Expose Pipeline Compilation Zero Initialize Workgroup Memory Option (#16301)

# Objective

- wgpu 0.20 made workgroup vars stop being zero-init by default. this
broke some applications (cough foresight cough) and now we workaround
it. wgpu exposes a compilation option that zero initializes workgroup
memory by default, but bevy does not expose it.

## Solution

- expose the compilation option wgpu gives us

## Testing

- ran examples: 3d_scene, compute_shader_game_of_life, gpu_readback,
lines, specialized_mesh_pipeline. they all work
- confirmed fix for our own problems

---

</details>

## Migration Guide

- add `zero_initialize_workgroup_memory: false,` to
`ComputePipelineDescriptor` or `RenderPipelineDescriptor` structs to
preserve 0.14 functionality, add `zero_initialize_workgroup_memory:
true,` to restore bevy 0.13 functionality.

crates/bevy_core_pipeline/src/auto_exposure/pipeline.rs

@@ -89,6 +89,7 @@ impl SpecializedComputePipeline for AutoExposurePipeline {
                 AutoExposurePass::Average => "compute_average".into(),
             },
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/blit/mod.rs

@@ -98,6 +98,7 @@ impl SpecializedRenderPipeline for BlitPipeline {
                 ..Default::default()
             },
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/bloom/downsampling_pipeline.rs

@@ -127,6 +127,7 @@ impl SpecializedRenderPipeline for BloomDownsamplingPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/bloom/upsampling_pipeline.rs

@@ -124,6 +124,7 @@ impl SpecializedRenderPipeline for BloomUpsamplingPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/contrast_adaptive_sharpening/mod.rs

@@ -233,6 +233,7 @@ impl SpecializedRenderPipeline for CasPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/deferred/copy_lighting_id.rs

@@ -160,6 +160,7 @@ impl FromWorld for CopyDeferredLightingIdPipeline {
                     }),
                     multisample: MultisampleState::default(),
                     push_constant_ranges: vec![],
+                    zero_initialize_workgroup_memory: false,
                 });
 
         Self {

crates/bevy_core_pipeline/src/dof/mod.rs

@@ -806,6 +806,7 @@ impl SpecializedRenderPipeline for DepthOfFieldPipeline {
                 },
                 targets,
             }),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/fxaa/mod.rs

@@ -196,6 +196,7 @@ impl SpecializedRenderPipeline for FxaaPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/motion_blur/pipeline.rs

@@ -141,6 +141,7 @@ impl SpecializedRenderPipeline for MotionBlurPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/oit/resolve/mod.rs

@@ -208,6 +208,7 @@ fn specialize_oit_resolve_pipeline(
         depth_stencil: None,
         multisample: MultisampleState::default(),
         push_constant_ranges: vec![],
+        zero_initialize_workgroup_memory: false,
     }
 }
 

crates/bevy_core_pipeline/src/post_process/mod.rs

@@ -344,6 +344,7 @@ impl SpecializedRenderPipeline for PostProcessingPipeline {
             depth_stencil: None,
             multisample: default(),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/skybox/mod.rs

@@ -233,6 +233,7 @@ impl SpecializedRenderPipeline for SkyboxPipeline {
                     write_mask: ColorWrites::ALL,
                 })],
             }),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/skybox/prepass.rs

@@ -105,6 +105,7 @@ impl SpecializedRenderPipeline for SkyboxPrepassPipeline {
                 entry_point: "fragment".into(),
                 targets: prepass_target_descriptors(key.normal_prepass, true, false),
             }),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/smaa/mod.rs

@@ -512,6 +512,7 @@ impl SpecializedRenderPipeline for SmaaEdgeDetectionPipeline {
                 bias: default(),
             }),
             multisample: MultisampleState::default(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }
@@ -571,6 +572,7 @@ impl SpecializedRenderPipeline for SmaaBlendingWeightCalculationPipeline {
                 bias: default(),
             }),
             multisample: MultisampleState::default(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }
@@ -607,6 +609,7 @@ impl SpecializedRenderPipeline for SmaaNeighborhoodBlendingPipeline {
             primitive: PrimitiveState::default(),
             depth_stencil: None,
             multisample: MultisampleState::default(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/taa/mod.rs

