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Why This Rare Bug Turns Everything into Unkillable Ghosts
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- Published on May 30, 2023 veröffentlicht
- Exploring the elusive all-ghosts bug. Spooky!
MAP21 all-ghosts footage by A1s:
• Me Getting the Al...
Music used in order:
"Another World of Beasts" from Final Fantasy Anthology
"Journal" from Flashback (MIDIfied by Simon Agozzino)
"Mist" by Stuart Rynn
"Derelict" by Ivan Stanton
"The Doom World Is Flat" by decino
Patreon:
www.patreon.com/decino 
Gaming
Never encountered this one in all my years of playing Doom. This is awesome, now I have to try and make it happen for giggles.
Keep in mind this only happens in Doom ports that:
1) Share similar memory addresses;
2) Don't fix ray cast rounding errors;
3) Don't fix the intercepts array overflowing.
PrBoom+ for example can only emulate the all-ghosts effect behaviour, but it doesn't actually directly overwrite memory through the intercepts array.
omg it's the funny madness man
Doom madness animation? 👀
Video was released 4 minutes ago, this comment is 20 hours ago, mmmkay
hmmm i see lol
Coming back after Zero Master used the insights from this video to get new world records in E1M8 and Plutonia map 11. Congratulations, decino! You deserve a Nobel prize in Doom science.
Very cool this video inspired a new speed run tactic
9:20 so how does Zero Master do it reliably enough to use?
OK I see his explanation in the description of his video. Basically his brute force method was using inputs that he could replicate without TAS. Still I wonder how precise do the inputs have to be?
His video:
clip-share.net/video/P01d-AmqByU/video.html
@YogiTheBearMan Karl Jobst has covered Zero Master's technique here:
clip-share.net/video/T_5ZYJBgQyM/video.html
He explains that Zero Master's simulations performed about 300 years of gameplay to find the solution. Great video.
I love how on the surface, Doom is "shoot it until it dies" but underneath there's a bunch of quirks like this. And then you have ASMR doom pumpkin man explaining it to you. Better than uni
my favorite fact about this bug is that chocolate doom has a different memory layout (so it wouldn't work the same way), so instead, chocolate doom *manually* recreates the effect by overwriting the appropriate variables in the same order
Same with Prboom+.
"The only way to exit the level is through a death exit damaging floor."
Dude, that is obscure as hell. You're amazing at analyzing the Doom engine and pushing it to its limits. I don't think anyone has ever gone this far and this deep. I always get happy when you release a new video like this.
Well i mean doom's ray tracing only takes into account anything on the x or y axis since those are the only two axes you can aim and shoot on that have anything to intercept your bullets with so it's kind of obvious why pools and damaging floors can still hurt doomguy,
Still obscure as hell. Everything in this video is.
Glad Karl pointed me towards this video and your channel. Super cool videos! Just insane that your video about this glitch, and your breakdown was eventually used to actually find a practical use for this bug, and used to break another Doom speed run! Leave it to you crazy talented maniacs to find out how this all works, and how to exploit and activate these glitches, even if it takes years to do so!
Congrats to you all!
It's all fun and games until the demons decide to use idclip
Doomguy: Uses cheat codes
Demons: Understandable have a nice day
Demons: Uses cheat codes
Doomguy: Wait, that's illegal
This is 1 bug I always encounter: in the MS-DOS Doom1 E1M6 in the maze-like part, there's a zombieman who somehow appears outside te walls, forever haunting nobody. If that happens, you can't reach 100% kills without idspispopd.
Doomguy: Wait, this is Doom 2, so why is BFG Division playi-
Demon: *use idclip*
Doomguy: "You dare use my own spell against me, demon!"
and It's all fun and games till the demons decide to use iddqd
The scariest thing here aren’t the ghosts, not able to complete levels, or even this ruining a speed run.
It was the code.
looks like you guys getting so close getting those last secrets in e4-3 and icon of sin pacifist! maybe one day...
This was a missed opportunity to call this video “whoops, all ghost”
As soon as I heard him call it the "all ghosts bug" I thought the same joke. :D
Good!
Seeing Karl recommending decino put a smile on my face and warmed my heart!
It's like this is a glimpse of the true form of noclip, where not even projectiles can interact with you... I love how much effort you put into these obscure quirks and trivia from a game that seemingly has risen in popularity once more after decades of being extremely niched. Thank you ducino, and cheers!
Funnily enough, before there was research done into why this bug happens, it was known to deathmatch players as something along the lines of "the DM noclip bug", because if there's no monsters around it just looks like everyone turned on noclip at the same time.
Ducino
@Space Detective But even that is kind of a misnomer, because noclip doesn't prevent you from flipping switches and it doesn't stop your projectiles from colliding too.
Caco-Boo is a blessed creature I didn't know I needed in my life.
Same, it looks so cute!
Feels like a Golden Souls enemy
Is it rule 34 immune?
@Raul Salcedo dont give them ideas
@Raul Salcedo The only thing that is given an exception to Rule 34 is if its a citation of Rule 34 also called Rule 35.
Otherwise no because it is something that is concieved making it exist so it is under Rule 34. (Unfortunately...)
Hello you absolute Legends. ZeroMaster shows us why he's the greatest speedrunner in Doom history yet again.
I encountered this bug once as a kid. I don't remember which map it was but I remember never wanting to play that map again because of how creepy it was. It makes me wonder what kind of interesting things you can do with this bug that haven't been discovered yet
Here from Karl, but it's not my first time. I've seen these videos so many times by now, Karl just gave me another reason to watch them again.
Ive been paying doom for over 15 years, never in my live heard of this, marvelous how Decino never stops surprising me with new things every video. Amazing
My man finally got the recognition he deserves
I love that, despite Doom being a game older than a significant part of Clip-Share's overall userbase, you've still managed to build an entire channel primarily on the game's myriad quirks.
