 1048
• 1078
• 1079
• 1080
• 1081
• 1082
• 1083
• 1084
• 1085
• 1086

UMAPINFO additions

UMAPINFO defines the bossaction field as a way to activate a line special when all boss monsters of the specified type are killed. It uses a string mnemonic to resolve the type. This was reasonable when it was not possible to have four billion+ different types. As such, bossaction now allows you to specify the thing number as defined by DeHackEd in place of a string mnemonic.

Further, bossactionednum has been added which differs from bossaction by resolving a thing's editor number instead of the thing number directly. The boss actions internally still use the usual thing type values, and as such this field must resolve to a valid thing from the editor number to be able to function correctly.

Any texture and flat can be used on any surface

ID24 allows both textures defined in TEXTURE1/2 and flats found between flat markers in the WAD directory to be rendered on any floor, ceiling, or wall. TEXTURE1/2 textures rendered on floors and ceilings do not clamp to power-of-2 boundaries but instead render their entire dimensions in a 1:1 ratio of texels to world units. TEXTURE1/2 textures rendered on floors and ceilings tile using the same rules as flats.

For the purposes of rendering a transparent texture on a solid surface, transparent texels must be rendered with palette index 0. Composite textures must clear their texture to palette index 0 before compositing.

Floor and ceiling texture transformations

There are now line specials to offset floor and ceiling textures, similar to how wall textures are offset. The line special's X and Y direction are treated as the offset values. Offsets are always applied assuming the floor/ceiling is rendering from the origin (0, 0).

Floor and ceiling textures are also rotatable. As per offsets, the rotation is defined by the angle of the line and applied as if the floor/ceiling is rendering from the origin (0, 0). Lines that combine offset and rotation effects perform the offset first and then the rotation.

ID	Usage	Description
2048	Always	Offset target floor texture by line direction
2049	Always	Offset target ceiling texture by line direction
2050	Always	Offset target floor and ceiling texture by line direction
2051	Always	Rotate target floor texture by line angle
2052	Always	Rotate target ceiling texture by line angle
2053	Always	Rotate target floor and ceiling texture by line angle
2054	Always	Offset then rotate target floor texture by line direction and angle
2055	Always	Offset then rotate target ceiling texture by line direction and angle
2056	Always	Offset then rotate target floor and ceiling texture by line direction and angle

Music changing

The new music line specials mean that you no longer are required to use MUSINFO to change the current music track playing. When defining the music track, you set the upper texture to the wanted lump name of the music track when activating the line from the front side; and the lower texture when activating from the back side. The music change is immediate, unlike MUSINFO which has a small delay.

If a lump is not found with the provided name, no music change occurs.

If the upper/lower textures are not set, no music change occurs. The exception is when using the "reset" class of lines, which reverts to the level's default looping music when activated.

ID	Usage	Description
2057	W1	Change music and make it loop only if a track is defined
2058	WR	Change music and make it loop only if a track is defined
2059	S1	Change music and make it loop only if a track is defined
2060	SR	Change music and make it loop only if a track is defined
2061	G1	Change music and make it loop only if a track is defined
2062	GR	Change music and make it loop only if a track is defined
2063	W1	Change music and make it play only once
2064	WR	Change music and make it play only once
2065	S1	Change music and make it play only once
2066	SR	Change music and make it play only once
2067	G1	Change music and make it play only once
2068	GR	Change music and make it play only once
2087	W1	Change music and make it loop, reset to looping default if no track defined
2088	WR	Change music and make it loop, reset to looping default if no track defined
2089	S1	Change music and make it loop, reset to looping default if no track defined
2090	SR	Change music and make it loop, reset to looping default if no track defined
2091	G1	Change music and make it loop, reset to looping default if no track defined
2092	GR	Change music and make it loop, reset to looping default if no track defined
2093	W1	Change music and make it play only once, reset to looping default if no track defined
2094	WR	Change music and make it play only once, reset to looping default if no track defined
2095	S1	Change music and make it play only once, reset to looping default if no track defined
2096	SR	Change music and make it play only once, reset to looping default if no track defined
2097	G1	Change music and make it play only once, reset to looping default if no track defined
2098	GR	Change music and make it play only once, reset to looping default if no track defined

Reset exits

Lines are provided that reset the player's inventory after exiting a map. This removes the requirements for death exits to do such things; and also allows a cleaner way of handling such setups as Eviternity's secret maps rewarding the player with not resetting their inventory on entering MAP16 (i.e. place the reset exit on MAP15 and the flow is preserved naturally since the reset happens at map end instead of map start).

ID	Usage	Description
2069	W1	Exit to the next map and reset inventory
2070	S1	Exit to the next map and reset inventory
2071	G1	Exit to the next map and reset inventory
2072	W1	Exit to the secret map and reset inventory
2073	S1	Exit to the secret map and reset inventory
2074	G1	Exit to the secret map and reset inventory

Sector tinting

Sectors can now have colormaps applied directly to them without needing to use Boom's property transfer line specials. It is also possible to do this dynamically thanks to interactive line special types. When defining the COLORMAP, you set the upper texture to the wanted lump name of the COLORMAP when using the static special or when activating the line from the front side; and the lower texture when activating from the back side.