@@ -355,6 +355,7 @@ impl SpecializedRenderPipeline for TaaPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_core_pipeline/src/tonemapping/mod.rs

@@ -307,6 +307,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
             depth_stencil: None,
             multisample: MultisampleState::default(),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_gizmos/src/pipeline_2d.rs

@@ -161,6 +161,7 @@ impl SpecializedRenderPipeline for LineGizmoPipeline {
             },
             label: Some("LineGizmo Pipeline 2D".into()),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }
@@ -261,6 +262,7 @@ impl SpecializedRenderPipeline for LineJointGizmoPipeline {
             },
             label: Some("LineJointGizmo Pipeline 2D".into()),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_gizmos/src/pipeline_3d.rs

@@ -158,6 +158,7 @@ impl SpecializedRenderPipeline for LineGizmoPipeline {
             },
             label: Some("LineGizmo Pipeline".into()),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }
@@ -256,6 +257,7 @@ impl SpecializedRenderPipeline for LineJointGizmoPipeline {
             },
             label: Some("LineJointGizmo Pipeline".into()),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_pbr/src/deferred/mod.rs

@@ -390,6 +390,7 @@ impl SpecializedRenderPipeline for DeferredLightingLayout {
             }),
             multisample: MultisampleState::default(),
             push_constant_ranges: vec![],
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_pbr/src/meshlet/material_pipeline_prepare.rs

@@ -200,6 +200,7 @@ pub fn prepare_material_meshlet_meshes_main_opaque_pass<M: Material>(
                     entry_point: material_fragment.entry_point,
                     targets: material_fragment.targets,
                 }),
+                zero_initialize_workgroup_memory: false,
             };
 
             let material_id = instance_manager.get_material_id(material_id.untyped());
@@ -353,6 +354,7 @@ pub fn prepare_material_meshlet_meshes_prepass<M: Material>(
                     entry_point,
                     targets: material_fragment.targets,
                 }),
+                zero_initialize_workgroup_memory: false,
             };
 
             let material_id = instance_manager.get_material_id(material_id.untyped());

crates/bevy_pbr/src/meshlet/pipelines.rs

@@ -76,6 +76,7 @@ impl FromWorld for MeshletPipelines {
                     shader: MESHLET_FILL_CLUSTER_BUFFERS_SHADER_HANDLE,
                     shader_defs: vec!["MESHLET_FILL_CLUSTER_BUFFERS_PASS".into()],
                     entry_point: "fill_cluster_buffers".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -92,6 +93,7 @@ impl FromWorld for MeshletPipelines {
                     "MESHLET_FIRST_CULLING_PASS".into(),
                 ],
                 entry_point: "cull_clusters".into(),
+                zero_initialize_workgroup_memory: false,
             }),
 
             cull_second: pipeline_cache.queue_compute_pipeline(ComputePipelineDescriptor {
@@ -107,6 +109,7 @@ impl FromWorld for MeshletPipelines {
                     "MESHLET_SECOND_CULLING_PASS".into(),
                 ],
                 entry_point: "cull_clusters".into(),
+                zero_initialize_workgroup_memory: false,
             }),
 