Also, at 10:01, is that Mr. Bones' Wild Ride on the right? Nice subtle nod to another legendary old game.
The series is still getting new releases, and I think they even put at least one of the old ones in Eternal; there's the Unity port for everyone on console as well, and it's dirt-cheap (5 bucks for each game, and it goes on sale sometimes), and it's shaped up to be a very respectable source port (as opposed to the disaster it launched as) and even include a bunch of prominent WADs as well. Doom is arguably more accessible now than it's been since its heyday, even the most tech-illiterate person can just buy it, download and play.
@Hooded Man Yep! When I heard doom eternal was coming out, I bought doom 2016, and after that decided to play through doom 1 and 2 before it released. I had _heard_ of doom before, but had never sat down and played it. I'm now a big doom fan even working on a custom 7 map wad, and after that's done I'm going to give final doom a go.
@KingKuma 411 Nice! That's quite the dedicated fan you've become! Is there a place I can follow your progress on your wad, perhaps? Maybe reply to this comment chain when it's done?
@E5rael Yeah, I can do it.
Lol, it does actually look like it IS Mr. Bones' Wild Ride, superimposed on a revenant.
"Hmmm, decino hasn't posted a video in a while, I hope he's ok."
"Y'know, he's probably fine, just working on a yellow video"
-me for the last 2 weeks
Good to see you're still with us and not a spooky ghost lol
....I guess you just got a deci-boo
@John Dexter Zarate he posted on a community team that he was out of town and busy on a new video some time before this video
As a fledgling programmer, learning about dooms code is so educational and entertaining
Decino hearting comments a year later. What a legend. P.S. His Serious Sam videos are goated, specifically the 100% playthroughs.
Learned something new today. These series on how the doom code work are really interesting. I'd love to see some breakdowns for more contemporary engines.
This leads to the very mysterious question: "Who asked?" Well, to understand the question, we have to understand the answer: So this very particular question is asking about who asked, the question is divided into two parts: Who & asked "Who" is what is called an "Interrogative word" which specifies the answer to make it suitable for the question, the "Who" here is specifying a person/human/homo sapiens/guy which has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. Second: "asked" is a verb in the second condition of the forms of the verb, which are divided into three types: Regular, Past, or Past participle. and the verb "asked" is in the "Past" condition, which talks about the time that is gone and no longer exists. The original form of this particular verb is "ask", which is to say something in order to obtain an answer or some information. So, to summon what the answer wants from the previous two points, it's that: The answer wants to understand and know about the person/human/homo sapiens/guy who wanted to say something in order to obtain an answer or some information. So, in order to answer this question, we will have to identify two points: First: What was the question that the subject of the answer to the question "Who asked?" asked? Well, to understand this question, we will NOT have to understand what is the answer. We will just have to understand the definition of "Question" The "Question" is A sentence worded or expressed so as to elicit information. Questions could be identified using the "Interrogative Words", which we talked about earlier. these "Interrogative Words" are nine, which are: Who, What, Where, Why, Which, When, Whose, Whom, and How. We are going to explain each individually: As we said earlier: "Who" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. "What" is specifying a non-person/non-human/non-homo sapiens/non-guy who either does not have a brain that he can understand and think properly with, like plants, or objects, or they have a brain, either that their brains cannot understand and think properly, like animals, or their brain can understand and think properly, but their species/type is rather different from the society, like extraterrestrial creatures, so the answer should be as I said in the abstract: A(n) animal, plant, extraterrestrial creature, or object. "Where" is specifying a place, city, country, continent, etc. where something happens, or some(one/person/human/homo sapiens/guy), plant, animal, extraterrestrial creature or object which exists in a place, city, country, continent, etc. "Why" is specifying a reason for doing something. "Which" is specifying a choice of either two or more choices that the receiver of the question usually chooses. "When" is specifying a time in which either something already happened, or something will happen in either near, or far future, for example: "When will anyone save me as I was captured by MatPat for trying to comment a joke about his video?" "Whose" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, and that person/human/homo sapiens/guy owns something, or someone ( if he is a human trafficker ), and the sender of the question is trying to find who owns that something, or someone. "Whom" is an old-fashioned term, not often used today. Many native English speakers are less than clear about its accurate use. In fact, the word serves the same purpose as "Who" questions, which as we said: specifies a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human, but tends to be used when it is the object of the verb. With modern English, there is no real need to use the term. "How" could be referring to the way something is done or refers to the status of the receiver of the question. Now, let's get back to where we were talking: Questions can be different, and many, and the possibility of guessing the question could be high or low according to the frequency of using it, but guessing a question which was asked for the first time is very difficult, so, it is not specific what was the question that the subject of the answer to the question "Who asked?" asked. Second: What is the purpose of the question "Who asked?"? Well, it could be referring to roasting someone as the humor of "No one asked.", and it could be referring to actually asking a question about who asked the question. So, here's the answer to the question "Who asked?": It could be anyone who made something unlikely for the others or someone who asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else. (s)He could be you. (s)He could be me. (s)He could be Elon Musk. (s)He could be even your mom. as long as they have made something unlikely for the others or they have asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else.
I actually encountered this for the first time quite recently... just a few months ago while playing through TNT Evilutuion in Map 09: Stronghold. At the time I had no idea what it was, and assumed I'd triggered the void glitch somehow by accident (i.e. the one speedrunners use in Doom 1's Halls of the Damned to get to the exit). But now that I've seen this, and given the large enemy count for that map (at least by 1996 commercial Doom IWAD standards), now it makes sense how I triggered this bug. If anyone wants to mess around with that map... I think(?) I was in the southwest portion of the map, but like I said, it's been a few months now, so I could be remembering wrong.
