How Sound Travels in Doom

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[@decino]

Background song now available on Bandcamp: decino.bandcamp.com/album/pumpkin-beats-to-analyse-to

[@neputendo]

I forever love the idea that Demons are basically deaf to basically everything BUT the very very nonexistent noise of punching air across the entire fuckin map

[@TivonSanders]

I guess the idea is that there not supposed to engage even when they hear a battle going on between 2 other monsters. For them to engage means that they're gonna attempt to stop the fight by killing the instigator. If Doomguy is silent throughout the whole ordeal (and out of view), then they're not gonna engage because Doomguy is the one all Demons are obligated to kill. They also might have insanely sensitive hearing. But don't mind me, I'm bored.

[@armansagmanligil1144]

clearly demon attack noises are paired with a ultra-high frequency IFF signal that only other demons can hear

[@jking4854]

"You are talking mad shit for someone in the other side of the map distance"

[@JGT-yd2wx]

IKR? WHY DOES PUNCHING THE AIR MAKE N O I S E?

[@cheesepop7175]

fucking*

[@bauul.]

I remember when beta-testing Bastion of Chaos (an immensely sector-dense level) we found that the chaingun and plasma-rifle were causing massive slow-down. It confused everyone why only these two weapons were having issues, and eventually we worked out it was due to sound propagation: because noisealert triggers every time the weapon fires, the fast-firing weapons combined with the huge level (which featured zero sound blocking lines) were causing CPUs to overload. They couldn't finish one sound propagation check before the next one started. The author, Bridgeburner, put a bunch of sound blocking lines in and just like that, the FPS issues were solved.

[@Dargonhuman]

That's interesting and kinda crazy all at the same time.

[@davidreeding9176]

@@Dargonhuman thank you for sharing.

[@spiderplant]

I was just thinking about a situation like this. Crazy

[@anonracer95]

damn, even with code compiled through C like Doom is, and C is known for running pretty fast and using less system resources, those function calls must have been in the millions or something 😂

[@onepureturtle]

2:12 Quake ended up having this functionality - if you anger a monster, it will also activate every monster that can currently see it.

[@iguana9173]

That’s true. I learned that the hard way.

[@mr.m2675]

while i made my first quake map that was my problem too, i was blaming off grid brushes at first

[@magnusm4]

"Gets alerted outdoors" Thousands of enemies on the moon: I heard that!

[@hallucinationthoughts]

It's honestly surprising how sophisticated it is for a near three decade old game

[@tatsuryuu5227]

Carmack is a genius like all the ID engines made by him are impressive even IDtech 5 even if it's not practical

[@ashchaya7676]

Good efficient code and good design was a pretty normal thing in the programming world back then. EDIT: Not meaning to take anything away from the creators, I'm just addressing the "three decades old" comment.

[@BabzaiWWP]

if only modern devs did this to make their games be able to run on anything

[@mrscruffles801]

Seriously, the absolute resource hogs released today are inexcusable. I like some good clean code.

[@MatthewHolevinski]

@@mrscruffles801 What don't like 450GB games?

[@BigPapaKaiser]

*Doomguy walks intp a room of demons, unseen.* *Coughs* "Oh, sounds like Billy got flu again." *Farts* "Ewwwww Michael, what did you eat?!" *Causes Cyberdemon to infight* "Sounds like Kyle got the bad news. Apparently his wife lieft him for a mancubus during his last deployment to Earth..." *Grabs a running chainsaw* "Carl, is that your stomach again?" *Accidentally moves his hand forward a little too aggressively* "HUH WHAT WAS THAT OMG IT'S HIM!!!"

[@pizzeria_mayhem8736]

(moves hand a little too fast) AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

[@IllusoryMaze]

The fact that sound tunnels exist and I've always seen them but never understood what they were blew my mind. I wouldn't call them ugly, but they're certainly confounding to the player who doesn't know.

[@Dargonhuman]

I recently picked up the entire Doom franchise on a Steam humble bundle and have wondered myself what some of those odd holes in the walls were for - they were too far up to be demon glory holes but also didn't seem to be connected to any secrets.

[@doomknight7559]

I always thought that they were just decoration.

