Revise partial_bindless release note

_release-content/release-notes/partial_bindless_metal.md

@@ -1,36 +1,41 @@
 ---
-title: Partial Bindless on Metal and Reduced Bind Group Overhead
+title: Partial Bindless and Reduced Bind Group Overhead
 authors: ["@holg"]
 pull_requests: [23436]
 ---
 
-Cross-platform game engines must constantly navigate real differences in platform APIs.
-Bevy's goal is to let users write a single application and ship it everywhere —
-Windows, Mac, Linux, mobile — with confidence that it will just work.
-That's a tough promise to live up to: rendering complex scenes on Mac and iOS was markedly slower.
+In an ideal world, Bevy users could write a single application and ship it everywhere, with every last one of the messy cross-platform differences beautifully abstracted away.
+That can be a bit hard though.
+In this particular case, we found that rendering complex scenes on Mac and iOS was markedly slower than it should have been.
 
+Looking into it, the lack of bindless rendering support was to blame.
 Bindless rendering is how modern engines handle scenes with many different materials efficiently: shaders index into shared pools of textures and buffers rather than rebinding them per draw call.
-Bindless is not just a performance optimization — it's how modern renderers are structured.
 
-Metal (Apple's GPU API) supports texture binding arrays but not buffer binding arrays.
-Bevy required both to enable bindless, which previously excluded Metal entirely — even for materials that never use buffer arrays.
-If you were shipping on Mac or iOS, your game was running on a slower, fundamentally different code path.
+Both Metal (Apple's GPU API) and DX12 (an older Windows API) have partial bindless support:
+they permit texture binding arrays but not buffer binding arrays.
+Historically, Bevy required both to enable bindless, which excluded Metal entirely, even for materials that never use buffer arrays.
 
-Most materials, including `StandardMaterial`, only use `#[data(...)]`, textures, and samplers — they never needed buffer array support.
-Bevy now checks what each material actually needs;
-if it only needs texture arrays, it gets bindless on Metal.
-Materials using `#[uniform(..., binding_array(...))]` still fall back to non-bindless on Metal.
+Most materials, including `StandardMaterial`, do not need buffer array support.
+To ensure those materials take the fast path, Bevy now checks the actual needs of each material.
+If you only need texture arrays, your material can be rendered efficiently across Bevy's desktop platforms.
+If you use `#[uniform(..., binding_array(...))]`, expect unusually poor performance when using Metal or DX12.
 
-Two correctness bugs were fixed in the process.
-The sampler limit check was testing the wrong metric: `max_samplers_per_shader_stage` counts binding slots, but the relevant limit is `max_binding_array_sampler_elements_per_shader_stage`, the array element count — a mismatch that could silently exceed hardware limits.
-Bevy now also skips creating binding array slots for resource types a material doesn't use, staying within Metal's hard 31 argument buffer slot limit and reducing overhead on all platforms.
+We've also fixed two important correctness bugs in the process.
+First, we discovered that the sampler limit check was testing the wrong metric: `max_samplers_per_shader_stage` counts binding slots, but the relevant limit is `max_binding_array_sampler_elements_per_shader_stage`, the array element count (a mismatch that could silently exceed hardware limits).
+Second, Bevy now also skips creating binding array slots for resource types a material doesn't use, staying within Metal's hard 31 argument buffer slot limit and reducing overhead on all platforms.
 
 Benchmarked on Bistro Exterior (698 materials), 5-minute runs:
 
 | GPU                      | Avg FPS improvement | Min FPS improvement | Memory      |
 | ------------------------ | ------------------- | ------------------- | ----------- |
 | Apple M2 Max (Metal)     | +18%                | +77%                | −57 MB RAM  |
 | NVIDIA 5060 Ti           | +84%                | +174%               | Same        |
-| Intel i360P              | +15%                | Same                | Same        |
 | AMD Vega 8 / Ryzen 4800U | Same                | Same                | −88 MB VRAM |
+| Intel i360P              | +15%                | Same                | Same        |
 | Intel Iris XE            | Same                | Same                | Same        |
+
+[Bistro] is a demanding, fairly realistic scene.
+While bindless limitations remain frustrating, especially on Mac where Vulkan isn't an option,
+it's lovely to see those performance gains, and to know that Bevy itself is no longer artificially holding our users back.
+
+[Bistro]: https://developer.nvidia.com/orca/amazon-lumberyard-bistro