             downsample_depth_first: pipeline_cache.queue_compute_pipeline(
@@ -120,6 +123,7 @@ impl FromWorld for MeshletPipelines {
                     shader: MESHLET_DOWNSAMPLE_DEPTH_SHADER_HANDLE,
                     shader_defs: vec!["MESHLET_VISIBILITY_BUFFER_RASTER_PASS_OUTPUT".into()],
                     entry_point: "downsample_depth_first".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -134,6 +138,7 @@ impl FromWorld for MeshletPipelines {
                     shader: MESHLET_DOWNSAMPLE_DEPTH_SHADER_HANDLE,
                     shader_defs: vec!["MESHLET_VISIBILITY_BUFFER_RASTER_PASS_OUTPUT".into()],
                     entry_point: "downsample_depth_second".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -148,6 +153,7 @@ impl FromWorld for MeshletPipelines {
                     shader: MESHLET_DOWNSAMPLE_DEPTH_SHADER_HANDLE,
                     shader_defs: vec![],
                     entry_point: "downsample_depth_first".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -162,6 +168,7 @@ impl FromWorld for MeshletPipelines {
                     shader: MESHLET_DOWNSAMPLE_DEPTH_SHADER_HANDLE,
                     shader_defs: vec![],
                     entry_point: "downsample_depth_second".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -182,6 +189,7 @@ impl FromWorld for MeshletPipelines {
                         .into(),
                     ],
                     entry_point: "rasterize_cluster".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -203,6 +211,7 @@ impl FromWorld for MeshletPipelines {
                         .into(),
                     ],
                     entry_point: "rasterize_cluster".into(),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -226,6 +235,7 @@ impl FromWorld for MeshletPipelines {
                         .into(),
                     ],
                     entry_point: "rasterize_cluster".into(),
+                    zero_initialize_workgroup_memory: false,
                 }),
 
             visibility_buffer_hardware_raster: pipeline_cache.queue_render_pipeline(
@@ -269,6 +279,7 @@ impl FromWorld for MeshletPipelines {
                             write_mask: ColorWrites::empty(),
                         })],
                     }),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -309,6 +320,7 @@ impl FromWorld for MeshletPipelines {
                             write_mask: ColorWrites::empty(),
                         })],
                     }),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -356,6 +368,7 @@ impl FromWorld for MeshletPipelines {
                             write_mask: ColorWrites::empty(),
                         })],
                     }),
+                    zero_initialize_workgroup_memory: false,
                 }),
 
             resolve_depth: pipeline_cache.queue_render_pipeline(RenderPipelineDescriptor {
@@ -381,6 +394,7 @@ impl FromWorld for MeshletPipelines {
                     entry_point: "resolve_depth".into(),
                     targets: vec![],
                 }),
+                zero_initialize_workgroup_memory: false,
             }),
 
             resolve_depth_shadow_view: pipeline_cache.queue_render_pipeline(
@@ -407,6 +421,7 @@ impl FromWorld for MeshletPipelines {
                         entry_point: "resolve_depth".into(),
                         targets: vec![],
                     }),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -434,6 +449,7 @@ impl FromWorld for MeshletPipelines {
                         entry_point: "resolve_material_depth".into(),
                         targets: vec![],
                     }),
+                    zero_initialize_workgroup_memory: false,
                 },
             ),
 
@@ -448,6 +464,7 @@ impl FromWorld for MeshletPipelines {
                     shader: MESHLET_REMAP_1D_TO_2D_DISPATCH_SHADER_HANDLE,
                     shader_defs: vec![],
                     entry_point: "remap_dispatch".into(),
+                    zero_initialize_workgroup_memory: false,
                 })
             }),
         }

crates/bevy_pbr/src/prepass/mod.rs

@@ -571,6 +571,7 @@ where
             },
             push_constant_ranges: vec![],
             label: Some("prepass_pipeline".into()),
+            zero_initialize_workgroup_memory: false,
         };
 
         // This is a bit risky because it's possible to change something that would

crates/bevy_pbr/src/render/gpu_preprocess.rs

@@ -290,6 +290,7 @@ impl SpecializedComputePipeline for PreprocessPipeline {
             shader: MESH_PREPROCESS_SHADER_HANDLE,
             shader_defs,
             entry_point: "main".into(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_pbr/src/render/mesh.rs

@@ -2020,6 +2020,7 @@ impl SpecializedMeshPipeline for MeshPipeline {
                 alpha_to_coverage_enabled,
             },
             label: Some(label),
+            zero_initialize_workgroup_memory: false,
         })
     }
 }

crates/bevy_pbr/src/ssao/mod.rs

@@ -448,6 +448,7 @@ impl FromWorld for SsaoPipelines {
                 shader: PREPROCESS_DEPTH_SHADER_HANDLE,
                 shader_defs: Vec::new(),
                 entry_point: "preprocess_depth".into(),
+                zero_initialize_workgroup_memory: false,
             });
 
         let spatial_denoise_pipeline =
@@ -461,6 +462,7 @@ impl FromWorld for SsaoPipelines {
                 shader: SPATIAL_DENOISE_SHADER_HANDLE,
                 shader_defs: Vec::new(),
                 entry_point: "spatial_denoise".into(),
+                zero_initialize_workgroup_memory: false,
             });
 