[@btv4120]

I used to clip through walls heaps as a kid. If I recall correctly, you could clip through and walk through those tunnels when clipping. Monsters would see 4 pixels of you and wake up

[@Jukeboksi]

I never even noticed.

[@Titanic-wo6bq]

​@@btv4120 Demons don't care when their fellow demon roars and starts chasing a player they can't see, but as soon as they see 1 pixel of Doomguy's boot they wake up.

[@Chozo_Ghost]

The "squeak" sound when the Lost Soul fell down after crashing into the wall was... strangely adorable. Never did I think I would associate adorableness with Lost Souls, but once again, here we are.

[@stylesrj]

When I was a kid, I always thought the Lost Souls were kinda cute...

[@poweredbyford87]

@@AlphaCarinae I just want a Cacodemon on a balloon string for Christmas :(

[@Dargonhuman]

Makes me want a Lost Soul squeaky toy now...

[@PerFT__GaL]

They are like chihuahuas, cute and annoying

[@TheBeast94YT]

7:15

[@wallyhackenslacker]

I imagine that only player-emitted sounds are propagated due to performance constraints from 30 years ago, but it's wild to think that the id guys considered making demons wake up when other demons make noises. Such a relatively tiny change would have made Doom play very, very differently.

[@InsanityReborn]

>30 years ago AUUUUGH.

[@BlazingShadowSword]

​@@InsanityRebornHow's your back after reading that? Mine's killing me.

[@hrnekbezucha]

Fun fact, 2:22 is how it works in Quake. When an idle monster sees a monster that chases the player, it too will begin chasing the player. So one can easily alert a big portion of the map.

[@iguana9173]

The thumbnail: Doomguy rocking and rolling all night and partying everyday. Zombieman: aww for god’s sake it’s 3am and my ears are bleeding.

[@vaiyt]

Oh boy 3 am

[@Kyezoar]

The fact that the punch can alert enemies without even touching them is hilarious. They get aggravated at the air silently moving from a human's fist

[@unchaynd7266]

1:12 I think that Doomguy is so strong that he creates a sonic boom when he punches the air. Maybe he doesn't hear it because he's standing behind his fist when he makes it.

[@tylisirn]

Should make it so only punching with the berzerk pack active wakes up monsters, otherwise your punches are too weak to break the sound barrier.

[@malfolin]

My Doomguy punching air with so much anger that it alerts demons.

[@IMGH0ST36]

The information given and the amount of his effort is one thing. A decino vid for Christmas is another special treat!

[@orchid9]

It's amazing how stupidly primitive Doom's tech is, everything is super-fake and built with a duct tape and harsh language (because it's the most PCs of that era could handle), but it still approximates the intended result really really nice if you don't look that hard to break the illusion. No miracle it became a revolution - it punches way way above it's height by using smoke and mirrors. This engine is genius.

[@sinkingdutchman7227]

Game Coding has always been about faking your way past limitations

[@EsoiTheGrumpyMawile]

P_noisealert could have had some interesting interactions, lost souls have no alert sound so they may have been intended to never wake up other monsters, paired with how forgetful they are, they could have had some interesting stealth missions involving them. Also Cyberdemons and Spider masterminds play their wake up sounds at full volume... imagine if that woke up every monster in the map.

[@scottl.1568]

Decino even putting in work on Christmas Eve... Either he's the most dedicated KZbinr out there, or he's the heathen! Or maybe it's a bit of both...?

[@gigaslave]

It's the gift of knowledge :V

[@Koowluh]

Or he recorded it previously and set it to release this date and time.

[@SU76M]

Or he lives in Orthodox country, so Christmas will be 07 January.

[@CptJistuce]

@@Koowluh Madness! That's unpossible!

[@HerbziCal]

Seeing someone else doing the football clap tune by humping a wall is great. I do that all the goddamn time and thought I was the only one.

[@DOOMSlayer6476]

I can't believe DOOM is going to turn 30 next year. It feels like the game just came out

[@flextape467]

Old

[@1gnore_me.]

dummy sectors are one of my favorite engine quirks about doom -- you can do some really cool stuff with it once you understand how it works.

