Programming a first person shooter from scratch like it's 1995
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- Опубліковано 28 кві 2024
- 3D like you've never seen it before!
PATREON: / jdah
TWITTER: / jdah__
CODE: github.com/jdah/doomenstein-3d
GITHUB: github.com/jdah
EDITOR: NeoVim
CONFIGS: github.com/jdah/dotfiles
THEME: gruvbox
RESOURCES:
* DOOM Game Engine Black Book: fabiensanglard.net/gebbdoom/
* @Bisqwit 's video: • Creating a Doom-style ...
* Fabien Sanglard's "Build Engine Internals": fabiensanglard.net/duke3d/bui...
* DOOM source code: github.com/id-Software/DOOM
* The DOOM wiki: doomwiki.org/
0:00 Intro
0:47 Why?
1:21 Wolfenstein 3D-style
2:55 DOOM-style
9:50 Level Editor
14:35 Proof of Concept
15:53 Outro & Thanks - Наука та технологія
I find it very interesting when developers challenge themselves by not using existing engines, frameworks etc, this looks super difficult so props to you!
The only game I can think of that uses its own engine is HROT which uses its own pascal engine
SDL.
@@monad_tcp Doing a basic TLS implementation actually isn't that bad, mostly just a lot of learning about cryptography and reading RFCs and stuff (and I imagine you're no stranger to that). I'm doing a similar "full stack" project right now. I'm more or less done with TLS 1.3, but I still need to do an ethernet driver and TCP.
I'm developing my own game engine in my channel.
@@monad_tcp I wouldn't write anything
like that myself to be honest, waaay too big of an opportunity for critical vulnerabilities when you're making something that is touching the internet at the lowest level.
I started to learn programming 3 months ago. I cannot imagine myself writing a single line of whatever black magic fuckery you did in this video. Seriously, to me, people that can come up with stuff like these are geniuses
I'm 2 years into a comp sci degree and honestly same. His code looks like math equations instead of programming to me. Love watching him do this amazing stuff though.
Now think of what kind of geniuses were those programmers in the 90s who were first making 3D games and writing frameworks for it.
making 3D games or 3D software is the most difficult thing to code. It's the highest level of programming. Also at some point you start using OpenGL or DirectX functions.
@@tealtrim9747 Once you get into 3D programming and low level, everything is just math equations... Some of the videos I have made on 3D stuff just needs hours of explanation. If you want I can hook you up with an explanation I made of basic raytracing.
@@inlandish I am not very good at math, I should probably just stay away from the more mathy areas of programming. I appreciate your offer though, I just don't want to waste your time because I'd be too dumb to understand or properly utilize what you teach me.
This man is a coding monster
legit
@@Danuxsy Huh "dOiNg SoMeThInG UseFuL lIkE Ai RESeAcrch", AI research is super different then doing stuff with low-level system languages (like coding in C and C++) and bare bones hardware (Making my own GPU ect)
@@Danuxsy Because people have their own interests and aren't purely motivated by what you deem to be the best use of time.
@@Danuxsy who tf said that we should all be focusing on birthing AI? the knowledge he has has nothing to do with AI, the guy is coding his own engine from scratch. but of course, it's clear that you don't have much experience in the area
@@Danuxsy because not everything has to impact the world to justify its existence
What a mind-boggling project. This man is a powerful programmer. I aspire to someday come close to his level of speaking with computers.
You have to consider that he definitely did his fair bit of research on how to do it. Back then, these 2.5D/3D games were groundbreaking for a reason. The maker of this video didn't invent the algorithm, he is just building what other people did before him and that information is widely obtainable through the internet. Not to play down what he did, it's still amazing work, but that doesn't mean he is a god programmer.
For me, there is comment of guy just below your comment who states that some part of this video looks familiar to him because it was something he already did. Thankfully name of that guy is mentioned in description and he was thankful for that.
Yep 3D software /games .. the most advanced programming :)
I see this project as less of a display of a programming prowess and more of a display of math prowess.
Yeah same
The biggest jaw dropper in 1990's programming is the use of mathematical tables in memory and other tricks to cheat calculate results rather than relying on C or C++ math libs to do calculations in order to optimize for speed. Also, they were limited to using very little memory. Lastly, the display functions were mostly written in assembly to also optimize for speed, and that was a bitch to do. People like Ken Silverman and John Carmack were absolute beasts with their respective engines.
Rollercoaster Tycoon was written entirely in Assembly.