You forgot to mention that TeamTNT was well aware of this bug. They made it easier in TNT: Evilution by spawning all 147 hitscanners at once, making the ghost state more reasonable to achieve.
I think I accidentally encountered this bug as a kid, and it was entirely 2spooky. I used to play the Icon of Sin level with cheats on for hours, just shooting tons and tons of demons. I think one day I lost the ability to shoot them, and it was scary. Just like the day I discovered you can be telefragged even while "invincible"
I wish my teachers would explain complicated stuff like you do. I never played or watched anything doom related until one of your analysis videos got recommended to me. Even tho I never watched or played doom your videos are very entertaining. Keep it up!
decino: your position and angle need to be absolutely dead on
Zero Master: challenge accepted
Huge thanks for this informative video! I feel like it might not get as many views as your other analysis videos, but boy, was it a real treat to watch. Looking forward to more coverage of obscure bugs!
Always good to see another video from you decino. Also grats on 130k, I'm looking forward to whenever the next Sunder stream will be as you got some amazing levels coming up.
Also I recommend anyone who enjoys decino's doom wad playthroughs, especially the difficult ones, to subscribe to A1s(the link in this video description) as his content is fairly similar.
I have never seen this awesome rare bug while ever playing this game. The block map bug however...
The block map bug is pain
Chainsawing a mancubus. Enough said
I hate that it exists in Eternity and cannot be turned off in the compatibility options. Forgive me skillsaw, but I ain't completing Heartland until that happens.
I haven't seen this since playing Doom on a 0486 years ago.*
*On regular vanilla maps.
Those visualizations probably took a very long time to make, on top of all of the research and writing. Amazing content.
Loving the ghostly imagery. The ride never ends with decino
I love seeing the influx of people to your channel Pumpkin Man, you are a true absolute legend!
Despite how annoying it would be, This would be a pretty cool mechanic for a map where waves of demons just appear out of the walls in a giant arena! It would add a sense of; "oh I wonder what the next enemies going to be!" (being able to shoot them of course) I want to see someone make this and get decino to play it!
I love how Classic Doom is in still technically marvelous and fascinating, despite being archaic.
Makes you respect how much work goes into making games.
Think of all that goes on (sometimes) seamlessly in modern games.
And look at Doom now!
The amount of sheer calculations and potential interactions boggles the mind.
I remember seeing this exact bug in one of Altimamantoid's outtakes with TNT Map 22 ten years ago. It happened right in the middle of his rant about awful the map was and it killed him within seconds.
Clearly the map didn't like being badmouthed and got revenge.
Well that and it was a community map that was never meant to be bought so having TNT Evilution's quality go south in the middle towards the end of the megawad would have been fine if it was released for free like it was planned to. Honestly i would have been fine with just the plutonia experiment as final doom.
@Micheal Persicko For the most part, I enjoyed TNT Evilution. Most of the levels are creative and interesting, and pushed the engine in various directions. Also, it's not like the original doom2.wad was the greatest thing either. No one had yet truely mastered the art of Doom map making, the tools at the time were poor, and computers couldn't handle anything beyond simple map geometry with only a handful of enemies onscreen at a time.
Now, I personally dislike Plutonia. It seems to love putting hitscan enemies and archviles in places that are very awkward to aim into or hidden, so that you take a bunch of unavoidable damage if you don't have the proper approaches memorized, and has too many combat arenas where movement is downright awkward. Also, the architecture is, with a few exceptions, rather bland and repetative. Where in TNT you never know what sights you'll see around the next corner, with Plutonia it will surely be more brown walls with green vines and chaingunners.
I've played through all of TNT twice. With Plutonia, I started two or three times, but never got past the second or third level before getting bored and annoyed and dropping it.
@Micheal Persicko Plutonia and Evilution are a perfect pair -- for people like me who hate Plutonia's high-difficulty, short-length maps and prefer to actually spend time exploring without running like a blue-assed fly from revenant missiles. Either one alone would leave a chunk of players disappointed.
Been playing doom for 20+ years and I've never seen this bug once, what a great explanation of something so cool and rare. Thank you!