[@demogorgonzola]

First of all - Prettige kerstdagen en alle goeds voor het nieuwe jaar! :) The idea that in-game mechanics monster alertness propagates independently of sound makes me think that - lore wise - that demons do not actually hear soundwaves but sense a malicious intent that the Doomguy's thoughts project and that the pull of a trigger or swish of a fist is just a by product of this process. Why do monsters don't care for other monsters' infighting? - because they are indifferent to the fate of their demon brethren, and unless the threat is direct they don't react (a bit like the Borg from Star Trek). Why this information travels along the level for long distances but gets blocked from time to time? - some materials are telepathically active and some block the thought propagation (think of Magneto's helmet for example). It's still my personal head-canon only (and probably has a few holes to be worked on) but I think it's a neat theory. :)

[@Dargonhuman]

I like it. Empathically sensing hostile intent would explain a lot of the apparent inconsistencies of the sound detection AI.

[@NoriMori1992]

That's a fun theory.

[@niconutz898]

The midi at the end is absolutely my favourite one 🔥 got me back into playing the electric guitar Merry Christmas Decino! Rip'n'tear like no other in 2023!

[@KeDe1606]

I‘m sorry, is that a *Doomguy* *Trollface* ?

[@V2_REAL_GAMING]

@@KeDe1606 yes🤓

[@KeDe1606]

@@V2_REAL_GAMING i don’t know, if I should be jealous or disturbed

[@StabilerSerbe]

Is there a full midi or a name somewhere of this? It sounds awesome!

[@asticlol]

what's the name?

[@thehonestabe]

As a software engineer and a Doom fan, I love these videos! Also at this point, I believe decino knows more about Doom than anyone else!

[@TheGuyWhoIsSitting]

I always loved when you punch the air and all the enemies wake up.

[@Dondlo46]

Playing Doom for years and I never knew some maps had holes for sounds, this game never gets old

[@dr.angerous]

It's been said already in many videos idiot

[@Dondlo46]

@@dr.angerous thanks for the information smart guy

[@dr.angerous]

@@Dondlo46 maybe one day you will be less stupid

[@BlazingOwnager]

I never knew why iD left those holes in the walls until now. That's pretty clever. That said, I still don't know why they did it instead of wallpapering the hole with a "transparent" texture or hiding them behind some stuff.

[@Ehal256]

They probably thought it added a nice bit of decoration if you noticed them. I think a texture would make them too obvious unless completely hidden.

[@kveller555]

@@Ehal256 You could actually add the same texture the rest of the wall is using, and with a bit of alignment work you'd be able to make it virtually invisible. It's misaligned, but E1M1 has a wall like that covering a secret hallway above that zig-zag path with the nukage.

[@LonelySpaceDetective]

At the original resolution of 320x200 the vanilla game ran at, you'd probably be hard-pressed to actually notice that these holes were present without already knowing they were there. Especially if your CRT display was not that good.

[@laws1993]

I love the complexity of doom. It's not just a game, its art

[@nich3897]

GOD there are few videos I enjoy seeing in my subscription box more than a decino vid, ESPECIALLY AN analysis one like this. That yellow background is pure dopamine.

[@der_Alptraum]

It has always maken me scratch my head how demons can hear you punch the air.

[@BigMacDavis]

Merry Christmas, decino. Spend time with the pumpkin lady and your family and friends. Have a wonderful 2023. :)))

[@TheGman5000]

Even a doom god needs to rest!

[@wingjaigaming8240]

The more I watch Decino's videos, the more I appreciate Doom. It made me realise what seems like a simple game is actually very complex and full of clever programming

[@halfsourlizard9319]

And full of bugs.

[@waterbreak]

I like how decino makes fun of how demons react to different sound in the game.

[@RedBelmont456]

hey doom is almost old enough to be an all powerful wizard too, man how the years have passed... and this game is still so much fun to play

[@MrDoomquake777]

I love the screaming farting part and the lost soul crashing into the wall! Another interesting and informative video. Wish I had known about it years ago when I tinkered with mapping. It took me a bit to figure out how the sound blocking lines worked.

[@Kirmakoff]

Thanks for the vid and merry Christmas, you majestic pumpkin man! Never thought sound propagation was this complex - traversing sectors recursively is a pain for memory. But I guess it brought an incredible level of immersion and realism to the game, unseen in Wolf3D

[@violentbeetle2441]

It's worth remembering that sectors in doom map are defined by the lines on their edges. The sector data has no information on x/y coordinates, instead lines have information about which side has what sector. As such, it should be pretty easy to identify which sector borders which - just by checking who shares the line.

