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.
ttoinou•2h ago
Congrats ! Results look stunning
shinycode•1h ago
Congrats on doing 42 and to have worked and shared your project, very nice results !
hresvelgr•1h ago
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.
pixelesque•1h ago
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).
deliveryboyman•35m ago
What's the proper way to handle a zero in the direction vector when calculating the reciprocal direction? Should it evaluate to infinity?
pixelesque•23m ago
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.
pjmlp•1h ago
Congratulations on achieving it.
smartmic•1h ago
> 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 ;)
manoji•1h ago
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.
I expect similar headlines like “I saved on token cost by hiring juniors” to come in soon too
eleventen•6m ago
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.
martiano•4h ago
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.
ttoinou•2h ago
shinycode•1h ago
hresvelgr•1h ago
pixelesque•1h ago
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).
deliveryboyman•35m ago
pixelesque•23m ago
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.
pjmlp•1h ago
smartmic•1h ago
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 ;)
manoji•1h ago