         Self {
@@ -513,6 +515,7 @@ impl SpecializedComputePipeline for SsaoPipelines {
             shader: SSAO_SHADER_HANDLE,
             shader_defs,
             entry_point: "ssao".into(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_pbr/src/ssr/mod.rs

@@ -560,6 +560,7 @@ impl SpecializedRenderPipeline for ScreenSpaceReflectionsPipeline {
             primitive: default(),
             depth_stencil: None,
             multisample: default(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_pbr/src/volumetric_fog/render.rs

@@ -600,6 +600,7 @@ impl SpecializedRenderPipeline for VolumetricFogPipeline {
                     write_mask: ColorWrites::ALL,
                 })],
             }),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_render/src/render_resource/pipeline.rs

@@ -108,6 +108,9 @@ pub struct RenderPipelineDescriptor {
     pub multisample: MultisampleState,
     /// The compiled fragment stage, its entry point, and the color targets.
     pub fragment: Option<FragmentState>,
+    /// Whether to zero-initialize workgroup memory by default. If you're not sure, set this to true.
+    /// If this is false, reading from workgroup variables before writing to them will result in garbage values.
+    pub zero_initialize_workgroup_memory: bool,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]
@@ -147,4 +150,7 @@ pub struct ComputePipelineDescriptor {
     /// The name of the entry point in the compiled shader. There must be a
     /// function with this name in the shader.
     pub entry_point: Cow<'static, str>,
+    /// Whether to zero-initialize workgroup memory by default. If you're not sure, set this to true.
+    /// If this is false, reading from workgroup variables before writing to them will result in garbage values.
+    pub zero_initialize_workgroup_memory: bool,
 }

crates/bevy_render/src/render_resource/pipeline_cache.rs

@@ -669,6 +669,7 @@ impl PipelineCache {
         let device = self.device.clone();
         let shader_cache = self.shader_cache.clone();
         let layout_cache = self.layout_cache.clone();
+
         create_pipeline_task(
             async move {
                 let mut shader_cache = shader_cache.lock().unwrap();
@@ -731,10 +732,10 @@ impl PipelineCache {
                     )
                 });
 
-                // TODO: Expose this somehow
+                // TODO: Expose the rest of this somehow
                 let compilation_options = PipelineCompilationOptions {
-                    constants: &std::collections::HashMap::new(),
+                    constants: &default(),
-                    zero_initialize_workgroup_memory: false,
+                    zero_initialize_workgroup_memory: descriptor.zero_initialize_workgroup_memory,
                 };
 
                 let descriptor = RawRenderPipelineDescriptor {
@@ -779,6 +780,7 @@ impl PipelineCache {
         let device = self.device.clone();
         let shader_cache = self.shader_cache.clone();
         let layout_cache = self.layout_cache.clone();
+
         create_pipeline_task(
             async move {
                 let mut shader_cache = shader_cache.lock().unwrap();
@@ -812,10 +814,11 @@ impl PipelineCache {
                     layout: layout.as_ref().map(|layout| -> &PipelineLayout { layout }),
                     module: &compute_module,
                     entry_point: Some(&descriptor.entry_point),
-                    // TODO: Expose this somehow
+                    // TODO: Expose the rest of this somehow
                     compilation_options: PipelineCompilationOptions {
-                        constants: &std::collections::HashMap::new(),
+                        constants: &default(),
-                        zero_initialize_workgroup_memory: false,
+                        zero_initialize_workgroup_memory: descriptor
+                            .zero_initialize_workgroup_memory,
                     },
                     cache: None,
                 };

crates/bevy_render/src/view/window/screenshot.rs

@@ -496,6 +496,7 @@ impl SpecializedRenderPipeline for ScreenshotToScreenPipeline {
                 })],
             }),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_sprite/src/mesh2d/mesh.rs