[@SpaceClick]

Believe it or not, Wolf3D also had sound propagation, in fact I am willing to bet that it is the reason that Wolf3D exists in the first place. Why? Because the game Wolf3D is based on, "Castle Wolfenstein" (1981) ALSO had this feature. It was this wiz-bang sound propagation feature that made the game so popular at the time (the first time it was ever done), and I would bet this feature is a big reason why they wanted to remake it (I know it is the main reason why I remember the original game).

[@Roxor128]

@@SpaceClick Wolf3D's approach is brilliantly simple. The game defines a bunch of floor tiles that all look the same, but when you make a sound, any enemy that's on the same type of floor tile will hear it. If you have two disconnected rooms with the same floor type, you can have the player's fight in one room alert enemies in the further one and they'll make their way through other rooms looking for the player without the enemies inbetween responding. It's also got ambush enemies that'll only go after the player if they see them, too.

[@immortalzealot9725]

So those strange black squares have been answered. One of the bigger mysteries.

[@lhfirex]

Great video! Now we know that Doomguy's fist wakes up the demons because he's yelling along with the MIDI, and they get angry because they want to get back to sleep.

[@CptJistuce]

He canonically yells "RIP AND TEAR" when he punches, I believe?

[@Jukeboksi]

I'll buy each of you a beer of your choosing

[@magnus0017]

The editing in these is getting real good, nicely done. And always fascinated by a cool, complex thing Doom did long before it ever became a common thing in games.

[@JangianTV]

You know you're in for a good time when you see that yellow background! 😊

[@droogie1991]

Ever since I first played Doom II’s entryway (seems like a lifetime ago) I’ve wondered why in that secret room there was that black spot in the upper corner. I thought it was an error/mistake but now I know!

[@stylesrj]

Same.

[@violentbeetle2441]

I remember when I just started mapping, I got confused by sound. Turned out Doom Builder 2 that I used at the time, by default didn't split sectors if you draw a sector through them - for example if you draw a doorframe first and then draw a door in the middle of it. As a result all my doors let sound through. I still like to use this trick sometimes, pretty cool when you start a fight and monsters open the doors from the closets they were napping and walk in to join the fight. You make ambushes more interesting by blocking sound propagation into a teleport closet with a door hooked on the same trigger as regular advancement - then you open the door and see monsters. You start fighting and then reenforcements start teleporting in. Another fun application of this technique is what I would describe as cacotube on trigger. You can put flying monsters (cacos, lost souls or pain elementals) inside a pipe extruding from the floor. It's too tall to fall into from the ground, it might even be something like a tree reaching above the eye level. If you fire a shot - cacos will wake up and float out of their tubes - but this can potentially be cheeses by shooting making them wake Now sound from surrounding area won't up early. But you can turn both edges of the tube's wall into sound-blocking line. Then you can join the insides of each pipe with a sector that is a closed door, which in turn connects to a sector joined with outside of the pipe. Until some of your action opens the door, the cacos can't hear you, even if you are right next to them.

[@SiFi270]

I wonder how much more complicated a video like this but for Strife would be. One strange thing about it is how one enemy can realize where you are just because they got hit by another enemy's hitscan attack. I'm pretty sure it's to do with the developers trying to rework infighting, because in Doom you can remove the "shootable" flag from a Cyberdemon with DeHackEd, then go to the room with one in Tricks and Traps, and each Baron will respond to being hit by a Cyberdemon by targeting the player. Maybe I'm not explaining it that well.

[@RetroGamingWithEdgarRivera]

1:12 hahahahaa a loud chainsaw doesn't woke up the demons but a fist in thin air sure does lol XD Jokes Aside amazing Doom analysis video video as always my friend it's always a joy to learn new things in Doom specially for an amateur player like myself.

