Adding ray tracing (back) to my game engine [Voxel Devlog #17] 

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I had a dream. That every one of the "I made a voxel engine" youtubers came together to code an open-source voxel engine and put it on github under an open-source license, and it was so awesome and slick and efficient that the open-source community came together and rebuilt minecraft and hundreds of other games/mods on top of it. Then I woke up and I had to go to work :( Great video.

This small niche of voxel engine ytubers is so comfy

Not only have you gotten better on the technical side of things, but you have also improved a lot in video quality! Keep going man, love your stuff!

The data structure you're describing is called an N^3-tree which generalize octrees. Since you use a branching factor of 4, that would be a 4^3 tree. As you noted, it's possible to efficiently traverse this structure thanks to the bitmask trick. A very efficient algorithm for traversal is called hierarchical DDA (digital differential analyser), which is more commonly used for dense voxel grids but can also be applied in a hierarchical fashion on each level. Note that you may use a different branching factor on each level in order to reduce the depth of the structure while still retaining good sparsity. There is a paper describing all of this called "VDB: High-Resolution Sparse Volumes with Dynamic Topology" in case you need a reference. In my own work, I use a 3 level hierarchy where the first level is dense and the following two use a branching factor of 4. Hope this helps :)

Welcome back to raytracing! I’m really excited to see where you take this engine.

DUDE! 10:49 This reminds me of the old "Ace of Spades" game. Basically a voxel fps that could run on anything when I was a kid. I would love a sandbox game or anything really in a retro style like this! Keep going I got really excited while watching this video :D

THC Tree 😅. I've heard it referred to before as a 64-tree

The low-res style is sick! I think it would suit a horror game very well.

GPU memory isn't slow, it's way way faster than standard system memory. GPUs aren't designed though to be programmed like CPUs you need to take into account the architectural differences and leverage the GPUs huge advantages when designing memory structures to be run on them.

Holy crap that church looked amazing

Lower resolution looks perfectly fine. imo it will create better result if used well

Amazing progress, I love your devlogs! :)

Lets go!

Awesome! It's incredible that you had the motivation to re-write all of that.

Nice to see the project coming along! Very excited! Thank you!

great progress, I've been a fan of voxel worlds since I was a wee little child, so it's always a treat seeing some new progress in this arena

Well DonE! I absolutely love the new vid style! Please keep up your good work!

Really beautiful! And the performance is insane 😲

Loved the video! also thanks for linking Gabe's channel that one's new to me

Also known as a multi-layer grid, I have used these a lot. You can actually make it a little more efficient memory wise for spatially by hashing multiple values in the same nodes. The first low resolution grid is sometimes also called a bloom filter. You can use a processor's vector instructions like SIMD, openvc or cuda to skip many empty bits at once.

just started my data structure/algorithms course and seeing why the efficiency can be so important even on personal projects is motivating

Love this! I saw some other comments on further ways to optimize traversal & memory usage, but from now on the common term for the 4^3-tree models should obviously be the THC-tree model 😄

I tried the demo, I was quicker than expected. Good work.

Easily my favourite RU-vidr, another great upload!

I think it is amazing what you were able to achieve with the surface normals. Not using polygons frees you of building the chunks with this geometry to render the voxels. Nice idea, really amazing !

Super awesome! It is pretty funny how many dev log videos start with. “I decided to reprogram it from scratch” 😂 I am also guilty of doing this tho so can’t say much

10k RU-vidrs - "I'll optimize this engine, even with the cost of rewriting 11 thousand lines of code." Multimillion companies hiring hundreds of programmers - "It reaches 48 FPS on RTX 4090, that should be enough!" Thank you for the video, it's very informative. Great job!

That's a very nice acheivment. Congrat

I mean, if you're a programmer in your early 20s and you like CG programming - then you need to make your own voxel engine. I don't make the rules.

The resolution and resource scaling is perfect on this lol. 100% gpu and cpu usage across 32 threads, and 1100fps default window size to 280 at 1440p. Looking forward to seeing how this project progresses, great job on it!

