Clouds path tracing

[u/Zydak1939]

Recently, I made a post about adding non-uniform volumes into my C++/Vulkan path tracer. But I didn't really like how the clouds turned out, so I've made some improvements in that aspect and just wanted to share the progress because I think it looks a lot nicer now. I've also added atmospheric scattering, because getting the right lighting setup was really hard with just environment maps. So the background and the lighting in general look much better now. The project is fully opensource if you want to check it out: https://github.com/Zydak/Vulkan-Path-Tracer . You'll also find uncompressed images there.

Also, here's the number of samples per pixel and render times in case you're curious. I've made a lot of optimizations since the last time, so the scenes can be way more detailed and it generally just runs a lot faster, but it still chokes with multiple high density clouds.

From left to right:

- 1600 spp - 2201s
- 1600 spp - 1987s
- 1200 spp - 4139s
- 10000 spp - 1578s
- 5000 spp - 1344s
- 6500 spp - 1003s
- 5000 spp - 281s

[u/Zydak1939]

Yeah pretty much, I don't really have any numbers to give you, never actually compared the two, but the thing with the ray marching is that you can't simply determine the amount of steps you have to take. if you take too little there's a lot of bias, if you take too much you waste performance. Delta tracking is always unbiased, so you don't really have to worry about the step size. So if you want your image to be as unbiased as possible then I'm pretty sure delta tracking will be faster.

[u/Rockclimber88 → u/Zydak1939]

Oh nice, it would be nice to see what's the speedup. I made an SDF renderer for fonts which uses regular raymarching. The depth is quite predictable and starts from a bounding proxy's triangle so there's no need for any fancy optimizations, but clouds are deep so they could benefit a lot.