Thanks for the mention (in the video description!) Some of this looks quite familiar. Especially the part from 7:28 to 8:06.
hey! I've been a fan of yours I think since before that video was originally uploaded :) your code was a fantastic reference and obviously the tutorial visuals stuck in my head.
IIRC my approach differs in that I ended up projecting walls according to a conversion of their angle relative to the camera (basically -HFOV/2..+HFOV/2 mapped onto 0..SCREEN_WIDTH) whereas I don't think I ever fully understood the method your code uses - it was a good reference in the start but I think the only way I could fully understand things was working out the math myself!
When two masters colide.
@@jdh IIRC, Biqswit uses the regular old z-divide to achieve 3-D perspective. Your approach and his work effectively the same way and are based on the same principle, the triangle congruency. Doom uses a similar technique to yours, to "project" the view-space angles of the wall endpoints to screen-space x-coordinates--albeit with the help of a pre-calculated lookup table for trig functions. Anyways, great content! Loving the aesthetics of your gfx engine.
A huge flex would be making this able to build for 486 platforms like the original DOOM, so you could play on period-accurate hardware!
that's part of the plan! I had originally even used fixed point Q16.16 math for the project just so that it could run on things without an FPU, but it got too tiresome when it started expanding. when the final game is done though I do want to backport (if you can even call it a "backport") it to MS-DOS!
i initially thought he was gonna make it on dos with 486 hardware 😢
@@jdh I call that a demake
@@jdh where's full game i want to play it
Doom actually ran on a 386
It's really quite interesting to see you come up with all these fun challenges
Especially when nowadays literally every game dev chooses to use a game engine, making a game from scratch is a topic that no one really talks about
You might be surprised by the abundance of games that roll their own engine. It's still a pretty common practice for a developer to make their own engine from scratch, especially when they have particular requirements like performance or rendering techniques.
That being said, most custom engines are just your basic old 3D or 2D renderer, what jdh makes is on a whole level of its own.
@@bluesillybeard I am aware that many games are made with a custom engine
It's just that people don't talk about them a lot and there's not many devlogs about them
Then there's jdh of course...
@@BLAZE_GLITCH there's thinmatrix as well. Major game devs won't show off the internal working of their engine, that's trade secrets, tech demo are also rare.
@@Kabodanki doesn't thinmatrix just use unity tho?
@@thezipcreator no. He either uses his own game framework or lwjgl
"Programming a first person shooter from scratch like it's 1995"
in 1995 Rare was creating Goldeneye for the N64 on SGI workstations, not a kind of 3d doom clone, that is insane to think about how quickly computer technology was moving at the time.
They were using SGI workstations, but the programming of the game engine was still mostly done in C and a bit in MIPS for optimization. SGI workstations came with their own C compilers on them, and the GCC was also installable.
Incredible work. Here’s a tip you didn’t ask for. To get that smooth stepping texture mapping look, you’ll have to subtexel correct each vertical scanline. Just passing this along because it took me a while to get right
What a coincidence! Just a couple weeks ago, I started on my own doom-style engine using Bisqwit as a reference. For my engine though, I went entirely with vector based graphics. I also, in accordance to 90's standards, only used Borland graphics interface. I definitely have not made as much progress as you, but I think we're trying to reach different goals. Regardless, great job!
I actually think the ray traced lighting gave your engine a really unique look! What an awesome project!
As soon as you got the lighting and pallettization in I instantly grew jealous that I will likely never make something that nails this aesthetic so well in my lifetime
I think he’s got sample code and other support material. He mentions it at the end of the video. Your dream is within reach!
babe wake up new jdh upload
More jdh! Honestly, I am sad to see the robot botanist go, but its nice that you can move on to some other projects, and continue to learn! Any chance we could have the Alpha of the robot game to play around with?
1:47 I never gave much thought to software rendering, but that caught me off-guard! A buffer of pixels is all it boils down to. Incredible!
You are a monster, man, really.. I was looking for that kind of content for a long time.. a real programmer working on a doom coding the old fashion way... Of course I learned something like 1% of what you said but I really like those kind of videos where people show the fundamentals. Thank you
this is absolutely mind blowing i hope to be half the dev you are one day man
Wow, above and beyond, way to go! Amazing work, subscribed and looking forward to more videos! 👏👏👏
Looks like a fun project. Thanks for showing!!!
to make the movement more smooth you should make the direction keys accelerate the player rather than set the velocity to a fixed amount (like it looks like you're doing). it really adds a lot to the feel of moving around!
anyways, nice project, i look forward to seeing it develop!~
The length of this video was criminally short I need more jdh😂🧟♂️
agreed
love it ! great video hope to see more like it
Awesome job and as always well presented - thank you!