This is so awesome!! The game looks amazing keep going!

First time I've come across your channel. I've always felt voxels are like a computer making graphics like (checks notes) a Post-Impressionist oil painter. The church and village at the end of the vid? Both facinate and excite my brain for reasons I simply can't fathom. Love, love, love voxels and if that's your engine? You've absolutely cracked it visual wise. Subscribed.

Excellent work. I'm happy you went back to ray tracing. It does look much better. I love the idea of using photogrammetry to build out levels. I think this would make a really interesting almost PS1 looking game.

This is amazing, continue your good work

I've always loved voxels, since Ken Silverman's Voxlap engine. I love the destructibility in particular, since polygons can't really do this. I think you have the rare opportunity to push the medium. So if we take the concept of destruction and voxel physics. What other cool things can we do that is only achievable with voxels? What are the limitations with polygons? I really feel like the future of game dev will be in a medium similar to voxels but something like gaussian splatting. Where the engine works with atoms. Maybe it's best to think of voxels as atoms. It's really an exciting area that has been so neglected by developers. You're very lucky to be working in an area that is yet to be fully explored creatively.

that looks amazing!

The low resolution has a really cool old-school feeling to it; you should play around with a CRT post-processing pass, could look awesome with the right resolution settings!

This has to be the most immersive voxel engine I’ve seen so far

real scan environment looks so sick. with a little bit of hand finishing it would be an amazing level generation tool

Very intresting to watch, thank you

Rerwriting is at the heart of gamedev :)

Looks crazy cool!

Oh also wanted to say that I found your channel (which has been great by the way). Because of a random video "You can Parry Nukes" for that V.A. Proxy game. I thought, Man it would be cool if that slash or explosion could slice a mountain in half as it traveled forward. Then I started thinking of Voxel destruction and how Voxel art would be pretty good for showcasing that kind of destruction. (Even that game looks like it be transformed into a Voxel art style. Then ended up down a rabbit hole of Voxel plugins for Unreal then custom Voxel engines and such which led me here.

Beautiful work.

awesome demo!

Imagine Magic Carpet remake with this tech!!!! Destructable castles, volcanos, tremors, everything. :DD

Woooo! He's back at it again with the rewrite! This guy is gonna be the next Notch!

Absolutely love the photoscans!!! Also, i think the formal term for a tree with 8^3 sized nodes is a B+tree, B as in binary, + as in more than two children.

Love your work. Voxel engines have a nostalgic place for me. Games like the original Outcast or Comanche (this dates me) had astonishing visuals for their time. That a voxel engine was possible on 1992 when barely any games were 3D at all is testment to their potential. There's a certain charm and art style to low res combined with a blocky world that is worth exploring. Bonus if that means it can run on a potato or a very old machine. Great potential there.

this looks so good, i find the low resolution version charming

Very cool dude!

Wow, this is so cool!

wow this looks amazing

One of the things I always wanted in AoS was vehicles. Imagine driving around a map in a Jeep, or driving a self-propelled artillery to a strategic high point? I could never figure out how a vechicle would navigate voxel terrain, but this idea of "normals for each voxel" could make it work.

I really like the low res look, especially if you add moody lighting and fog

This is incredible!

The lower resolution + voxel style together looks very nice. Perfect for lower end GPUs as well like you said.

damn dude, this is the coolest stuff in CS in my opinion. Such a good combination of math and algorithms/data structures, to make something that looks so cool, and if it wasn't for job prospects, I'd totally go for it. I'm in second year uni, in cs and physics, and I'm so split in what area I want to go in. I worked on my own shitty, completely entry level 3D rendering/physics engine, and it was so much fun. But the game industry is going through so much layoffs right now, and if I want to work on other physics simulations like robotics or autopilots, it seems like I'd need a masters, which idk if I'd go for. I'm so torn on what I should work on this summer, if I should continue working on my game engine, or get into AI which is probably the more employable path, but doesn't seem as interesting as this. Also from what I hear game devs don't earn as much as other software engineers, but I wouldn't call this type of thing "game dev", more like engine designer, right? does it pay adequately to how much work you have to put in? maybe I care about the pay too much...