[@BPKPhoenix]

I'm ALWAYS ready to learn something new when it comes from decino, its like that one teacher in school that you love learning from even when you hate school altogether. This was interesting as always, Merry Christmas, decino! \o/

[@thebaseandtriflingcreature174]

Shoutout to AGONIZING RECTAL PAIN for being with us for this long

[@karlk5801]

AGONIZING ORAL PAIN is a mere imitator, doesn't deserve first billing, should change his name to PAIN IN THE ASS

[@DrakonLameth]

I was curious about that little corner nick in that closet in Doom 2's first level, so I'm glad this video finally answered what that was for me.

[@clairecelestin8437]

I've seen those sound tunnels for 30 years and never knew what they were. It all makes so much sense now. Thank you!

[@coryfusting9294]

Seconds later, the Zombieman in the thumbnail gibbed from all of Doomguy's riffs

[@fmsyntheses]

Only Decino could both remind me of my impending death from being elderly and entertain me this much simultaneously.

[@Doctor_Spengler]

Fart jokes are based.

[@FirithPanda]

Pumpkin Man blesses us with another Doom mechanics video on Christmas. I shall sleep good tonight.

[@an0malyops59]

You make all these videos about this wonderful game. Then I remember the geniuses that worked on it and why it behaves the way it does!

[@johndoe7270]

Monster's wake up noises waking up other monsters would an interesting difficulty modifier,

[@OmarHyari2009]

As soon as I saw a notification for a decino analysis video, I clicked immediately. Edit: that aging Doomguy at the beginning is really cursed Maybe a bit too much

[@iguana9173]

That went too far.

[@XzMondayNightzX]

We know what the holes in the walls are for now but what about the hole behind the cacodemon? Is that also some form of sound propagation?

[@BenAkenobi]

You probably shouldn't check the video by a certain Mr. Icarus then

[@harrywagner9532]

SOMEBODY GET THIS GUY 1M, no but seriously his content is amazing and i love it he was the one who originally made me buy doom on steam and then beat it, i was really intrigued by the amazing codeing and mechanics of doom, this guys work is insane and when i checked his sub count i was suprised at the fact that he only had 170k subs (at the time of posting this) but more so compared to others channels that havemore subs then him some of those poeple have content way under the quality of this guy.

[@machinatingminotaur6285]

huh, really makes you wonder if they had deeper stealth mechanics planned originally

[@LonelySpaceDetective]

It seems unlikely to me, considering Wolf3D had reasonably extensive stealth mechanics at first (matching its spiritual predecessors) that later got gutted for dragging the pace of action down.

[@lostskull7467]

Loved the snore of the lost soul going back to sleep 🤣🤣🤣🤣🤣🤣

[@hitmiccs]

6:07 oh. my. god. You just explained the one black texture in that tiny room I always saw but didn't understand the purpose of. After 3 decades I finally know... thank you, decino :)

[@BlazingOwnager]

I posted a comment about co-op curiosity, only to have it immediately answered. Absolutely the best Doom breakdown channel on the internet, of all time.

[@general0mega]

Thank you thank you thank you! for being the guy to explain why lost souls forget what in the hell their job is. Cheers and happy holidays!

[@King_Firebrand]

Finally, after all these years, I understand these little tunnels and holes in various walls. And why lost souls sometimes charge past me, hit a wall, and stop caring for me all of a sudden. Thanks a lot for these videos!

[@Saver310]

Merry Doomsmas, Decino! Thank you for still digging interesting things in Doom!

[@Roge9]

John Carmack is a genius

[@antmoundsock1122]

It makes my day when another Decino analysis video comes out. Thank you for this amazing content and merry Christmas!

[@ClearlyNOTaFedandNOTatiktoker]

I love how a loud-ass chainsaw is not drawing the attention of a demon but you punching the air it wakes up every demon around you

[@Icelink256]

Wow! I had no idea that there wasn't a length limit on the sound propagation! I'd always assumed that it only checked the immediate surroundings...

[@Rad_Dan]

Feels like a slightly early Christmas present, getting this Doom knowledge breakdown today. Thanks Decino

[@sonicdoommario]

I feel I was pretty well-versed with sound in Doom, I think the only thing I didn't realize was that it's the sector that will remember if a player's sound has reached that sector and not the monster "hearing" the sound. That thing in the automap towards the end of the video, is there a source port with that feature or something? Does it show like which sectors have had the player's sound travel through them, or when you fire a weapon, it will show which sectors that sound will be able to reach from your position? Feels like a pretty fun feature, if it exists.