If a lump is not found with the provided name, or if the upper/lower textures are not set, the sector's COLORMAP is cleared and it uses the current default COLORMAP (as set with the property transfer zone you are in).

When a sector's COLORMAP is set this way, it entirely overrides the default COLORMAP (including property transfers, excluding powerups).

ID	Usage	Description
2075	Always	Set the target sector's colormap
2076	W1	Set the target sector's colormap
2077	WR	Set the target sector's colormap
2078	S1	Set the target sector's colormap
2079	SR	Set the target sector's colormap
2080	G1	Set the target sector's colormap
2081	GR	Set the target sector's colormap

Scrolling textures

New special types have been added to scroll both the front and the back sidedefs of a line in the same cardinal direction. The defined direction is relative to the front sidedef of a line.

ID	Usage	Description
2082	Always	Scroll both front and back sidedef's textures according to the line's left direction
2083	Always	Scroll both front and back sidedef's textures according to the line's right direction
2084	Always	Scroll both front and back sidedef's textures according the target sector's scroll values divided by 8
2085	Always	Scroll both front and back sidedef's textures according the target sector's movement divided by 8
2086	Always	Scroll both front and back sidedef's textures and accelerate the scroll value by the target sector's movement divided by 8

New things

Monsters

ID	Name	Sprite
-28672	Ghoul	GHUL
-28671	Banshee	BSHE
-28670	Mindweaver	CSPI
-28669	Shocktrooper	PPOS
-28668	Vassago	VASS
-28667	Tyrant	CYB2
-28666	Tyrant (Boss 1)	CYB2
-28665	Tyrant (Boss 2)	CYB2

Decorations

ID	Name	Sprite
-28663	Large corpse pile	POL7A0
-28662	Human BBQ 1	HBBQ
-28661	Human BBQ 2	HBB2
-28660	Hanging victim, both legs	GOR6A0
-28659	Hanging victim, both legs (blocking)	GOR6A0
-28658	Hanging victim, crucified	GOR7A0
-28657	Hanging victim, crucified (blocking)	GOR7A0
-28656	Hanging victim, arms bound	GOR8A0
-28655	Hanging victim, arms bound (blocking)	GOR8A0
-28654	Hanging baron of hell	GORAA0
-28653	Hanging baron of hell (blocking)	GORAA0
-28652	Hanging victim, chained	HDB7A0
-28651	Hanging victim, chained (blocking)	HDB7A0
-28650	Hanging torso, chained	HDB8A0
-28649	Hanging torso, chained (blocking)	HDB8A0
-28648	Skull pole trio	POB6A0
-28647	Skull gibs	POLAA0
-28646	Bush, short	BSH1A0
-28645	Bush, short burned 1	BSH1B0
-28644	Bush, short burned 2	BSH1C0
-28643	Bush, tall	BSH2A0
-28642	Bush, tall burned 1	BSH2B0
-28641	Bush, tall burned 2	BSH2C0

Obstacles

ID	Name	Sprite
-28664	Stalagmite (gray)*	SMT2A0
-28640	Cave rock column	STMIA0
-28639	Cave stalagmite, large	STG1A0
-28638	Cave stalagmite, medium	STG2A0
-28637	Cave stalagmite, small	STG3A0
-28636	Cave stalactite, large	STC1A0
-28635	Cave stalactite, large (blocking)	STC1A0
-28634	Cave stalactite, medium	STC2A0
-28633	Cave stalactite, medium (blocking)	STC2A0
-28632	Cave stalactite, small	STC3A0
-28631	Cave stalactite, small (blocking)	STC3A0
-28630	Office chair	CHR1

* Sprite located in Doom/Doom II IWAD

Light sources

ID	Name	Sprite
-28629	Office lamp (breakable)	LAMP
-28628	Ceiling lamp	TLP6A0
-28627	Candelabra (short)	CBR2A0

Sounds

ID	Name
-28626	Ambient klaxon
-28625	Ambient portal open
-28624	Ambient portal loop
-28623	Ambient portal close

Ammunition

ID	Name	Sprite
-28622	Fuel can	FCPUA0
-28621	Fuel tank	FTNKA0

Weapons

ID	Name	Sprite
-28620	Heatwave generator	CBLDA0
-28619	Incinerator	INCNA0

Supported ports

Support for the ID24 specification is implemented in the following source ports:

• Doom + Doom II
• GZDoom (partial support as of version 4.13)
• Helion (partial support as of version 0.9.5.0)
• Woof (partial support as of version 15.0.0)
• Odamex (partial support as of version 11.0.0)

Files

• id24res.wad - Resources

Credits

The ID24 spec was developed in a collaborative effort with various members of the community. The core team responsible for the spec included the following members:

• Ethan Watson (GooberMan)
  • Main programmer
• Xaser
  • State/thing/etc tables, DECOHACK
  • Front+back linedef scrollers, bugfixes, general QA/feedback on the spec wordings

Trivia

• ID24 is referenced in WADINFO lump of Legacy of Rust, the first public use of the term.

See also

• MBF21

External links

• ID24 0.99.1 specifications hosted on Google Drive
• ID24 0.99.2 draft specifications hosted on Google Drive
• GooberMan's WAD Demonstrating new features hosted on GitHub