Switches are implemented using wall texture names that are built-in to the Doom rendering engine. At initialization time, the engine finds each texture name listed in the “Off” column below (in the TEXTURE1 or TEXTURE2 lump), and links it with the name in the “On” column. When a linedef using a switch texture has a type that can be activated, the texture is replaced by its counterpart when used. If the line effect can be repeated, the switch keeps its alternate texture for a full second, before reverting to its initial appearance; internally, repeatable switches are referred to as buttons. Switches play the sound DSSWTCHN when activated, and DSSWTCHX when resetting. Exit switches play DSSWTCHX.
Switches can be activated by pressing USE key in range less than 48 map units, the same as doors.
Switches in Doom follow the convention of having a name prefixed by SW1 (for the “Off” version) and SW2 (for the “On” version). However, this is purely a convention; the engine works with a hardcoded list of names, and a pair of custom textures named, for example, SW1DUMMY and SW2DUMMY will not be considered as a switch.
Switches follow a tiered system: all switches present in the shareware version of Doom are expected to be found in the full version; and all switches present in the registered version are expected to also be found in Doom II. However, since a few Doom switches were not used in the Doom II levels, they were replaced by dummies, despite the needed patches for their definition being actually present in DOOM2.WAD.
Animated switches are possible, if a switch texture (on, off, or both) is included in an animation range. This effect is notably used in Final Doom, where to achieve it the textures have not been sorted alphabetically.
|SW1BLUE||SW2BLUE||R||64×128||Skull in alcove on COMPBLUE wall|
|SW1BRCOM||SW2BRCOM||S||128×128||Fader with red/green LEDs on BROWN96 wall|
|SW1BRIK||SW2BRIK||C||64×128||Fader with red/green LEDs on BIGBRIK2 wall|
|SW1BRN1||SW2BRN1||S||64×128||Double-throw knife switch on BROWN1 wall — copy of SW#BRCOM in Doom II!|
|SW1BRN2||SW2BRN2||S||64×128||Green LED button on BROWN1 wall|
|SW1BRNGN||SW2BRNGN||S||128×128||Green LED button on BROWNGRN wall|
|SW1BROWN||SW2BROWN||S||128×128||Double-throw knife switch on BROWN96 wall|
|SW1CMT||SW2CMT||R||64×128||Double-throw knife switch on CEMENT3 wall|
|SW1COMM||SW2COMM||S||64×72||Fader with red/green LEDs on SHAWN wall|
|SW1COMP||SW2COMP||S||128×128||Button with red light on COMPTALL/COMPWERD wall|
|SW1DIRT||SW2DIRT||S||64×128||Fader with red/green LEDs on BROWN144 wall|
|SW1EXIT||SW2EXIT||S||32×72||Button with red light on GRAY5 wall|
|SW1GARG||SW2GARG||R||64×128||Embossed gargoyle face on METAL-like wall|
|SW1GRAY||SW2GRAY||S||64×128||Button with red light on GRAY1 wall|
|SW1GRAY1||SW2GRAY1||S||64×128||Green LED button on GRAY1 wall|
|SW1GSTON||SW2GSTON||R||64×128||Skull in alcove on GSTONE1 wall|
|SW1HOT||SW2HOT||R||64×128||Skull in alcove on SP_HOT1 (red bricks) wall|
|SW1LION||SW2LION||R||64×128||Embossed lion face on METAL-like wall|
|SW1MARB||SW2MARB||C||64×128||Skull in alcove on MARBLE1 wall|
|SW1MET2||SW2MET2||C||64×128||Fader with red/green LEDs on METAL2 wall|
|SW1METAL||SW2METAL||S||64×128||Green LED button on METAL1 wall|
|SW1MOD1||SW2MOD1||C||64×128||Green LED button on MODWALL1 wall|
|SW1PANEL||SW2PANEL||C||64×128||Skull in alcove on PANCASE2 wall|
|SW1PIPE||SW2PIPE||S||128×128||Double-throw knife switch on PIPE2 wall|
|SW1ROCK||SW2ROCK||C||64×128||Skull in alcove on ROCK1 wall|
|SW1SATYR||SW2SATYR||R||64×128||Embossed satyr face on METAL-like wall|
|SW1SKIN||SW2SKIN||R||64×128||Cacodemon eye on SKINBORD/SKINTEK wall|
|SW1SKULL||SW2SKULL||C||64×128||Double-throw knife switch embedded in giant skull computer on SP_FACE2 wall, to be bordered with SK_LEFT and SK_RIGHT walls|
|SW1SLAD||SW2SLAD||S||64×128||Red LED button on SLADWALL wall|
|SW1STARG||SW2STARG||S||128×128||Double-throw knife switch on STARG3 wall — copy of SW#BRCOM in Doom II!|
|SW1STON1||SW2STON1||S||64×128||Fader with red/green LEDs on STONE2 wall|
|SW1STON2||SW2STON2||S||64×128||Red LED button on STONE2 wall — copy of SW#BRCOM in Doom II!|
|SW1STON6||SW2STON6||C||64×128||Button with red light on STONE6 wall|
|SW1STONE||SW2STONE||S||64×128||Fader with red/green LEDs on STONE wall — copy of SW#BRCOM in Doom II!|
|SW1STRTN||SW2STRTN||S||64×128||Fader with red/green LEDs on STARTAN1 wall|
|SW1TEK||SW2TEK||C||64×128||Green LED button on TEKGREN2 wall|
|SW1VINE||SW2VINE||R||64×128||Green LED button on GRAYVINE wall|
|SW1WDMET||SW2WDMET||C||64×128||Blue (off) or red (on) skull on WOODMET1 wall|
|SW1WOOD||SW2WOOD||R||64×128||Skull in alcove on WOOD1 wall|
|SW1ZIM||SW2ZIM||C||64×128||Skull in alcove on ZIMMER1 wall|
The following codes are used in the “Version” column above:
- S - Shareware
- R - Registered/Ultimate Doom
- C - Commercial — Doom II
Heretic has only two types of switches, a "normal" one (SW1OFF/SW1ON) and an "exit" one (SW2OFF/SW2ON), with only one switch sound, called SWITCH. Although the switch textures are 64x128, they are usually used at a much smaller scale, indented in a little alcove, allowing to compensate for the lack of variety. The normal switch button shows a blueish-gray trident symbol, with the teeth pointing up and converging; while the exit switch shows a deep blue trident symbol, with the teeth pointing down and parallel.
Hexen offers more variety, with four different switch sounds depending on the switch texture. SWTCH6 serves as a generic switch sound, CHNSWCH8 serves as the sound for a chain being pulled, SWTCHRP1 for a rope being pulled, and SWTCHV4 for a valve handle being rotated. Finally, certain textures meant to be used with puzzle items have their own switch sound defined, PUZSLV. The switch animations are also improved, switch textures having not just an on and an off state, but also some intermediary steps. As an evolution of Heretic's design of placing switches in small alcoves, most of Hexen's switches are small textures, 32 in width and 32, 40, or 48 in height.