This leads to the very mysterious question: "Who asked?" Well, to understand the question, we have to understand the answer: So this very particular question is asking about who asked, the question is divided into two parts: Who & asked "Who" is what is called an "Interrogative word" which specifies the answer to make it suitable for the question, the "Who" here is specifying a person/human/homo sapiens/guy which has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. Second: "asked" is a verb in the second condition of the forms of the verb, which are divided into three types: Regular, Past, or Past participle. and the verb "asked" is in the "Past" condition, which talks about the time that is gone and no longer exists. The original form of this particular verb is "ask", which is to say something in order to obtain an answer or some information. So, to summon what the answer wants from the previous two points, it's that: The answer wants to understand and know about the person/human/homo sapiens/guy who wanted to say something in order to obtain an answer or some information. So, in order to answer this question, we will have to identify two points: First: What was the question that the subject of the answer to the question "Who asked?" asked? Well, to understand this question, we will NOT have to understand what is the answer. We will just have to understand the definition of "Question" The "Question" is A sentence worded or expressed so as to elicit information. Questions could be identified using the "Interrogative Words", which we talked about earlier. these "Interrogative Words" are nine, which are: Who, What, Where, Why, Which, When, Whose, Whom, and How. We are going to explain each individually: As we said earlier: "Who" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. "What" is specifying a non-person/non-human/non-homo sapiens/non-guy who either does not have a brain that he can understand and think properly with, like plants, or objects, or they have a brain, either that their brains cannot understand and think properly, like animals, or their brain can understand and think properly, but their species/type is rather different from the society, like extraterrestrial creatures, so the answer should be as I said in the abstract: A(n) animal, plant, extraterrestrial creature, or object. "Where" is specifying a place, city, country, continent, etc. where something happens, or some(one/person/human/homo sapiens/guy), plant, animal, extraterrestrial creature or object which exists in a place, city, country, continent, etc. "Why" is specifying a reason for doing something. "Which" is specifying a choice of either two or more choices that the receiver of the question usually chooses. "When" is specifying a time in which either something already happened, or something will happen in either near, or far future, for example: "When will anyone save me as I was captured by MatPat for trying to comment a joke about his video?" "Whose" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, and that person/human/homo sapiens/guy owns something, or someone ( if he is a human trafficker ), and the sender of the question is trying to find who owns that something, or someone. "Whom" is an old-fashioned term, not often used today. Many native English speakers are less than clear about its accurate use. In fact, the word serves the same purpose as "Who" questions, which as we said: specifies a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human, but tends to be used when it is the object of the verb. With modern English, there is no real need to use the term. "How" could be referring to the way something is done or refers to the status of the receiver of the question. Now, let's get back to where we were talking: Questions can be different, and many, and the possibility of guessing the question could be high or low according to the frequency of using it, but guessing a question which was asked for the first time is very difficult, so, it is not specific what was the question that the subject of the answer to the question "Who asked?" asked. Second: What is the purpose of the question "Who asked?"? Well, it could be referring to roasting someone as the humor of "No one asked.", and it could be referring to actually asking a question about who asked the question. So, here's the answer to the question "Who asked?": It could be anyone who made something unlikely for the others or someone who asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else. (s)He could be you. (s)He could be me. (s)He could be Elon Musk. (s)He could be even your mom. as long as they have made something unlikely for the others or they have asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else.
Apparently this glitch also happens when trying to load a massive map, but it happens differently depending on the source port. GZDoom does turn enemies into ghosts, but vanilla compatible ports make the monsters solid but invincible.
Really weird
Is it just me, or is anyone else super impressed for how intricate Dooms programming was for its time?
This leads to the very mysterious question: "Who asked?" Well, to understand the question, we have to understand the answer: So this very particular question is asking about who asked, the question is divided into two parts: Who & asked "Who" is what is called an "Interrogative word" which specifies the answer to make it suitable for the question, the "Who" here is specifying a person/human/homo sapiens/guy which has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. Second: "asked" is a verb in the second condition of the forms of the verb, which are divided into three types: Regular, Past, or Past participle. and the verb "asked" is in the "Past" condition, which talks about the time that is gone and no longer exists. The original form of this particular verb is "ask", which is to say something in order to obtain an answer or some information. So, to summon what the answer wants from the previous two points, it's that: The answer wants to understand and know about the person/human/homo sapiens/guy who wanted to say something in order to obtain an answer or some information. So, in order to answer this question, we will have to identify two points: First: What was the question that the subject of the answer to the question "Who asked?" asked? Well, to understand this question, we will NOT have to understand what is the answer. We will just have to understand the definition of "Question" The "Question" is A sentence worded or expressed so as to elicit information. Questions could be identified using the "Interrogative Words", which we talked about earlier. these "Interrogative Words" are nine, which are: Who, What, Where, Why, Which, When, Whose, Whom, and How. We are going to explain each individually: As we said earlier: "Who" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. "What" is specifying a non-person/non-human/non-homo sapiens/non-guy who either does not have a brain that he can understand and think properly with, like plants, or objects, or they have a brain, either that their brains cannot understand and think properly, like animals, or their brain can understand and think properly, but their species/type is rather different from the society, like extraterrestrial creatures, so the answer should be as I said in the abstract: A(n) animal, plant, extraterrestrial creature, or object. "Where" is specifying a place, city, country, continent, etc. where something happens, or some(one/person/human/homo sapiens/guy), plant, animal, extraterrestrial creature or object which exists in a place, city, country, continent, etc. "Why" is specifying a reason for doing something. "Which" is specifying a choice of either two or more choices that the receiver of the question usually chooses. "When" is specifying a time in which either something already happened, or something will happen in either near, or far future, for example: "When will anyone save me as I was captured by MatPat for trying to comment a joke about his video?" "Whose" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, and that person/human/homo sapiens/guy owns something, or someone ( if he is a human trafficker ), and the sender of the question is trying to find who owns that something, or someone. "Whom" is an old-fashioned term, not often used today. Many native English speakers are less than clear about its accurate use. In fact, the word serves the same purpose as "Who" questions, which as we said: specifies a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human, but tends to be used when it is the object of the verb. With modern English, there is no real need to use the term. "How" could be referring to the way something is done or refers to the status of the receiver of the question. Now, let's get back to where we were talking: Questions can be different, and many, and the possibility of guessing the question could be high or low according to the frequency of using it, but guessing a question which was asked for the first time is very difficult, so, it is not specific what was the question that the subject of the answer to the question "Who asked?" asked. Second: What is the purpose of the question "Who asked?"? Well, it could be referring to roasting someone as the humor of "No one asked.", and it could be referring to actually asking a question about who asked the question. So, here's the answer to the question "Who asked?": It could be anyone who made something unlikely for the others or someone who asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else. (s)He could be you. (s)He could be me. (s)He could be Elon Musk. (s)He could be even your mom. as long as they have made something unlikely for the others or they have asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else.
i played Doom as a kid a lot and out of pure nostalgia installed it on my new pc 3 years back and encountered it in e2m1 never knew how wildy rare it was
Decino, I was furloughed for basically all of 2020 and I found your channel at the beginning of quarantine right after I beat DOOM, 2, 64, and 2016. I love watching all your videos and your play series, especially when you tried DOOM 64. I started working a new job in February and I have missed so many videos unfortunately. I just opened Clip-Share and I saw the yellow background for this video and got so excited; I felt like I was pulled back to 2020 for a second in a good way. I just wanted to get weirdly sentimental and say thank you for keeping me sane through that crazy year :)
6:37 That is one horrifiying image. The endless maw of hell's demons just trying to shake their way through matter... It's so unsettling.
