Earthquakes are a feature introduced to the Doom engine by Hexen. However, the implementation in ZDoom predates the release of Raven Software's source code, and as a result the earthquake code in ZDoom is completely different from its equivalent in Hexen.
Earthquakes can be created with the following three functions:
- A_Quake (an action function: can only be used in DECORATE)
- Radius_Quake (an action special: can be used anywhere)
- Radius_Quake2 (an ACS function: can only be used in ACS)
Earthquakes also play a continuous sound as long as they are rumbling. By default, this sound is the one defined in SNDINFO as "world/quake"; however both A_Quake and Radius_Quake2 allow to specify a different sound.