Add multiview limits and tests

CHANGELOG.md

@@ -40,6 +40,33 @@ Bottom level categories:
 
 ## Unreleased
 
+### Major Changes
+
+#### Multiview on all major platforms and support for multiview bitmasks
+
+Multiview has been reworked, adding support for DX12 and Metal, and adding testing and validation to wgpu itself.
+This change also introduces a view bitmask, a new field in `RenderPassDescriptor` that allows a render pass to render multiple to non-adjacent layers. Note that this also influences apps that don't use multiview, as they have to set this field to `None`.
+```diff
+- wgpu::RenderPassDescriptor {
+-     label: None,
+-     color_attachments: &color_attachments,
+-     depth_stencil_attachment: None,
+-     timestamp_writes: None,
+-     occlusion_query_set: None,
+- }
++ wgpu::RenderPassDescriptor {
++     label: None,
++     color_attachments: &color_attachments,
++     depth_stencil_attachment: None,
++     timestamp_writes: None,
++     occlusion_query_set: None,
++     multiview_mask: NonZero::new(3),
++ }
+```
+One other breaking change worth noting is that `@builtin(view_index)` now requires a type of `u32`, where previously it required `i32`.
+
+By @SupaMaggie70Incorporated in [#8206](https://github.com/gfx-rs/wgpu/pull/8206).
+
 ## v27.0.0 (2025-10-01)
 
 ### Major Changes
@@ -161,7 +188,6 @@ by if the `Feature::MULTI_DRAW_INDIRECT_COUNT` feature is available on the devic
 
 By @cwfitzgerald in [#8162](https://github.com/gfx-rs/wgpu/pull/8162).
 
-
 #### `wgpu::PollType::Wait` has now an optional timeout
 
 We removed `wgpu::PollType::WaitForSubmissionIndex` and added fields to `wgpu::PollType::Wait` in order to express timeouts.

benches/benches/wgpu-benchmark/renderpass.rs

@@ -370,6 +370,7 @@ impl RenderpassState {
             occlusion_query_set: None,
             timestamp_writes: None,
             depth_stencil_attachment: None,
+            multiview_mask: None,
         });
 
         let start_idx = pass_number * draws_per_pass;
@@ -417,6 +418,7 @@ impl RenderpassState {
             occlusion_query_set: None,
             timestamp_writes: None,
             depth_stencil_attachment: None,
+            multiview_mask: None,
         });
 
         render_pass.set_pipeline(self.bindless_pipeline.as_ref().unwrap());

deno_webgpu/command_encoder.rs

@@ -2,6 +2,7 @@
 
 use std::borrow::Cow;
 use std::cell::RefCell;
+use std::num::NonZero;
 
 use deno_core::cppgc::Ptr;
 use deno_core::op2;
@@ -142,6 +143,7 @@ impl GPUCommandEncoder {
       occlusion_query_set: descriptor
         .occlusion_query_set
         .map(|query_set| query_set.id),
+      multiview_mask: NonZero::new(descriptor.multiview_mask),
     };
 
     let (render_pass, err) = self

deno_webgpu/render_pass.rs

@@ -460,6 +460,9 @@ pub(crate) struct GPURenderPassDescriptor {
   /*#[webidl(default = 50000000)]
   #[options(enforce_range = true)]
   pub max_draw_count: u64,*/
+  #[webidl(default = 0)]
+  #[options(enforce_range = true)]
+  pub multiview_mask: u32,
 }
 
 #[derive(WebIDL)]

examples/features/src/boids/mod.rs

@@ -276,6 +276,7 @@ impl crate::framework::Example for Example {
             depth_stencil_attachment: None,
             timestamp_writes: None,
             occlusion_query_set: None,
+            multiview_mask: None,
         };
 
         // get command encoder

examples/features/src/bunnymark/mod.rs

@@ -122,6 +122,7 @@ impl Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             rpass.set_pipeline(&self.pipeline);
             rpass.set_bind_group(0, &self.global_group, &[]);

examples/features/src/conservative_raster/mod.rs

@@ -273,6 +273,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.pipeline_triangle_conservative);
@@ -295,6 +296,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.pipeline_upscale);

examples/features/src/cube/mod.rs

@@ -356,6 +356,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             rpass.push_debug_group("Prepare data for draw.");
             rpass.set_pipeline(&self.pipeline);

examples/features/src/hello_triangle/mod.rs

@@ -129,6 +129,7 @@ async fn run(event_loop: EventLoop<()>, window: Window) {
                                     depth_stencil_attachment: None,
                                     timestamp_writes: None,
                                     occlusion_query_set: None,
+                                    multiview_mask: None,
                                 });
                             rpass.set_pipeline(&render_pipeline);
                             rpass.draw(0..3, 0..1);