Oh you want to know what i see
Hehe cocademons squeeze line
0:16 seems much more frightening, due to the fact that nothing is stopping them, and there's eerie music playing.
@Lugbzurg Playing Another World of Beasts/Esper World was a good choice.
imagine how awkward it would be if doomguy and the demons realized they can't hurt each other
I've ran into this a couple of times, and never knew why all the Archies were suddenly coming through the walls to blast me to kingdom come. Now I do. :)
It's kind of staggering that path checking continues to be calculated even when a shot is "stopped" by a solid object; this really seems like a rookie oversight at the initial coding stage.
I'm also intrigued by overflows in general; they seem like something that simply shouldn't happen, trying to add something to a full array should just drop the extra data (consequences of missing data ending up in the Too Bad Basket), not freely overwrite beyond its allocation; otherwise what's even the point of declaring a length?
Not even using bounds-checking is very elementary, despite the ingenuity of a lot of Carmack's code in Doom like his use of BSP trees.
I'm not an expert on overflows but I do know that earlier versions of C contained many functions that weren't memory-safe, for example using 'gets' instead of 'fgets', or 'strcpy' instead of 'strncpy'. I know they wrote this code in Objective-C which I have no experience in but perhaps there are similar functions there as well.
Just yesterday I was talking to a friend about ghosts, but felt almost silly I didn't have the explanations. "Man, I wish Decino could tell me..."
Then, Decino comes through. With the greatest knowledge. Thank you, seriously. You're the best.
As somebody who was deeply familiar with the Doom engine and Bungie's Marathon engine (even moreso, I made full conversions), I've never seen this bug. Super interesting shit, I love your channel man, 2.5d shooters are just such interesting pieces of history. Once I learned that I was basically a triangle bumping around a bunch of 2d polygons, my whole world was flipped upside down.
Videos like this are exactly why I like your channel. Deep, deep dives into the nooks and crannies of Doom's code... I wish more channels did stuff like this. I know there's that one guy who does Paper Mario videos like this, but beyond you two, I can't think of anyone else.
It had a really missed opportunity to be called “the specter bug”
Cause thats a ghostly named enemy
Nothing to do with partial invisibility tho.
i think when it was named, specters didn't exist in doom so i don't think it was an idea to come up with
@Luuestenfaus so it was named before the game came out
@Luuestenfaus No idea why this comment has any likes, that's so untrue. Spectres have always existed in Doom. No idea where you got the idea that this insanely rare bug that likely wasn't discovered until some time after Doom II or even Final Doom released -- would be named as a "ghost" bug because spectres didn't exist... It's because you literally act like a ghost. You can go through walls and are barely able to have any interactions at all.
Spectres can interact with the environment... and attack.. and be hit. So what way is this remotely similar to how Spectres function....?
The weird bullshit some of you guys say is insane.
whoa, look, i was just misunderstood, i thought he was talking about the spirits from doom eternal :\ now, instead of starting an insanely dumb argument, i misunderstood the enemy and i apologize!
thanks decino, as a software engineer its awesome hearing the detailed explanation of these bugs, nothing like a good old array index out of bounds / overflow
By far the best analysis you have ever done. You solved a really weird, long running mystery.
When I was a kid I used to accidentally trigger this bug on Plutonia's MAP30 by waking up the Icon, turning on god mode, and then seeing if I could fill up the entire map with monster bodies. After a while of doing this they started noclipping and I couldn't kill them. I always just assumed I overloaded the game with too many enemies.
Yeah, I ran into this bug the same way back in the day (though in my case it was on Doom 2's MAP30). As much as I like understanding how and why it happens, it still takes some of the magic out of it. :P
Man, that bit at 06:40 where all the monsters are mashed up against that one tiny window staring at Doomguy is legit creepy lol
This is by far the most obscure topic in your DooM video analysis... i had to watch it twice to understand it.
Its great to have you back decino. Hope your renovations are now fully complete and you're back and confortable at home :)
I remember having nightmares as a kid like this, being stuck in Doom but the monsters were unkillable.
Did they also chase you out of bounds when you tried to use noclip or freeze?
s p o k i
I've never seen the all ghost glitch happen before, but I do remember watching my dad play this as a kid and him getting the archvile ressurrection ghost glitch occasionally. I specifically remember it only ever being ghost chaingunners though, nothing else. We always just assumed it was a glitch specific to chaingunners. Kinda odd. 🤔
The method of only checking cubes via block maps is genius! I'm working on my own game, and collision testing is quite costly, so I'm going to implement it! Thank you!
Obviously, I'll improve it haha
I've only encountered this bug one time. On that one Plutonia map with all the shotgun guys and archviles (I think it was MAP14 or 15), one of the archies resurrected a shotgunner that got squished by a door while dying, it scared the crap out of me when I came back to that room only to have a shotgun guy just casually walk through the wall and riddle me with buckshot.
Actually, upon unpausing the video, this is actually about a different ghost bug LOL.
The fact that there's a way to trigger the candle secrets in Sever the Wicked is so cool
Once again decino provides great analysis of rare and unique phenomena of the Doom code.
"Deep into the code" would have been perfect for this. Excellent work and explanation !
