Difference between revisions of "Engine bug"
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[checked revision] | [checked revision] |
(Heretic has its own engine bugs page) |
(→Bugs present in Doom II version 1.9 for DOS: Add sectors with no geometry bug (as in Revolution! map05)) |
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! N | ! N | ||
|- | |- | ||
− | | [[ | + | | [[All-ghosts effect]] |
| Undisputed | | Undisputed | ||
| Overflow | | Overflow | ||
! N* | ! N* | ||
! N | ! N | ||
− | ! | + | ! Y |
|- | |- | ||
| [[Anomalous angry face behavior]] | | [[Anomalous angry face behavior]] | ||
Line 77: | Line 77: | ||
! N | ! N | ||
|- | |- | ||
− | | [[Arch- | + | | [[Arch-vile fire spawned at the wrong location]] |
| Undisputed | | Undisputed | ||
| Typo | | Typo | ||
Line 512: | Line 512: | ||
|- | |- | ||
| [[Moving platform heights not preserved in saved games]] | | [[Moving platform heights not preserved in saved games]] | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
| Undisputed | | Undisputed | ||
| Algorithm | | Algorithm | ||
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! N | ! N | ||
! N | ! N | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
|- | |- | ||
| [[PWAD size limit]] | | [[PWAD size limit]] | ||
Line 719: | Line 705: | ||
! N | ! N | ||
! S | ! S | ||
+ | ! N | ||
+ | |- | ||
+ | | [[Secret#Bugs|Secret sectors have no geometry]] | ||
+ | | | ||
+ | | Algorithm | ||
+ | ! N | ||
+ | ! Y | ||
! N | ! N | ||
|- | |- | ||
Line 763: | Line 756: | ||
! N | ! N | ||
|- | |- | ||
− | | [[Sleeping | + | | [[Sleeping shotgun guy in MAP02 (Doom II)]] |
| Undisputed | | Undisputed | ||
| Typo | | Typo | ||
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! | ! | ||
|- | |- | ||
− | | [[Slime | + | | [[Slime trail]]s |
| Undisputed | | Undisputed | ||
| Roundoff | | Roundoff | ||
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! N | ! N | ||
! N | ! N | ||
+ | |- | ||
+ | | [[Some Doom II-specific projectiles triggering linedefs]] | ||
+ | | Verified | ||
+ | | Algorithm | ||
+ | ! N | ||
+ | ! N | ||
+ | ! Y | ||
|- | |- | ||
| [[Some game options not preserved in saved games]] | | [[Some game options not preserved in saved games]] | ||
Line 805: | Line 805: | ||
! | ! | ||
|- | |- | ||
− | | [[Spawn | + | | [[Spawn cubes miss east and west targets]] |
| Undisputed | | Undisputed | ||
− | | | + | | Algorithm |
− | |||
! N | ! N | ||
+ | ! Y | ||
! N | ! N | ||
|- | |- | ||
− | | [[Spawn | + | | [[Spawn fog in wrong location]] |
| Undisputed | | Undisputed | ||
− | | | + | | Typo |
+ | ! N | ||
! N | ! N | ||
− | |||
! N | ! N | ||
|- | |- | ||
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! Y | ! Y | ||
|- | |- | ||
− | | [[Tag 666# | + | | [[Tag 666#Difference in behaviour between Doom1 and Ultimate Doom|Tag 666 idiosyncrasies]] |
| Undisputed | | Undisputed | ||
| Algorithm | | Algorithm | ||
Line 908: | Line 908: | ||
! N | ! N | ||
! N | ! N | ||
+ | ! Y | ||
+ | |- | ||
+ | | [[Things snap up to ledges when sectors move]] | ||
+ | | Undisputed | ||
+ | | Algorithm | ||
+ | ! N | ||
+ | ! Y | ||
! Y | ! Y | ||
|- | |- | ||
Line 941: | Line 948: | ||
| Undisputed | | Undisputed | ||
| Static limit | | Static limit | ||
+ | ! N | ||
+ | ! N | ||
+ | ! N | ||
+ | |- | ||
+ | | [[Vertical offsets are ignored in texture patches]] | ||
+ | | Undisputed | ||
+ | | Algorithm | ||
! N | ! N | ||
! N | ! N |
Latest revision as of 18:19, 12 April 2024
A Doom engine bug is a limitation or an oddity present in the Doom engine. For errors in map design, even those related to a specific item below, see the article about that map.
This article uses the version 1.9 DOOM2.EXE DOS version as the base version. Older versions, the source release, Final Doom and The Ultimate Doom have some minor changes, tweaks and different bugs.
Note that playing with a source port may, while removing some or even the majority of the bugs listed below, introduce other bugs which are not listed here (although details may be present in the article about the source port in question).
Contents
Key[edit]
This table classifies anomalies in a very broad way; see the individual articles for details.
- Canonicity — A bug is verified only when a current or former id Software programmer has called it a bug in a public medium. An unverified bug may still be undisputed if it is generally accepted as an error or issue by the fan community under a consensus involving thorough playtesting and research on the corresponding phenomenon and any associated binaries or source code. A bug is disputed if it can be argued to be a harmless and possibly intentional feature.
- Cause — The general category of underlying problem:
- Most bugs are due to algorithms which fail to account for all possible inputs, apply conditional statements in an illogical sequence, or have unforeseen consequences in particular game situations.
- A few of these arise from simple typos in the source code.
- Improperly constructed linedefs (with orphaned tags or incorrectly placed textures) or sectors, can also induce various strange behaviors.
- The Doom engine includes few safeguards against overflow conditions.
- Line-of-sight calculations, rendering algorithms, and the BSP tree are also susceptible to roundoff errors.
- The engine imposes a number of static limits on Thing placement and map construction, which sometimes fix one problem by creating another.
- Most bugs are due to algorithms which fail to account for all possible inputs, apply conditional statements in an illogical sequence, or have unforeseen consequences in particular game situations.
- Fatal bugs are those where the engine crashes (often with the Venetian blind effect) or else exits the game in a controlled fashion, usually with an error message. Y* means that termination is possible, but not inevitable. N* means that the program keeps running, but that rendering or character behavior may be sufficiently compromised that meaningful gameplay becomes impossible.
- A bug has a workaround if it can be avoided by reasonable compromises in map design, such as when matching every linedef tag to at least one sector, but not when removing invulnerabilities from every level containing a sky texture, or also by convenient precautions and other measures taken by the program user, such as when increasing the mouse sensitivity through the configuration file directly, instead of using the menu. S means that the bug can be avoided only by making one's map smaller or less complex.
- A bug is a loophole if it can be abused to the player's advantage (especially during speedruns or deathmatches).