@@ -674,6 +674,7 @@ impl SpecializedMeshPipeline for Mesh2dPipeline {
                 alpha_to_coverage_enabled: false,
             },
             label: Some(label.into()),
+            zero_initialize_workgroup_memory: false,
         })
     }
 }

crates/bevy_sprite/src/render/mod.rs

@@ -323,6 +323,7 @@ impl SpecializedRenderPipeline for SpritePipeline {
             },
             label: Some("sprite_pipeline".into()),
             push_constant_ranges: Vec::new(),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_ui/src/render/box_shadow.rs

@@ -206,6 +206,7 @@ impl SpecializedRenderPipeline for BoxShadowPipeline {
                 alpha_to_coverage_enabled: false,
             },
             label: Some("box_shadow_pipeline".into()),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_ui/src/render/pipeline.rs

@@ -121,6 +121,7 @@ impl SpecializedRenderPipeline for UiPipeline {
                 alpha_to_coverage_enabled: false,
             },
             label: Some("ui_pipeline".into()),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

crates/bevy_ui/src/render/ui_material_pipeline.rs

@@ -199,6 +199,7 @@ where
                 alpha_to_coverage_enabled: false,
             },
             label: Some("ui_material_pipeline".into()),
+            zero_initialize_workgroup_memory: false,
         };
         if let Some(vertex_shader) = &self.vertex_shader {
             descriptor.vertex.shader = vertex_shader.clone();

crates/bevy_ui/src/render/ui_texture_slice_pipeline.rs

@@ -219,6 +219,7 @@ impl SpecializedRenderPipeline for UiTextureSlicePipeline {
                 alpha_to_coverage_enabled: false,
             },
             label: Some("ui_texture_slice_pipeline".into()),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

examples/2d/mesh2d_manual.rs

@@ -220,6 +220,7 @@ impl SpecializedRenderPipeline for ColoredMesh2dPipeline {
                 alpha_to_coverage_enabled: false,
             },
             label: Some("colored_mesh2d_pipeline".into()),
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

examples/shader/compute_shader_game_of_life.rs

@@ -179,6 +179,7 @@ impl FromWorld for GameOfLifePipeline {
             shader: shader.clone(),
             shader_defs: vec![],
             entry_point: Cow::from("init"),
+            zero_initialize_workgroup_memory: false,
         });
         let update_pipeline = pipeline_cache.queue_compute_pipeline(ComputePipelineDescriptor {
             label: None,
@@ -187,6 +188,7 @@ impl FromWorld for GameOfLifePipeline {
             shader,
             shader_defs: vec![],
             entry_point: Cow::from("update"),
+            zero_initialize_workgroup_memory: false,
         });
 
         GameOfLifePipeline {

examples/shader/custom_phase_item.rs

@@ -343,6 +343,7 @@ impl SpecializedRenderPipeline for CustomPhasePipeline {
                 mask: !0,
                 alpha_to_coverage_enabled: false,
             },
+            zero_initialize_workgroup_memory: false,
         }
     }
 }

examples/shader/custom_post_processing.rs

@@ -287,6 +287,7 @@ impl FromWorld for PostProcessPipeline {
                 depth_stencil: None,
                 multisample: MultisampleState::default(),
                 push_constant_ranges: vec![],
+                zero_initialize_workgroup_memory: false,
             });
 
         Self {

examples/shader/gpu_readback.rs

@@ -180,6 +180,7 @@ impl FromWorld for ComputePipeline {
             shader: shader.clone(),
             shader_defs: Vec::new(),
             entry_point: "main".into(),
+            zero_initialize_workgroup_memory: false,
         });
         ComputePipeline { layout, pipeline }
     }

examples/shader/specialized_mesh_pipeline.rs

@@ -263,6 +263,7 @@ impl SpecializedMeshPipeline for CustomMeshPipeline {
                 count: mesh_key.msaa_samples(),
                 ..MultisampleState::default()
             },
+            zero_initialize_workgroup_memory: false,
         })
     }
 }