Knee Deep In The Code
@mjc0961
The Shores of Code
In-Code
Thy Code Consumed
Sign(Sigil)
And finally:
*Tech Gone Bad*
@mjc0961 Yep, there we go. That's brilliant. ♥
Codemonium
The ancient code
For such an old game, I think this is the second most technical video ever; the first one being an explanation of multiple/parallel universes in Super Mario 64.
Anyway if you are curious about these odd behaviours, I might have extra material for you to investigate on :D
I've always wondered about this one. I feel like a huge mystery has finally been solved. Great work! I'd love to see you cover more Doom bugs!
The Legends are coming!
As a programmer, if you're short on bugs just ask people to implement any kind of geometry routine
This one was great and super interesting! The idea you can overflow pieces of the memory with too many objects in the path of a shot.......surely someone has to put that to use in a map somehow? You could give it a teleporter exit so it's still completable. 🤔
I've played the classic doom games since they came out. Never have I managed to see this bug happen. This is why I enjoy this channel, it shows how much there still is to find in old Doom
Encountered this on MAP30 of the v1.666 release of Doom II in the late 90s, I think once. Never understood how it happened at the time, but I distinctly remember somehow passing out of bounds and seeing hundreds of demons out of bounds with me. As a kid I just assumed that’s how the Icon spawned them, by teleporting them into bounds from the out of bounds area. All along, I probably just inadvertently triggered this bug.
With this amount of code researching so far, I wonder if decino is going to make a source port of his own in the future.
Fun story about level design: I was making my first level and making a secret door. Unfortunately I used the wrong Doom Builder tag and caused rampant lighting glitches and the ceiling to infinitely rise after trying to open the secret door. I still have a video of it on my phone.
Oh man!
I accidentally triggered this exact bug years ago, in the Icon of Sin level, and had no idea how it happened, until now!
Thank you for making this video!
I really appreciate how deep you're going into the code and how you can explain it so easily...
You're like David Attenborough of DooM
Glad you’re back, this was probably one of the most interesting analysis videos
This definitely is the most bizarre bug in the original DOOM games. I've start DOOM in the late 90s and to this day, I've never had this bug happen to me with every one of my playthroughs.
Can I just say the sunlust music is fantastic for background ambience? I did not expect this subject from that thumbnail preview, the caco boo is adorable. Also this is probably your best thumbnail from the doom analysis videos in my opinion, very well made.
I think I remember this happening to me back in the day. I was confused as to why it happened and I could not kill anything. I was 12 so I can't be entirely sure this was it, but this was before I discovered cheat codes that allowed me to clip through walls.
Thank you so much for making this analysis video, decino! I had mentioned to you previously that I was pretty familiar with the intercepts overflow, but I still didn't know all the specifics regarding things like how many intercepts were needed to cause the all-ghosts effect. I've encountered the overflow dozens of times in the past few months (not including intentionally triggering it) and I've seen it cause different issues at times. Perhaps the following info will be useful to you and also explain what happens when too many intercepts occur (some people were asking about that in the comments and I have the answer :D).
On one of my own maps, the overflow was very easy to trigger (too many linedefs for extra lighting variation). However, it seemed to be incredibly minor and I was unable to notice any issues with gameplay. The only reason I knew it occurred was thanks to PrBoom+'s optional warning message (very handy for playtests!). The player starts could get messed up in cooperative if a few player corpses were lined up with the ceiling lights. I fixed this as soon as I discovered it on that map by reducing the amount of lighting variation slightly :D
The epic slaughtermap, Heck on Earth (the one I mentioned with the ghost funnies :D), from my upcoming megawad does have a small chance for the all-ghosts effect. It's situational as it'll require a lot of monster corpses to be lined up, but with 1,080 monsters that's definitely not too difficult. The map gives the monsters plenty of room to move around so this should be very rare and I have tweaked it to help reduce the chance (I also playtest my maps 100+ times for quality assurance :D). Before tweaking it, I encountered the overflow again, but this time it seemed to make collision less precise, although the map was still playable. I mean, 7 SSG shots to kill an Arachnotron when you're right up in his face is definitely not just bad RNG and the blockmap bug :D
The intercepts overflow is guaranteed to crash vanilla DOOM if there are too many additional intercepts. As far as I know, PrBoom+ will never crash from this overflow, although I have seen it crash due to the playeringame overflow once. That interceptsoverflow.wad you demonstrated at the beginning easily crashes vanilla due to how many things and linedefs are placed in a row. I'm not sure what the exact minimum number is, but it eventually gets to a point where the game will immediately crash and leave an error message at the DOS prompt (or the game will freeze and you'll have to reboot DOS or close DOSBox :D). I've personally seen two messages with the first one being the most frequent ("P_CrossSubsector: ss %i with numss = %i" and "R_Subsector: ss %i with numss = %i"). Doomwiki states that these errors should never occur, but the error message article does note that various overflows may trigger messages like these.
Sometimes, DOOM may completely freeze and DOSBox will crash occasionally. I haven't run any intentional intercepts overflow tests on any of my DOS machines yet, but I do plan to in the near future as DOSBox can be both more stable and less stable than a real DOS environment depending on the situation. I've experienced crashes that have happened sometime after the all-ghosts effect is triggered, but usually the game seems to die instantly if a crash is going to happen.
I witnessed something very peculiar today while experimenting with the bug in vanilla using -solo-net (AKA using ipxsetup.exe and -nodes 1 instead of the modern source port parameter). I was adding additional corpses to a room by blowing myself up multiple times and after one of these deaths, I instantly blew up a second time when I respawned! The overflow had already been triggered at this point, but the player starts were still functional. I have no idea what happened, but I'll keep trying to replicate this and get a demo recording for someone to analyze (perhaps you'd like to check it out? :O)
Anyway, I hope this information based on my own experience and experimentation is useful! I greatly appreciate this video and you were able to answer some questions I still had about this crazy bug. The main thing that confused me was demos with intercepts overflows that were seemingly triggered by far less intercepts than 128, so I'm really glad that mystery was solved! I assume that's why the overflow can happen on Black Tower and why I was unable to replicate it (I'll keep trying, though :D). Thanks again for this excellent addition to the analysis series and congratulations on 130k subscribers!
