From 6ac8647585c40c28c6fd1b96daff34c430ca7c9d Mon Sep 17 00:00:00 2001
From: Marijn Suijten <marijns95@gmail.com>
Date: Wed, 25 Mar 2026 17:11:20 +0100
Subject: [PATCH] extensions/khr/acceleration_structure: Make some arguments
 optional for `VK_KHR_opacity_micromap`

The new KHR Opacity Micromap extension leverages existing
`vk::AccelerationStructureKHR` objects and related building functions
(as opposed to defining bespoke types and commands in the EXT), but
makes some input arguments to the existing Acceleration Structure
commands optional.  These need to be adjusted in our high-level wrapper
to accommodate for these requirements:

- `max_primitive_counts` in `get_acceleration_structure_build_sizes_khr()`;
- `build_range_infos` in `cmd_build_acceleration_structures()`.

Note that `build_range_infos` in `build_acceleration_structures()` is
not affected, because Opacity Micromaps are limited to device-builds.

See the VUID changes in
https://github.com/KhronosGroup/Vulkan-Headers/commit/0e9de566b7d4051c5cc1b762e242c46565956bdf
for more details.
---
 Changelog.md                                  |  3 ++
 .../extensions/khr/acceleration_structure.rs  | 28 ++++++++++++-------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index f2a48bda2..fb63cd630 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -47,6 +47,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   This trait must be imported in scope (`use ash::vk::TaggedStructure as _;`) to use the `push()` and `extend()` methods.
 - Renamed all extension `::new()` constructors to `::load()`, signifying they're only loading function pointers. (#1021)
 - Replace `specs/1.3-extensions` registry links with new `refpages/latest` documentation links
+- `extensions::khr::acceleration_structure` now takes `Option`al references in the following arguments (#1041):
+  - `max_primitive_counts` in `get_acceleration_structure_build_sizes_khr()`;
+  - `build_range_infos` in `cmd_build_acceleration_structures()`.
 
 ### Removed
 
diff --git a/ash/src/extensions/khr/acceleration_structure.rs b/ash/src/extensions/khr/acceleration_structure.rs
index 4d8c30629..af8908b35 100644
--- a/ash/src/extensions/khr/acceleration_structure.rs
+++ b/ash/src/extensions/khr/acceleration_structure.rs
@@ -4,7 +4,7 @@ use crate::vk;
 use crate::RawPtr;
 use crate::VkResult;
 use alloc::vec::Vec;
-use core::mem;
+use core::{mem, ptr};
 
 impl crate::khr::acceleration_structure::Device {
     /// <https://docs.vulkan.org/refpages/latest/refpages/source/vkCreateAccelerationStructureKHR.html>
@@ -46,7 +46,7 @@ impl crate::khr::acceleration_structure::Device {
         &self,
         command_buffer: vk::CommandBuffer,
         infos: &[vk::AccelerationStructureBuildGeometryInfoKHR<'_>],
-        build_range_infos: &[&[vk::AccelerationStructureBuildRangeInfoKHR]],
+        build_range_infos: &[Option<&[vk::AccelerationStructureBuildRangeInfoKHR]>],
     ) {
         assert_eq!(infos.len(), build_range_infos.len());
 
@@ -54,8 +54,13 @@ impl crate::khr::acceleration_structure::Device {
             .iter()
             .zip(infos.iter())
             .map(|(range_info, info)| {
-                assert_eq!(range_info.len(), info.geometry_count as usize);
-                range_info.as_ptr()
+                if let Some(range_info) = range_info {
+                    assert_eq!(range_info.len(), info.geometry_count as usize);
+                    range_info.as_ptr()
+                } else {
+                    // Must be NULL for at least VUID-vkCmdBuildAccelerationStructuresKHR-ppBuildRangeInfos-11544
+                    ptr::null()
+                }
             })
             .collect::<Vec<_>>();
 
@@ -262,19 +267,22 @@ impl crate::khr::acceleration_structure::Device {
         &self,
         build_type: vk::AccelerationStructureBuildTypeKHR,
         build_info: &vk::AccelerationStructureBuildGeometryInfoKHR<'_>,
-        max_primitive_counts: &[u32],
+        max_primitive_counts: Option<&[u32]>,
         size_info: &mut vk::AccelerationStructureBuildSizesInfoKHR<'_>,
     ) {
-        assert_eq!(
-            max_primitive_counts.len(),
-            build_info.geometry_count as usize
-        );
+        let max_primitive_counts = if let Some(c) = max_primitive_counts {
+            assert_eq!(c.len(), build_info.geometry_count as usize);
+            c.as_ptr()
+        } else {
+            // Must be NULL for at least VUID-vkGetAccelerationStructureBuildSizesKHR-pMaxPrimitiveCounts-11613
+            ptr::null()
+        };
 
         (self.fp.get_acceleration_structure_build_sizes_khr)(
             self.handle,
             build_type,
             build_info,
-            max_primitive_counts.as_ptr(),
+            max_primitive_counts,
             size_info,
         )
     }