Ban Dynamic Offsets and Binding Arrays in the Same Bind Group

CHANGELOG.md

@@ -56,6 +56,7 @@ a soundness issue, the intent is to move an error from runtime to compile time.
 ### Bindless (`binding_array`) Grew More Capabilities
 
 - DX12 now supports `PARTIALLY_BOUND_BINDING_ARRAY` on Resource Binding Tier 3 Hardware. This is most D3D12 hardware [D3D12 Feature Table] for more information on what hardware supports this feature. By @cwfitzgerald in [#6734](https://github.com/gfx-rs/wgpu/pull/6734).
+- Buffer Dynamic Offsets and Binding Arrays may not be used in the same bind group. By @cwfitzgerald in [#6811](https://github.com/gfx-rs/wgpu/pull/6811)
 
 [D3D12 Feature Table]: https://d3d12infodb.boolka.dev/FeatureTable.html
 

wgpu-core/src/binding_model.rs

@@ -66,6 +66,8 @@ pub enum CreateBindGroupLayoutError {
     },
     #[error(transparent)]
     TooManyBindings(BindingTypeMaxCountError),
+    #[error("Bind groups may not contain both a binding array and a dynamically offset array")]
+    ContainsBothBindingArrayAndDynamicOffsetArray,
     #[error("Binding index {binding} is greater than the maximum number {maximum}")]
     InvalidBindingIndex { binding: u32, maximum: u32 },
     #[error("Invalid visibility {0:?}")]
@@ -315,6 +317,7 @@ pub(crate) struct BindingTypeMaxCountValidator {
     storage_textures: PerStageBindingTypeCounter,
     uniform_buffers: PerStageBindingTypeCounter,
     acceleration_structures: PerStageBindingTypeCounter,
+    has_bindless_array: bool,
 }
 
 impl BindingTypeMaxCountValidator {
@@ -354,6 +357,9 @@ impl BindingTypeMaxCountValidator {
                 self.acceleration_structures.add(binding.visibility, count);
             }
         }
+        if binding.count.is_some() {
+            self.has_bindless_array = true;
+        }
     }
 
     pub(crate) fn merge(&mut self, other: &Self) {
@@ -405,6 +411,19 @@ impl BindingTypeMaxCountValidator {
         )?;
         Ok(())
     }
+
+    /// Validate that the bind group layout does not contain both a binding array and a dynamic offset array.
+    ///
+    /// This allows us to use `UPDATE_AFTER_BIND` on vulkan for bindless arrays. Vulkan does not allow
+    /// `UPDATE_AFTER_BIND` on dynamic offset arrays. See <https://github.com/gfx-rs/wgpu/issues/6737>
+    pub(crate) fn validate_binding_arrays(&self) -> Result<(), CreateBindGroupLayoutError> {
+        let has_dynamic_offset_array =
+            self.dynamic_uniform_buffers > 0 || self.dynamic_storage_buffers > 0;
+        if self.has_bindless_array && has_dynamic_offset_array {
+            return Err(CreateBindGroupLayoutError::ContainsBothBindingArrayAndDynamicOffsetArray);
+        }
+        Ok(())
+    }
 }
 
 /// Bindable resource and the slot to bind it to.

wgpu-core/src/device/resource.rs

@@ -1896,6 +1896,9 @@ impl Device {
             .validate(&self.limits)
             .map_err(binding_model::CreateBindGroupLayoutError::TooManyBindings)?;
 
+        // Validate that binding arrays don't conflict with dynamic offsets.
+        count_validator.validate_binding_arrays()?;
+
         let bgl = BindGroupLayout {
             raw: ManuallyDrop::new(raw),
             device: self.clone(),

wgpu-types/src/lib.rs

@@ -7011,17 +7011,23 @@ impl BindingType {
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct BindGroupLayoutEntry {
     /// Binding index. Must match shader index and be unique inside a BindGroupLayout. A binding
-    /// of index 1, would be described as `layout(set = 0, binding = 1) uniform` in shaders.
+    /// of index 1, would be described as `@group(0) @binding(1)` in shaders.
     pub binding: u32,
     /// Which shader stages can see this binding.
     pub visibility: ShaderStages,
     /// The type of the binding
     pub ty: BindingType,
-    /// If this value is Some, indicates this entry is an array. Array size must be 1 or greater.
+    /// If the binding is an array of multiple resources. Corresponds to `binding_array<T>` in the shader.
     ///
-    /// If this value is Some and `ty` is `BindingType::Texture`, [`Features::TEXTURE_BINDING_ARRAY`] must be supported.
+    /// When this is `Some` the following validation applies:
+    /// - Size must be of value 1 or greater.
+    /// - When `ty == BindingType::Texture`, [`Features::TEXTURE_BINDING_ARRAY`] must be supported.
+    /// - When `ty == BindingType::Sampler`, [`Features::TEXTURE_BINDING_ARRAY`] must be supported.
+    /// - When `ty == BindingType::Buffer`, [`Features::BUFFER_BINDING_ARRAY`] must be supported.
+    /// - When `ty == BindingType::Buffer` and `ty.ty == BufferBindingType::Storage`, [`Features::STORAGE_RESOURCE_BINDING_ARRAY`] must be supported.
+    /// - When `ty == BindingTYpe::StorageTexture`, [`Features::STORAGE_RESOURCE_BINDING_ARRAY`] must be supported.
+    /// - When any binding in the group is an array, no `BindingType::Buffer` in the group may have `has_dynamic_offset == true`
     ///
-    /// If this value is Some and `ty` is any other variant, bind group creation will fail.
     #[cfg_attr(feature = "serde", serde(default))]
     pub count: Option<NonZeroU32>,
 }