P.S. I like the funny Pain Elementals at 6:46 and I see that my friend, Retro, was very pleased with them too :D
Thanks for your lengthy and interesting comment. If you don't mind you can DM me the demo file. Also the E1M8/E4M3/Black Tower all-ghosts footage was staged by manually setting the blockmap width to 0 as soon as I fired a shot. Those positions and angles will most likely not cause the bug normally.
Great work with the analysis! It's always fun to see what happens when numbers precision freaks up in unexpected ways.
5:28
Damn that’s a cool way of getting around that, looking forward to maybe seeing it as another “practically possible” addition in “Doom Challenges Deemed Impossible Update Update”
Thanks, Decino! I was really hoping to see the "crushed enemy resurrection" bug mentioned on your channel! I had no idea there was a separate ghost bug.
I already covered those in the Arch-vile video.
This has happened to me twice on the version I play on my switch. I thought the port was buggy! Thank you for explaining this Decino I never knew this!
I triggered this bug in an unmodified E1M5 in the outdoor slime pool area where the yellow door is. Seems odd because I don't think that map has that many linedefs and things, but I'm sure it was this bug. You just don't forget every bad guy on the map suddenly deciding "hey, why do we wait for the Doom guy to come to us to try and kill him, let's all charge him now!"
The incredible depth of just this one singular human endevour is fascinating.
I find that I have to rewind and rewatch segments of these videos to thoroughly digest the tech-speak. But I do love these analyses! Classic Doom is more multifaceted than I ever would've imagined!
I had specific memories of causing this bug when I was a kid, on Doom 2 map 30.
Now I know why.
This would probably never be as interesting if code analysis was over a more modern game. I'm sure there would be so much to go through that it just wouldn't be that interesting. So yeah, these videos have a perfect match: Doom's code is simple enough to find rather simple answers for known bugs and exploits; game is too old, it is from a time when game development wasn't all that mature to avoid simple mistakes, which is why we still find crazy stuff like many bugs Decino shows in his videos.
Amazing, as always. I hope you never stop finding weird shit in Doom's code
I once encountered this bug many years ago as a kid, playing the secret map of episode 3 of Ultimate Doom, had no idea how it happened but it was cool for a while, I'm not gonna pretend I really understood everything in the video but it's cool seeing it brought up lol.
A friend of mine streamed his first UV Fast clear and the squash-resurrect ghost bug occurred _twice_ on him, was an interesting sight
Been playing Doom since Doom II came out and have never had this occur. Then again, I also stuck pretty close to the original games until only a few years ago. Still crazy how rare this is if I have never seen it happen once! Crazy!
Wow this is so damn good. Excellent research, dude. I really love seeing games inner workings being examined.
This leads to the very mysterious question: "Who asked?" Well, to understand the question, we have to understand the answer: So this very particular question is asking about who asked, the question is divided into two parts: Who & asked "Who" is what is called an "Interrogative word" which specifies the answer to make it suitable for the question, the "Who" here is specifying a person/human/homo sapiens/guy which has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. Second: "asked" is a verb in the second condition of the forms of the verb, which are divided into three types: Regular, Past, or Past participle. and the verb "asked" is in the "Past" condition, which talks about the time that is gone and no longer exists. The original form of this particular verb is "ask", which is to say something in order to obtain an answer or some information. So, to summon what the answer wants from the previous two points, it's that: The answer wants to understand and know about the person/human/homo sapiens/guy who wanted to say something in order to obtain an answer or some information. So, in order to answer this question, we will have to identify two points: First: What was the question that the subject of the answer to the question "Who asked?" asked? Well, to understand this question, we will NOT have to understand what is the answer. We will just have to understand the definition of "Question" The "Question" is A sentence worded or expressed so as to elicit information. Questions could be identified using the "Interrogative Words", which we talked about earlier. these "Interrogative Words" are nine, which are: Who, What, Where, Why, Which, When, Whose, Whom, and How. We are going to explain each individually: As we said earlier: "Who" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. "What" is specifying a non-person/non-human/non-homo sapiens/non-guy who either does not have a brain that he can understand and think properly with, like plants, or objects, or they have a brain, either that their brains cannot understand and think properly, like animals, or their brain can understand and think properly, but their species/type is rather different from the society, like extraterrestrial creatures, so the answer should be as I said in the abstract: A(n) animal, plant, extraterrestrial creature, or object. "Where" is specifying a place, city, country, continent, etc. where something happens, or some(one/person/human/homo sapiens/guy), plant, animal, extraterrestrial creature or object which exists in a place, city, country, continent, etc. "Why" is specifying a reason for doing something. "Which" is specifying a choice of either two or more choices that the receiver of the question usually chooses. "When" is specifying a time in which either something already happened, or something will happen in either near, or far future, for example: "When will anyone save me as I was captured by MatPat for trying to comment a joke about his video?" "Whose" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, and that person/human/homo sapiens/guy owns something, or someone ( if he is a human trafficker ), and the sender of the question is trying to find who owns that something, or someone. "Whom" is an old-fashioned term, not often used today. Many native English speakers are less than clear about its accurate use. In fact, the word serves the same purpose as "Who" questions, which as we said: specifies a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human, but tends to be used when it is the object of the verb. With modern English, there is no real need to use the term. "How" could be referring to the way something is done or refers to the status of the receiver of the question. Now, let's get back to where we were talking: Questions can be different, and many, and the possibility of guessing the question could be high or low according to the frequency of using it, but guessing a question which was asked for the first time is very difficult, so, it is not specific what was the question that the subject of the answer to the question "Who asked?" asked. Second: What is the purpose of the question "Who asked?"? Well, it could be referring to roasting someone as the humor of "No one asked.", and it could be referring to actually asking a question about who asked the question. So, here's the answer to the question "Who asked?": It could be anyone who made something unlikely for the others or someone who asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else. (s)He could be you. (s)He could be me. (s)He could be Elon Musk. (s)He could be even your mom. as long as they have made something unlikely for the others or they have asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else.