Damn man this is so cool, I'm so jealous. I went into programming, starting with C, to one day be able to code games like Doom, Half Life and the likes, and the furthest I ever went was a Wolf3D clone. I suck at math and I wish I could understand 10% of what happens in a portal-based rendering engine like you wrote. That's awesome! And I'm so glad you used plain old C.
it actually isn't super complicated! I strongly recommend Bisqwit's video (ua-cam.com/video/HQYsFshbkYw/v-deo.html) and Fabien Sanglard's "DOOM Engine Black Book" (fabiensanglard.net/gebbdoom/) - they make it very easy to understand
@@jdh Yes I know Bisqwit's videos quite well and I have both Black Engine books! I think my issue is more of a motivational one. You're inspiring tho!
The doom black book is great but it’s too high level and doesn’t go into details (at least with topics like how it does texture mapping)
So you are left with a lot of questions unanswered
It will provide a formula but I had to actually look at the doom source code to see certain things related to texture mapping but I still get quite confused. It’s just drawing a vertical column but I haven’t been able to wrap my mind around how it decides what texture columns to draw. But then there’s a whole ordeal with texture pegging which I don’t understand either
Haven't seen the code yet, but based on your explanation at 13:09, there is a chance that the player could clip through a vertex defined on an adjacent "block" if they're going fast enough. A quick fix would be to check every block's collision that the movement ray intersects, with a ray-intersection function similar to the one used in the Wolfenstein prototype.
Looking forward to Spinach-Cat-Banana-Game getting its well-deserved release!
Or you could just cap the player's speed.
@@nikkiofthevalley Unfortunately it's not that simple. Let's say a vertical wall spans the height of an adjacent block about 1mm left of the right border of its block. The player could be **very** close to this vertex, but still stay outside of its block because it hasn't crossed the block's border yet. If the player is 1mm right of the border, and the wall is 1mm left, then if the player moves >2mm left in one frame (not very fast at all), it'll clip. That's why we need to check whether the movement ray intersects with any other blocks.
good catch! I didn’t mention in the video, but the code already does that - it uses the exact same DDA “line drawing”/graph traversal algorithm as the wolfenstein demo just like you mentioned!
@@jdh Great! I mention this because I was working on a similar engine (in ES3 javascript 🤮) and the player kept clipping through borders of where the BSP was set up. Took me about a week to figure out, and by that point I had lost interest. Love your content and your dedication to making your own game engines.
You sharpshooting me, boy? - jdh
waking up to a new jdh video slaps harder than will smith 😁
Thats true
It feels like that happened 3000 years ago but it really didnt
Too soon.
Stfu dead meme
Smith was still in the right, that guy that made the joke is just a bland asshole
See, this is why I love being able to code. You don't need anything except a creative mind, an internet connection, and a laptop to build entire worlds.
You kinda need one more thing though: Time.
@@tonig2757and lots and lots of patience
you don’t even necessarily need internet if you do everything locally
@@Todomo I'm a software dev, which means that at least half my time is figuring out how I should do the things I want to do on the internet.
Internet is the only thing I don't have 😂😂
That's awesome. I'm doing something similar in Rust for a web browser. I also had the same issue with fixed point math and switched back to native fp. Best decision ever. Rust basically walks me through the bugs to fix them before even running it. I should make a video. my render objective is to show how you can make an entire render using trigonometry knowledge from school. I'm using Permadi's raycasting tutorial and the Wolfenstein engine Black Book as a base. I run it on WASM in the browser. Keep it up!
I love these kinds of videos, and also the mention of another youtuber I watch "Bisqwit". Pretty cool time rewind vid
Loved this. This is my favourite combination to code with, C and SDL. I never did do Doom, but I did do a simple ray caster which was fun.
As a long time fan of the channel and seeing as I’m learning C++ for my University degree, including SDL, this video was very interesting to me! Keep up the good work!
The ray-traced global illumination could go in as well. It would give your game that uniqueness! Great video! 😊
I like it. After I learn the basics, I will study this one as I ramp up my learning.
This is very impressive, I couldnt imagine trying to do all of this without a graphics api like DX, opengl or vulkan. Very cool, thanks for this awesome video
Man, I hope one day I could get to your level of coding sir. Really awesome videos!
Just stumbled on your channel and as a budding game developer I can honestly tell you I do not have the patience or the maths to create an engine from scratch. This was a good watch.
