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| title | date | draft | tags | |||
|---|---|---|---|---|---|---|
| Vulkan Deep Dive: Parallax-corrected Reflections and Real-time Image-based Lighting | 2022-10-05 | true |
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You might be wondering why I'm covering reflections and IBLs in this series, as there is tutorials covering these already online.
However, there is two important distinctions in what I'm teaching here:
Parallax-corrected reflections and Real-time Image-based Lighting. In most tutorials, they might cover simple screen space reflections, or if you're lucky - cubemap-based solutions. Most image-based lighting tutorials also limit themselves to existing HDRIs for simplicity, but doing it in real-time or offline when building levels is arguably the more popular option in games, so it's harder to figure out that yourself. As always, let's dig in!
Although I'm covering two topics this time, I did it because they're tangentially related, but I won't be compromising on the details.
Parallax-corrected Reflections
This is something I've been wanting to cover for a long time, because despite still being popular in games, there is very little information out there on how to accomplish this. For clarity, this is an extension of cubemap-based realtime (or offline) reflections using some kind of probe globally or locally. The main difference is for regular reflections, there is no concept of it occupying any real physical space, it's freestanding and doesn't look correct. For really rough or small reflections, it works okay but look at how it looks in a watery environment:
And now with parallax-corrected:
As you can see, it's very convincing at most angles, and doesn't suffer from the downsides of screen-space reflections.
Theory
Implementation
Real-time Image-based Lighting
This tutorial assumes that you already implemented image-based lighting in your engine, as I won't dig into that here (There is much smarter people to tell you how to do that!) This will just cover how to move from existing HDRI to one that is scene-based.
Theory
Note: This isn't really anything to do with any mathematical theory, but it's still a good subsection title ;-)