Mesh shaders MSL writer

CHANGELOG.md

@@ -47,12 +47,14 @@ Bottom level categories:
 #### Metal
 
 - Unconditionally enable `Features::CLIP_DISTANCES`. By @ErichDonGubler in [#9270](https://github.com/gfx-rs/wgpu/pull/9270).
+- Added full support for mesh shaders, including in WGSL shaders. By @inner-daemons in [#8739](https://github.com/gfx-rs/wgpu/pull/8739).
 
 ### Changes
 
 #### General
 
 - `Features::CLIP_DISTANCE`, `naga::Capabilities::CLIP_DISTANCE`, and `naga::BuiltIn::ClipDistance` have been renamed to `CLIP_DISTANCES` and `ClipDistances` (viz., pluralized) as appropriate, to match the WebGPU spec. By @ErichDonGubler in [#9267](https://github.com/gfx-rs/wgpu/pull/9267).
+- Added more granular limits for mesh shaders. By @inner-daemons in [#8739](https://github.com/gfx-rs/wgpu/pull/8739).
 
 #### Validation
 

examples/features/src/mesh_shader/mod.rs

@@ -43,17 +43,6 @@ fn compile_hlsl(device: &wgpu::Device, entry: &str, stage_str: &str) -> wgpu::Sh
     }
 }
 
-fn compile_msl(device: &wgpu::Device) -> wgpu::ShaderModule {
-    unsafe {
-        device.create_shader_module_passthrough(wgpu::ShaderModuleDescriptorPassthrough {
-            label: None,
-            msl: Some(std::borrow::Cow::Borrowed(include_str!("shader.metal"))),
-            num_workgroups: (1, 1, 1),
-            ..Default::default()
-        })
-    }
-}
-
 struct Shaders {
     ts: wgpu::ShaderModule,
     ms: wgpu::ShaderModule,
@@ -67,7 +56,7 @@ fn get_shaders(device: &wgpu::Device, backend: wgpu::Backend) -> Shaders {
     // In the case that the platform does support mesh shaders, the dummy
     // shader is used to avoid requiring PASSTHROUGH_SHADERS.
     match backend {
-        wgpu::Backend::Vulkan => {
+        wgpu::Backend::Vulkan | wgpu::Backend::Metal => {
             let compiled = compile_wgsl(device);
             Shaders {
                 ts: compiled.clone(),
@@ -86,17 +75,6 @@ fn get_shaders(device: &wgpu::Device, backend: wgpu::Backend) -> Shaders {
             ms_name: "main",
             fs_name: "main",
         },
-        wgpu::Backend::Metal => {
-            let compiled = compile_msl(device);
-            Shaders {
-                ts: compiled.clone(),
-                ms: compiled.clone(),
-                fs: compiled.clone(),
-                ts_name: "taskShader",
-                ms_name: "meshShader",
-                fs_name: "fragShader",
-            }
-        }
         _ => unreachable!(),
     }
 }

naga-cli/src/bin/naga.rs

@@ -575,6 +575,8 @@ fn run() -> anyhow::Result<()> {
 
     params.spv_out.mesh_shader_primitive_indices_clamp = args.validate_mesh_output;
     params.spv_out.task_dispatch_limits = args.task_limits.0;
+    params.msl.mesh_shader_primitive_indices_clamp = args.validate_mesh_output;
+    params.msl.task_dispatch_limits = args.task_limits.0;
 
     if args.bulk_validate {
         return bulk_validate(&args, &params);

naga/src/back/msl/keywords.rs

@@ -344,7 +344,7 @@ const RESERVED: &[&str] = &[
     // Naga utilities
     "DefaultConstructible",
     // Naga builtin names
-    "__local_invocation_id",
+    "__local_invocation_index",
     super::writer::FREXP_FUNCTION,
     super::writer::MODF_FUNCTION,
     super::writer::ABS_FUNCTION,