Video quality is great!

11:10 Looks even more nostalgic really.

Wait a sec.. i recognize you. I used your fork of cpal for getting audio to work on the web in my game engine. Thanks and keep it up with the rust graphics content!!

Wow, great job! Hope you can also implement reflection and refraction!

11:08 super cute, love it

Duuuuuuuuuuuuuude this is awesome. All these voxel games 😊

I believe the "higher levels" of searching through the voxels is some form of spatial hashing (you "hash" the ray positions to a coarser grid, which is then used to iterate through smaller grids).

I love how the game looks on the IC, maybe even better than on the GTX.

considering how fast these engines are at lower window resolutions, exploring upscaling options similar to DLSS might be a valuable win for lower end hardware. i think the nature of voxel scenes could lend themselves extremely well to certain upscaling techniques (or look ugly idk). would be fun to expiriment

The low resolution gives me 90s vibes in a good way.

That church looks oddly familiar 🤔

just here to say I love the low res look, look like one of those "demake" but with its own style and not just PS1/2 look

The photoscan stuff is the best reminds me of Vagrant Story on PS1, some of the best lo-fi graphics ever made!

Man keep It up! The best voxel engine will be the one that gets published

This looks cool

Incredible! 😮

This video was great

This is nice!

Damn, this is impressive.

Cool video!

Amazing :) What do you think could be done to prevent the low res version from "flickering"? Also, how do you calculate the voxel normal? From what I've seen you color the whole voxel one color instead per voxel face, no?

Your brick tree is similar to cone marching just in grid aligned space, and could also be thought of as a sort of acceleration structure.

Great video! I am curious if you plan on tweaking the shadows and lighting to make it more realistic? I noticed that there is a lot of ambient light being used. Any plans to use a raytracing/phong lighting system in the future?

Fantastic! Is there a game / project in mind for the engine, or are you planning to release the engine itself? Either way, great work and I enjoyed hearing about the more granular GPU challenges and solutions you encountered - thanks for sharing!

very cool video

Wow, that "low resolution" looks very interesting IMO. Idk why, but it reminds me ps1, and it's fascinating that it's all voxels. I think there would be a lot of cases of making use a such style. And it's true pixel-art (without shifting and rotating pixels)

I love this yo

It all looks really good. Will other things, like transparency or volumetrics, be easier with this new method?

Amazing!

I get around 8 fps on integrated graphics in the church which is 8 more than I expected, good work! (laptop defaults to IGPU with chrome)

Ray tracing you say? Oh, i see, that rays bouncing around and making super realistic... wait... it's ray marching

Try and add FSR 3 for lower resolutions on integrated video cards. You might end up gaining quality, even with high-end specs for this specific engine. You can also consider exchanging the language to Zig, as benchmarks show it can be up to almost 10x faster than C.

could you please go into more detail about per voxel normals? either here or in another video?

Fantastic! Why oh why don't we see more retro-style games using voxels? I guess the engine programming is difficult and non-standard, but old games like Outcast and even older games like Ecstatica were fantastic, and the low-rez example in the end of this video reminds me a lot of Ecstatica for example. More! More!

Honestly, the low resolution example at the end looks much more interesting in my opinion. The high resolution shots, especially of the mediterranean cityscape, look sort of uncanny and moreover kind of lifeless. Could be sublime for horror games though I suppose.

Wow! (11:00) a multiplayer map for Gears [ War

I think global illumination could really make your engine look *even* better. I recently learned about an interesting technique for global illumination from a channel called xima. In his voxel engine he is using a cellular-automata based global illumination model that runs in a compute shader(to great effect).

Now I really wanna see it with multiple ray bounces. Deeper shadows would go a long way in bringing out the details.

Incredible

god you're so cool, i hope i'm this good at programming one day

great video.