examples/features/src/hello_windows/mod.rs

@@ -133,6 +133,7 @@ async fn run(event_loop: EventLoop<()>, viewports: Vec<(Arc<Window>, wgpu::Color
                                         depth_stencil_attachment: None,
                                         timestamp_writes: None,
                                         occlusion_query_set: None,
+                                        multiview_mask: None,
                                     });
                             }
 

examples/features/src/mesh_shader/mod.rs

@@ -144,6 +144,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             rpass.push_debug_group("Prepare data for draw.");
             rpass.set_pipeline(&self.pipeline);

examples/features/src/mipmap/mod.rs

@@ -170,6 +170,7 @@ impl Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             if let Some(ref query_sets) = query_sets {
                 rpass.write_timestamp(&query_sets.timestamp, timestamp_query_index_base);
@@ -492,6 +493,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             rpass.set_pipeline(&self.draw_pipeline);
             rpass.set_bind_group(0, &self.bind_group, &[]);

examples/features/src/msaa_line/mod.rs

@@ -307,6 +307,7 @@ impl crate::framework::Example for Example {
                     depth_stencil_attachment: None,
                     timestamp_writes: None,
                     occlusion_query_set: None,
+                    multiview_mask: None,
                 })
                 .execute_bundles(iter::once(&self.bundle));
         }

examples/features/src/multiple_render_targets/mod.rs

@@ -182,6 +182,7 @@ impl MultiTargetRenderer {
             depth_stencil_attachment: None,
             timestamp_writes: None,
             occlusion_query_set: None,
+            multiview_mask: None,
         });
         rpass.set_pipeline(&self.pipeline);
         rpass.set_bind_group(0, &self.bindgroup, &[]);
@@ -339,6 +340,7 @@ impl TargetRenderer {
             depth_stencil_attachment: None,
             timestamp_writes: None,
             occlusion_query_set: None,
+            multiview_mask: None,
         });
         rpass.set_pipeline(&self.pipeline);
         rpass.set_bind_group(0, &self.bindgroup_left, &[]);

examples/features/src/ray_cube_compute/mod.rs

@@ -469,6 +469,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.blit_pipeline);

examples/features/src/ray_cube_fragment/mod.rs

@@ -355,6 +355,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.pipeline);

examples/features/src/ray_cube_normals/mod.rs

@@ -455,6 +455,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.blit_pipeline);

examples/features/src/ray_scene/mod.rs

@@ -535,6 +535,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.pipeline);

examples/features/src/ray_shadows/mod.rs

@@ -348,6 +348,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.pipeline);

examples/features/src/ray_traced_triangle/mod.rs

@@ -414,6 +414,7 @@ impl crate::framework::Example for Example {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.blit_pipeline);

examples/features/src/render_to_texture/mod.rs

@@ -95,6 +95,7 @@ async fn run(_path: Option<String>) {
             depth_stencil_attachment: None,
             occlusion_query_set: None,
             timestamp_writes: None,
+            multiview_mask: None,
         });
         render_pass.set_pipeline(&pipeline);
         render_pass.draw(0..3, 0..1);

examples/features/src/shadow/mod.rs

@@ -771,6 +771,7 @@ impl crate::framework::Example for Example {
                     }),
                     timestamp_writes: None,
                     occlusion_query_set: None,
+                    multiview_mask: None,
                 });
                 pass.set_pipeline(&self.shadow_pass.pipeline);
                 pass.set_bind_group(0, &self.shadow_pass.bind_group, &[]);
@@ -816,6 +817,7 @@ impl crate::framework::Example for Example {
                 }),
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             pass.set_pipeline(&self.forward_pass.pipeline);
             pass.set_bind_group(0, &self.forward_pass.bind_group, &[]);

examples/features/src/skybox/mod.rs

@@ -444,6 +444,7 @@ impl crate::framework::Example for Example {
                 }),
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_bind_group(0, &self.bind_group, &[]);

examples/features/src/srgb_blend/mod.rs

@@ -196,6 +196,7 @@ impl<const SRGB: bool> crate::framework::Example for Example<SRGB> {
                 depth_stencil_attachment: None,
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             rpass.push_debug_group("Prepare data for draw.");
             rpass.set_pipeline(&self.pipeline);

examples/features/src/stencil_triangles/mod.rs

@@ -222,6 +222,7 @@ impl crate::framework::Example for Example {
                 }),
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_stencil_reference(1);

examples/features/src/texture_arrays/mod.rs

@@ -402,6 +402,7 @@ impl crate::framework::Example for Example {
             depth_stencil_attachment: None,
             timestamp_writes: None,
             occlusion_query_set: None,
+            multiview_mask: None,
         });
 
         rpass.set_pipeline(&self.pipeline);