[@decino]

I made that animation myself, not a source port feature.

[@karlk5801]

@@decino How tho? Too big to record yourself doing by hand, too faithful to the map to be all code-generated. Did you borrow the map display code and the nodes from a doom wad and add your own coloring?

[@decino]

I modified the automap code to make the animation.

Thank you decino, this is exactly what I wanted for christmas 🎄

[@hutprancer]

Very enjoyable video! I would have thought simple deep recursion here would be too much for hardware of the time but I guess not! Thanks

[@Florian0799]

Ah now I know why sometimes I see seemingly random tiny tunnels in maps.

[@St00rt]

Compliments of the season to you and your family Decino. Thank you for another year of epic videos. Here's to a wonderful 2023.

[@ClippyClippington]

Decino I gotta tell u Im pretty christmas loaded right now but man these videos are GOLD for map makers getting creative ideas bud cheers

[@laurenhahn8569]

I love the charming little animations you put in your videos!

[@itmcbhpbgf.6374]

thumbnail: DOOMguy is playing the classics... and the demons hate it.

[@christianjonker8181]

These thumbnails just keep getting better and better!

[@TheGamerUnknown]

Absolutely fascinating! Thank you so much for showing this. As a programmer and enjoyer of games, it's so fun to see these behind the scenes explanations.

[@starry4471]

He never forgot about Anagnorisis. Your playthrough of Eviternity basically got me into Doom, and I have since beat the WAD myself. Thank you Decino!

[@Moleoflands]

Imagining a puzzle/stealth combat map with the following mods - Punch makes no noise - Enemy roar wake up other enemies. Then give the player a berserk. Pretty sure pain state skips wake up noise, right?

[@lenin17301560]

I definitely was in Santa's good list this year, getting a new Decino video for Christmas. Thank you so much for your awesome videos.

[@miroslavzima8856]

Another amazing video which topic I wouldn´t even guess. Merry christmas and I wish you a lot of inspiration in upcoming year!

[@Razgard]

That's something I have never ever thought about. Very interesting, as always. Merry Christmas, decino. Thanks for your work.

[@TheRogueWolf]

1:31- "...what's he doing to that wall?" "I... I don't know. Just ignore him and hope he goes away."

[@spectral1064]

I really really love your videos and I think they're super well made. I enjoy the editing a lot and I think it's cool seeing Doom's code broken down :3

[@BassSlapper89]

The Christmas gift we got! Doom Analysis video! Thank you Decino. Happy Holidays everyone

[@sakurasfingernails7247]

I appreciate the willpower it must've took to not make the thumbnail the boomer on a lawnmower meme

[@themartonjanos6194]

I love how the outro music is the KoD track ZeroMaster Fast Monsters No Damaged the Okuplok Slaughter Map to.

[@gregmiller7224]

Wishing you a Merry Christmas, Decino. Thank you also for this Christmas gift of an analysis video. 🎁🎄

[@Doctor_C_Jack]

I have always wondered what those missing corners were. This is a very interesting topic and I am glad you covered it. I learned a lot from this video.

[@_vez]

It's always nice to see these analysis videos

[@UbergamR447]

love your videos, great explanation! im fascinated by the doom engine since i got a sneek peak how it works through your videos, much appreciated! :)

[@EmApex]

a pee noise alert is something I always try to avoid when I go to the toilet

[@Funfan1992]

wow it's been a few years that you talk about the game Doom in the technique is what impresses me is that you always manage to find a new subject

[@sailor_jupiter_6823]

Ahhh, a yellow thumbnail decino video. The best Christmas gift we can ask for.

[@RevolverRez]

Now this is some good Christmas content! Merry Christmas, pumpkin man!

[@Portponky]

Hooray! It's a Christmas miracle, I requested this topic a while back. Highly informative.

[@colemarshall0020]

dear decino, you make AMAZING videos, i still have no idea why are they not reaching a lot of people. you do solid work, keep it up!

[@bolson42]

The removal of other demons being able to yell to others, a long with a lot of other things lost in different versions of the code really makes me want to see a modern version of doom, with basically the exact same physics and mechanics, but just polished to an incredibly high degree and with their original vision. I know it probably won’t happen, but it would be really cool.