At the moment you try to build some real-time graphic stuff up from scratch by yourself you can notice this channel is finest jewelry.
Great video, love it. Its nice to get a good overhead look of something so complicated and interesting.
You, sir, are brilliant! ❤ I enjoyed this video so much!
dang i have been having trouble making a 2d game in c++ recently and you make 3d look easy
would love to see that 3 hours video, if you decide to release it
Well the live editing experience is way ahead of what is available in the mainstream engines so kudos. They could learn a thing or two from you
This is great. Please do the 3 hour video. I recently started learning the arcane art of graphics. Lots of geometry math (as to be expected) but satisfaction of creating virtual world is immense.
Whats crazy is that the coding shots aren't even sped up.
When I watch jdh's videos I always end up wishing I was as good of a programmer as this guy is. This guy can just make whatever he wants. This guy is on a level that most non programmers think you can get after you study programming for a couple of months.
You too can get there if you're motivated and have a few years
It's not really about programming skills, but mathematics skills in this case, I'm programming using C++ for years now, but when it comes to reinvent the wheel like this guy did, I'm pretty sure I will get quickly bored and just throw away the project in the trash can lol !
@@K3rhos Linear algebra wasn't hard for me in university. I will definitely try making 3D games in OpenGL but I highly doubt that I will be as successful as this guy. Because he seems to possess big amount of knowledge of so many different topics. He built his own PC ffs. He built his own OS to run Tetris. He made Minecraft from scratch in a couple of days. I can't make anything serious in a couple of days without introducing bugs.
Love this video format. Awesome content
dang your level editor really made me smile, great job man! would love to see a 3 hour version, just sobscroobd!
You can also fairly easily add mirrored surfaces. Just make sure you don't keep reflecting off of nested surfaces.
Max number of bounces enters the chat
I found myself exhausted after imagining how much work has been condensed into a 16 minute video. Insane.
Nice to see you upload again
This is great! I wish we could see John Carmack react to this, lol
People are saying "don't program your own game engine, they already exist, it is waste of time" and then somebody actually creates one and makes a YT video about and everybody is like "holy shit, that is amazing, you are so good!"
Nice work, btw!
For most intents, a off the shelf engine like unity, unreal or godot works just fine. Btw i am watching this as i was thinking about doing my own engine (for calculator games so that's why)
@@attilavs2 Yeah, for a production game a real game engine is a good choice. However, making your own engine for *learning experience*, or for obscure platforms like calculators :D, is what I want to do as well.
@@abuk95 Not only production games, if you have like a creative idea and don't want to spend too much time on the codey bit, or want fancy graphics, or even just limited by time. Btw if you want to try calculators, it's pretty cool with the latest ones you can run basically every 2d game and stuff like doom ect... Basically a 1993 computer in your pocket, and on which you can have almost full acces to the hardware, especially on Casios
@@attilavs2 Cool! Could be an interesting project to try out.
really blows my mind how much work and knowledge went into creating these games back in the day. and they did it all without google or modern code editors
Super well done video - with the exception of that maddening music loop.
2:49 “Coding like it’s 1995”
Uses const
I often end up seeing these videos pop up and feeling quite inadequate / imposter syndrome.
This is the best "let's code" style video I have ever seen. Instant sub
that looks so awesome you're an inspiration fr
Thank you. This video appeared at exactly the time in my life that I needed it most. That being, the time I've started thinking a lot about how 2.5D shooters work under the hood. It's something I personally associate more with Dark Forces than with Doom, but it's got that nostalgic smell either way.
the term 2.5d makes me want to die
@@iambored1528 so then explain to me then how the doom source code which is publicly available is actually not 3d and explain how it is 2 dimensions and a half since clearly you think public source code that you can read and compile for yourself, isnt 3d.
@@iambored1528 That is completely false and can be proven by looking in the source code. So now I know that you have no clue what you are talking about and are making up stuff that goes against widely available facts. plus you can't have floor and ceiling height in ray casting.
Doom uses binary space partitioning, btw.
@@iambored1528 No, i am saying that it is open source meaning you can read the code yourself and see that it is 3d. but you are instead to lazy to do that and are now lying in a youtube comment section
@@iambored1528 height would be another dimension, making three dimensions. you are literally proving yourself wrong but refuse to see it. and again you refuse to look at the doom source code which proves you wrong. why are you intent on lying to people?
You should implement this engine for your 8-bit CPU 😎, or even a 6502 computer, then you'll even be playing on similar hardware.