examples/features/src/timestamp_queries/mod.rs

@@ -395,6 +395,7 @@ fn render_pass(
             end_of_pass_write_index: Some(*next_unused_query + 1),
         }),
         occlusion_query_set: None,
+        multiview_mask: None,
     });
     *next_unused_query += 2;
 

examples/features/src/uniform_values/mod.rs

@@ -319,6 +319,7 @@ async fn run(event_loop: EventLoop<()>, window: Arc<Window>) {
                                         depth_stencil_attachment: None,
                                         occlusion_query_set: None,
                                         timestamp_writes: None,
+                                        multiview_mask: None,
                                     });
                                 render_pass.set_pipeline(&wgpu_context_ref.pipeline);
                                 // (9)

examples/features/src/water/mod.rs

@@ -750,6 +750,7 @@ impl crate::framework::Example for Example {
                 }),
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.execute_bundles([&self.terrain_bundle]);
@@ -778,6 +779,7 @@ impl crate::framework::Example for Example {
                 }),
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
             rpass.set_pipeline(&self.terrain_pipeline);
             rpass.set_bind_group(0, &self.terrain_normal_bind_group, &[]);
@@ -805,6 +807,7 @@ impl crate::framework::Example for Example {
                 }),
                 timestamp_writes: None,
                 occlusion_query_set: None,
+                multiview_mask: None,
             });
 
             rpass.set_pipeline(&self.water_pipeline);

examples/standalone/02_hello_window/src/main.rs

@@ -107,6 +107,7 @@ impl State {
             depth_stencil_attachment: None,
             timestamp_writes: None,
             occlusion_query_set: None,
+            multiview_mask: None,
         });
 
         // If you wanted to call any drawing commands, they would go here.

naga/src/back/glsl/mod.rs

@@ -5204,8 +5204,13 @@ const fn glsl_built_in(built_in: crate::BuiltIn, options: VaryingOptions) -> &'s
                 "gl_FragCoord"
             }
         }
-        Bi::ViewIndex if options.targeting_webgl => "int(gl_ViewID_OVR)",
-        Bi::ViewIndex => "gl_ViewIndex",
+        Bi::ViewIndex => {
+            if options.targeting_webgl {
+                "gl_ViewID_OVR"
+            } else {
+                "uint(gl_ViewIndex)"
+            }
+        }
         // vertex
         Bi::BaseInstance => "uint(gl_BaseInstance)",
         Bi::BaseVertex => "uint(gl_BaseVertex)",

naga/src/back/hlsl/conv.rs

@@ -172,6 +172,7 @@ impl crate::BuiltIn {
             // to this field will get replaced with references to `SPECIAL_CBUF_VAR`
             // in `Writer::write_expr`.
             Self::NumWorkGroups => "SV_GroupID",
+            Self::ViewIndex => "SV_ViewID",
             // These builtins map to functions
             Self::SubgroupSize
             | Self::SubgroupInvocationId
@@ -180,7 +181,7 @@ impl crate::BuiltIn {
             Self::BaseInstance | Self::BaseVertex | Self::WorkGroupSize => {
                 return Err(Error::Unimplemented(format!("builtin {self:?}")))
             }
-            Self::PointSize | Self::ViewIndex | Self::PointCoord | Self::DrawID => {
+            Self::PointSize | Self::PointCoord | Self::DrawID => {
                 return Err(Error::Custom(format!("Unsupported builtin {self:?}")))
             }
         })

naga/src/back/hlsl/mod.rs

@@ -650,6 +650,8 @@ pub enum Error {
     ResolveArraySizeError(#[from] proc::ResolveArraySizeError),
     #[error("entry point with stage {0:?} and name '{1}' not found")]
     EntryPointNotFound(ir::ShaderStage, String),
+    #[error("requires shader model {1:?} for reason: {0}")]
+    ShaderModelTooLow(String, ShaderModel),
 }
 
 #[derive(PartialEq, Eq, Hash)]

naga/src/back/hlsl/writer.rs

@@ -569,6 +569,14 @@ impl<'a, W: fmt::Write> super::Writer<'a, W> {
     ) -> BackendResult {
         match *binding {
             Some(crate::Binding::BuiltIn(builtin)) if !is_subgroup_builtin_binding(binding) => {
+                if builtin == crate::BuiltIn::ViewIndex
+                    && self.options.shader_model < ShaderModel::V6_1
+                {
+                    return Err(Error::ShaderModelTooLow(
+                        "used @builtin(view_index) or SV_ViewID".to_string(),
+                        ShaderModel::V6_1,
+                    ));
+                }
                 let builtin_str = builtin.to_hlsl_str()?;
                 write!(self.out, " : {builtin_str}")?;
             }