Track the dirty status of individual elements in AtomicSparseBufferVec.

crates/bevy_pbr/src/render/mesh.rs

@@ -1641,7 +1641,6 @@ impl Default for MeshCullingDataBuffer {
     fn default() -> Self {
         Self(AtomicSparseBufferVec::new(
             BufferUsages::STORAGE,
-            8,
             Arc::from("mesh culling data buffer"),
         ))
     }

crates/bevy_render/src/batching/gpu_preprocessing.rs

@@ -307,7 +307,6 @@ where
         InstanceInputUniformBuffer {
             buffer: AtomicSparseBufferVec::new(
                 BufferUsages::STORAGE,
-                8,
                 Arc::from("instance input uniform buffer"),
             ),
             free_uniform_indices: vec![],

crates/bevy_render/src/render_resource/sparse_buffer_update.wgsl

@@ -12,10 +12,8 @@
 struct SparseBufferUpdateMetadata {
     // The size of a single element in words.
     element_size: u32,
-    // The total number of pages to be updated.
-    updated_page_count: u32,
-    // The base-2 logarithm of the page size.
-    page_size_log2: u32,
+    // The total number of elements to be updated.
+    updated_element_count: u32,
 };
 
 // The buffer we're copying to.
@@ -34,8 +32,7 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
     // Calculate which word we are. Remember that this shader executes with one
     // thread per word.
     let invocation_index = global_id.x;
-    let total_word_count = (metadata.updated_page_count << metadata.page_size_log2) *
-        metadata.element_size;
+    let total_word_count = metadata.updated_element_count * metadata.element_size;
     if (invocation_index >= total_word_count) {
         return;
     }
@@ -44,16 +41,11 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
     let element_index = invocation_index / metadata.element_size;
     // Calculate which word *within* that element we're looking at.
     let word_index = invocation_index % metadata.element_size;
-    // Calculate which page we're copying.
-    let update_index = element_index >> metadata.page_size_log2;
-    // Determine which element we're copying within that page.
-    let element_index_in_page = element_index & ((1u << metadata.page_size_log2) - 1u);
 
-    // Look up our destination page.
-    let page_index = indices[update_index];
+    // Look up our destination element.
+    let dest_element_index = indices[element_index];
     // Calculate where we should write our word.
-    let dest_index = ((page_index << metadata.page_size_log2) + element_index_in_page) *
-        metadata.element_size + word_index;
+    let dest_index = dest_element_index * metadata.element_size + word_index;
     if (dest_index >= arrayLength(&dest_buffer)) {
         return;
     }