But honestly, great video, and very interesting project. Usually people only make the original Wolfenstein style raycast engines, but not the DOOM one, so this was pretty informative and fun to watch.
a 6502 would have to be overclocked to oblivion to implement this (and you'd also have to write a full floating point emulator). I think you meant i386?
@@thezipcreator True, but I think I've seen demos of doom/wolfenstein like games running on the Commodore 64 and other 6502 hardware? (Though I may be wrong). I was just referring to that, as it was much more similar to the CPU he built than i386, and would present more of a challenge.
there are tentative plans for an MS-DOS/486 port in the future!
@@AstroSamDev looking at it, doom on the c64 looks extremely laggy and unplayable, but it's still impressive that it was done.
Doom got it's speed from several really nasty tricks, most notably modifying the executable code to draw walls as it was drawing. Not that I think jdh can't do it, but it's fairly different to what he's done so far.
Bro you’re jacked… 3:50 my bois arms looking filled with coffee and creatine💪🏼💪🏼
The collision sliding is worthy of showing off.
I kinda got stuck on that when I did my own wolf-style engine for fun.
Not sure if this is asked before, but how long did this take you to make?
Very cool!
People who make a game from scratch deserve all the respect in the world. Good job!
First time seeing your channel, and just wanted to say really appreciate the neovim configs.
Dude I am so jealous that you are able to do this; I've so often wished I could program my own engine like this and build a game completely from scratch...
Me in 1995:
OMG this feels better than real life
You should try and get some sort of sound propagation / resonance / reverb system going, like steam audio! Way too modern for a 90s engine, but it seems like one of those cool areas where you could blend the technology together :)
Definitely going to happen! DOOM has some pretty cool sound propagation stuff but it's only used for alerting monsters IIRC
Uhm, look at the OpenAL source code?
I saw many implementations of doom, but this content is awesome.
it's genuinely impressive to me how you're able to focus so long on a project and implement stuff like that. i'm studying software engineering and I'm worried I'll never be able to do that
Can't wait for the among us dating sim
I used to think I was a good coder. Then I found your channel. wow
This is amazing ! Congratulations !!
I've followed along with hour long videos that explain what you just did in the FIRST THREE MINUTES ALONE. Amazing. :)
I'm a simple man, i see jdh uploads a new video, i click.
Bring us Among Us dating sim next please
I always complain about UA-cam becoming oversaturated and "I miss 2019" and then UA-cam is like BAM, new jdh video. Chill, but still entertaining. Keep up the great work!
Thanks for this video, eagerly awaiting the next vid. :D
haven't seen you use Rust on your channel, have you ever considered making something with it or trying Rust? I think you'd feel at home thanks to it being fairly low and high level both, while also avoiding bugs early on with memory management :)
a classic, to be remembered for generations to come
a day when you upload is always a good day. Keep up the fantastic work :)
My favorite thing about the portal based engines are the non-euclidian spaces, as seen in many Marathon multiplayer maps.
Hash tag coding goals. Great summary, well done.
This is incredible.
Pretty cool to watch you coding essentially 2 decades worth of tech progress in a single video. Having lived through all of it, it's refreshing that those younger than myself can learn it all from published sources instead of the propriatary secrecy which was the 80s and 90s.
Thank you, I find the building af the engine much more interesting than whatever gameplay.
this is very interesting to me, expestaily because i really enjoy playing doom, and making levels in it.
8:20 "The code is a little more complicated than ill go into in this video"
A.k.a.: "I have no idea how the code works, just copy & paste it and pray it works"
love the use of ImGui for the custom tooling and editors!
We were spoiled when SDL came out. Before that we had to interact with video memory and double buffering ourselves. Love the video!
Glad to have you back MISTER
Sometime I see your video's pop up and feel nothing but sympathy, like this is so much work.
Me too?
insane absolute gods that came up with this stuff. it took many decades to get to this point though. the first "3D" game was made by some nasa guys back in 1973 called maze war which was also the first multiplayer game. It's mostly wireframe though, but it looks 3D, and you probably know about this already.
Was legit thinking about you today and hoping for a new video. My wish was granted
It's a cool video, i like to watch your videos where you explain smth. Thanks a lot for that!
Love your content ❤ this is pretty rad stuff
I am floored. Well done, sir!
Kinda dig actually. You've really captured the feel of those old DOS games. I think its the lighting. Regardless, well done.
Its kind of wild that someone had to think of all this in the first place. Really makes you appreciate someone like John Carmac