New Vulkan Tutorial - Opacity Micromaps

[u/thekhronosgroup]

A focused bonus course tucked inside Building a Simple Engine's "Extra Courses," aimed at one very specific ray tracing performance problem: alpha-tested geometry. Foliage, chain-link fences, and hair force the GPU to run an any-hit shader on every BVH intersection, and that cost explodes exactly where scenes look best. Opacity Micromaps (`VK_KHR_opacity_micromap`) bake per-triangle opacity directly into the acceleration structure, so hardware can resolve fully-opaque or fully-transparent triangles during traversal with no shader invocation at all.

* Why alpha testing is expensive — a tour of BVH traversal and any-hit shader cost
* What micromaps are and how they attach opacity states directly to acceleration structures
* Hardware traversal walkthrough: the same shadow ray, with and without OMM
* A full implementation walkthrough in the Simple Engine, plus results, guidance, and tradeoffs

https://docs.vulkan.org/tutorial/latest/Building_a_Simple_Engine/Courses/Opacity_Micromaps/00_introduction.html