Decino, a Doomtuber who teaches us rare bugs that I'd never see.
This leads to the very mysterious question: "Who asked?" Well, to understand the question, we have to understand the answer: So this very particular question is asking about who asked, the question is divided into two parts: Who & asked "Who" is what is called an "Interrogative word" which specifies the answer to make it suitable for the question, the "Who" here is specifying a person/human/homo sapiens/guy which has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. Second: "asked" is a verb in the second condition of the forms of the verb, which are divided into three types: Regular, Past, or Past participle. and the verb "asked" is in the "Past" condition, which talks about the time that is gone and no longer exists. The original form of this particular verb is "ask", which is to say something in order to obtain an answer or some information. So, to summon what the answer wants from the previous two points, it's that: The answer wants to understand and know about the person/human/homo sapiens/guy who wanted to say something in order to obtain an answer or some information. So, in order to answer this question, we will have to identify two points: First: What was the question that the subject of the answer to the question "Who asked?" asked? Well, to understand this question, we will NOT have to understand what is the answer. We will just have to understand the definition of "Question" The "Question" is A sentence worded or expressed so as to elicit information. Questions could be identified using the "Interrogative Words", which we talked about earlier. these "Interrogative Words" are nine, which are: Who, What, Where, Why, Which, When, Whose, Whom, and How. We are going to explain each individually: As we said earlier: "Who" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human. "What" is specifying a non-person/non-human/non-homo sapiens/non-guy who either does not have a brain that he can understand and think properly with, like plants, or objects, or they have a brain, either that their brains cannot understand and think properly, like animals, or their brain can understand and think properly, but their species/type is rather different from the society, like extraterrestrial creatures, so the answer should be as I said in the abstract: A(n) animal, plant, extraterrestrial creature, or object. "Where" is specifying a place, city, country, continent, etc. where something happens, or some(one/person/human/homo sapiens/guy), plant, animal, extraterrestrial creature or object which exists in a place, city, country, continent, etc. "Why" is specifying a reason for doing something. "Which" is specifying a choice of either two or more choices that the receiver of the question usually chooses. "When" is specifying a time in which either something already happened, or something will happen in either near, or far future, for example: "When will anyone save me as I was captured by MatPat for trying to comment a joke about his video?" "Whose" is specifying a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, and that person/human/homo sapiens/guy owns something, or someone ( if he is a human trafficker ), and the sender of the question is trying to find who owns that something, or someone. "Whom" is an old-fashioned term, not often used today. Many native English speakers are less than clear about its accurate use. In fact, the word serves the same purpose as "Who" questions, which as we said: specifies a person/human/homo sapiens/guy who has a brain to think about the surrounding stuff which surrounds him, which distinguishes the person/human/homo sapiens/guy from animals, plants, extraterrestrial creatures, or objects, so the answer should be as I said in the abstract: A human, but tends to be used when it is the object of the verb. With modern English, there is no real need to use the term. "How" could be referring to the way something is done or refers to the status of the receiver of the question. Now, let's get back to where we were talking: Questions can be different, and many, and the possibility of guessing the question could be high or low according to the frequency of using it, but guessing a question which was asked for the first time is very difficult, so, it is not specific what was the question that the subject of the answer to the question "Who asked?" asked. Second: What is the purpose of the question "Who asked?"? Well, it could be referring to roasting someone as the humor of "No one asked.", and it could be referring to actually asking a question about who asked the question. So, here's the answer to the question "Who asked?": It could be anyone who made something unlikely for the others or someone who asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else. (s)He could be you. (s)He could be me. (s)He could be Elon Musk. (s)He could be even your mom. as long as they have made something unlikely for the others or they have asked a question which could be a hint to treasure, or a last "sentence" from somebody, or something else.
This is a very strange thing I didn’t know could happen in Doom, but now that I know it can happen, I am scared to reach the Icon of Sin in Doom II.
I love when Decino makes reviews about Doom. Very interesting.
I think I've encountered this precisely once long ago when I was a kid. I thought I'd somehow activated some kind of noclip mode for enemies and tried to fond out what it was. I'd long since concluded I must have just glitched the game or imagined it.
Am so glad and happy that they're is still people talking about the old doom games it make me proud to make doom maps thank you Decino
This was really interesting I've never uncounted myself but still interesting to see how the code works. Cheers for the upload decino
I'm gonna be honest, in all my years of being a novice I have never encountered this but that aside yes I highly enjoyed watching this my best to you and yours pal as always stay safe Doom guy.
Crazy but amazing somebody has finally used this. Would it be possible to overflow the correct amount to leave the switch rooms block or block line active so it could be used in other levels?
Only possible if the exit switch is in the most Western block of a level.
Love the technical analysis and code deep dive videos. Keep it up!
Every time I watch this video, when you first name it "The Intercepts Overflow" I envision someone telling a scary campfire story, and I can just imagine the pause for effect right before "The Intercept Overflow". Brilliant, haha. Thank you for the DOOM analysis videos!