Let's Program Doom - Part 1

I might be the most excited about this video. I really wanted to learn how the original Doom game engine works. l spent a long time learning the basic concepts but created the code myself from scratch and how I wanted to design it. You can follow along or convert this code to any other programming language since I kept it simple in C that draws a pixel at x and y coordinates.

Let me know if you enjoy this series! Thank you for all your great ideas and I hope to see what you make from this tutorial series. Send me a link so I can share it in part 2!

Starter code: 02:28
Drawing dots: 05:52
Drawing a line: 10:38
Drawing a wall: 11:51
Sectors: 15:40
Surfaces: 20:31

[colonelbarker]

I can't tell you how much I've enjoyed this tutorial. It was clear and to the point, but thorough and at no point did you skip/handwave anything important or get too bogged down on details on the basics. Really well done.

The demo videos showing the concepts were really clear

[sircalvin]

one thing i love about your videos is how you keep them language agnostic. you specifically mentioned it this time, but a while ago i followed your raycaster series in js and ended up making a multiplayer arena shooter that could run on my school computers and played it in class with my friends

[joncorso]

A cat is teaching me programming, we truly live in amazing times.

[mr.pavone]

1:30 Sectors were what gave me the most trouble when learning to make Doom WADs. Turns out you're not creating walls when you define a sector, you're actually defining the empty space. So making a room in Doom isn't so much about building the wall but rather you're carving out a space from a chunk of...solid stuff.

[elgentidwell]

oh my god, thank you so so much. For the longest time I was trying to find someone programming a doom-style rendering engine so that I could better understand how it works, thank you for making this!

[elimgarak]

While this is not actually how Doom works, this video is full of valuable insight and techniques, and very well explained. Thank you very much.

[fukkenPavlo]

I got clickbaited, thought cat would explain how to program doom

[KidLeavesStoop]

Such a great video, the math, editing, attention to detail. Part 2 will be a must-watch!

[DocBees-gl]

A month ago I started my own retro 2d first person raytracing game engine, using your two year old raytracing tutorial as a springboard, but figuring everything out on my own as best I can. I'm very excited to see you're back with more! I don't want to spoil the exploratory process for myself, so it'll probably be many months before I watch this video... but I can already tell from skimming that it's really good!

[arciks]

0:22 decino has alot to say about Doom's engine. And he's yet to run out of steam or yellow backgrounds.

[hhhsp]

You know it really helps when you have unexplained functionality and magic constants in your code tutorial. Very cool.

[paherbst]

This is just the video I've been looking for for years.

[MBBGun]

Im playing it on half speed and frequently pausing. Simple and complicated at the same time, surely truly fascinating. Very cool video!

[joeroeinski]

YOU are a legend sir, keep up with these impressive tutorials. You are clearly knowledgeable and capable of explaining complex concepts in a simple way that everyone can understand

[jumbledfox]

A NEW 3DSAGE VIDEO!!! If only i got the darn notification

[jimlkosmo]

This is the most interesting tutorial i've seen on youtube for the last 10 years. Your explanation is clear and well organized. The only thing i would suggest is, while you are explaining the geometrical logic behind the pixel rendering functions on the program, it would be nicer if you could in parallel show on the screen a small graphic with the vectors so we can follow your thought on real time.
This is great man, thank you for your videos!

[tomasburian]

I'm a lowly JavaScript programmer and yet I still love watching these videos. Makes you wonder what kind of genius a guy must be to come up with this. It's like a whole new level of existence.

[avramitra]

This is the kind of content youtube is for. You sir have earned my subscription. I'm glad to find you

[Saw-qvbl]

Your videos have inspired me to change to OpenGL

[BenColemanUK]

Please continue this series, really great to see this content and the effort you've put in. So little information out there on building a Doom like renderer from scratch like this. Lots for ray casters, but not sector and wall type engines like this