5 years ago I was 17 and learning to code C/C++ in a coding bootcamp (42). One of the projects was a simple C ray tracer. I really enjoyed working on the project and always loved computer graphics, so I decided to create my own path tracer from scratch, in C++, without using any third-party libraries.
I ended up working on it consistently for over a year, then sporadically when CG excitement hit me again. Recently I polished it and completed some unfinished features and decided to make it public, finally. It's a C++20 Path Tracer with a CPU renderer. It is able to render good-looking images with reasonable performance and sample count.
Btw this was initially coded without AI, but I've used it for the recent clean up and features. This project is a personal favorite of mine, and it can improve a lot, so I'd love to hear your feedback.
Great work, the examples look fantastic. I will say, it's misleading to put "without AI" in the title for you to then comment on your submission that you have in fact used it. While it may only be in a trivial capacity, you've still used it.
> Btw this was initially coded without AI, but I've used it for the recent clean up and features
Then it makes sense to update the submission title. To me it reads as if the project was written completely without the help of AI (which might be a quality badge to some), but it is not 100% true then.
Thanks! I get your point about AI, but I think it's fair to say it's almost 100% AI free. I worked on it for ~15 months, vs 1 week now with AI. Previous results were quite similar
JFYI: Your inverse ray direction calculation is not NaN-safe: if rays are completely axis-parallel in one dimension, so the direction value is 0.0 for that axis, you'll be doing the val / 0.0 which results in a NaN...
Also, as you're using full double/f64-precision all the time, you're leaving a fair bit of performance on the table: transcendentals (sin(), cos(), etc) in particular - can be a lot slower than when using f32, and generally double precision can be special-cased to particular areas of the renderer that need it (curve, sphere intersection, and some situations where volume scattering produces very small distances).
Inverse is still 0.0 technically, but yes, there is a trick you can use with Inf and SIMD to mask them out, so Inf is sometimes used.
However, I'd just condition it for the moment.
so:
invDirX = dirX != 0.0 ? 1.0 / dirX : 0.0;
etc, etc for each dimension.
Obviously doing the != 0.0 comparison is not great, as it suffers from potential issues again (especially if you have denormals), but you can generally get away with it I've found in most cases.
Hey ! Great work , I wanted to try something like this as well to begin my journey into games and computer graphics . I would love to know what resources you used to learn.
The greatest resource I've found on the internet is the Ray Tracing in One Weekend series. (https://raytracing.github.io/) You can start there and go pretty far. Also you can mix random papers you'll find and eventually just testing and experimenting yourself.
Ray tracing is one of those problems that is conceptually so simple, yet continues to take so much mindshare because of all the challenges to implementation.
A C++ ray tracer from scratch was the course project for my computer graphics class in 2016. I enjoyed the exercise immensely. Not nearly as robust as yours of course.
_" Btw this was initially coded without AI, but I've used it for the recent clean up and features. "_
???
Hey HN,
5 years ago I was 17 and learning to code C/C++ in a coding bootcamp (42). One of the projects was a simple C ray tracer. I really enjoyed working on the project and always loved computer graphics, so I decided to create my own path tracer from scratch, in C++, without using any third-party libraries.
I ended up working on it consistently for over a year, then sporadically when CG excitement hit me again. Recently I polished it and completed some unfinished features and decided to make it public, finally. It's a C++20 Path Tracer with a CPU renderer. It is able to render good-looking images with reasonable performance and sample count.
Btw this was initially coded without AI, but I've used it for the recent clean up and features. This project is a personal favorite of mine, and it can improve a lot, so I'd love to hear your feedback.
Great work, the examples look fantastic. I will say, it's misleading to put "without AI" in the title for you to then comment on your submission that you have in fact used it. While it may only be in a trivial capacity, you've still used it.
I get your point. I consider it fair with the disclaimer because the "manual" version was very similar to current but missing some love
> Btw this was initially coded without AI, but I've used it for the recent clean up and features
Then it makes sense to update the submission title. To me it reads as if the project was written completely without the help of AI (which might be a quality badge to some), but it is not 100% true then.
Anyhow, cool project ;)
Thanks! I get your point about AI, but I think it's fair to say it's almost 100% AI free. I worked on it for ~15 months, vs 1 week now with AI. Previous results were quite similar
> think it's fair to say it's almost 100% AI free.
So write "almost without AI" in the title, then!
JFYI: Your inverse ray direction calculation is not NaN-safe: if rays are completely axis-parallel in one dimension, so the direction value is 0.0 for that axis, you'll be doing the val / 0.0 which results in a NaN...
Also, as you're using full double/f64-precision all the time, you're leaving a fair bit of performance on the table: transcendentals (sin(), cos(), etc) in particular - can be a lot slower than when using f32, and generally double precision can be special-cased to particular areas of the renderer that need it (curve, sphere intersection, and some situations where volume scattering produces very small distances).
What's the proper way to handle a zero in the direction vector when calculating the reciprocal direction? Should it evaluate to infinity?
Inverse is still 0.0 technically, but yes, there is a trick you can use with Inf and SIMD to mask them out, so Inf is sometimes used.
However, I'd just condition it for the moment.
so:
invDirX = dirX != 0.0 ? 1.0 / dirX : 0.0; etc, etc for each dimension.
Obviously doing the != 0.0 comparison is not great, as it suffers from potential issues again (especially if you have denormals), but you can generally get away with it I've found in most cases.
Congrats on doing 42 and to have worked and shared your project, very nice results !
Hey ! Great work , I wanted to try something like this as well to begin my journey into games and computer graphics . I would love to know what resources you used to learn.
The greatest resource I've found on the internet is the Ray Tracing in One Weekend series. (https://raytracing.github.io/) You can start there and go pretty far. Also you can mix random papers you'll find and eventually just testing and experimenting yourself.
Congratulations on achieving it.
Congrats ! Results look stunning
Me too, but in TS/WebGPU: https://github.com/ivanjermakov/moonlight
Very fun! Packing data for GPU-side BVH was quite tricky.
Wow, pretty good. Why web?
Ray tracing is one of those problems that is conceptually so simple, yet continues to take so much mindshare because of all the challenges to implementation.
Have you considered rewriting it in Rust? Not for any technical reason (I say it reflexively now)
Not really, but it would be fun. I really like Rust as well
A C++ ray tracer from scratch was the course project for my computer graphics class in 2016. I enjoyed the exercise immensely. Not nearly as robust as yours of course.
I basically was ready to come on and make a snarky comment like this. "I wrote one in the '90s!".
and then I saw the examples, and the feature set. I particularly like the blender-to-Luz export.
It seems great. Good luck to OP.
"Without AI" is the new "Written in Rust", SCNR
for anybody else interested in this undertaking, I recommend this book https://pragprog.com/titles/jbtracer/the-ray-tracer-challeng...
> without AI
Now this is how you catch attention
I expect similar headlines like “I saved on token cost by hiring juniors” to come in soon too
Indeed. Until it turns out not to be true: https://news.ycombinator.com/item?id=48541543
for the love of the game, very refreshing good ol' coding