diff --git a/shader/shared/bump.wgsl b/shader/shared/bump.wgsl
index f54203d..e3ec23c 100644
--- a/shader/shared/bump.wgsl
+++ b/shader/shared/bump.wgsl
@@ -6,6 +6,7 @@ let STAGE_TILE_ALLOC: u32 = 0x2u;
 let STAGE_PATH_COARSE: u32 = 0x4u;
 let STAGE_COARSE: u32 = 0x8u;
 
+// This must be kept in sync with the struct in src/render.rs
 struct BumpAllocators {
     // Bitmask of stages that have failed allocation.
     failed: atomic<u32>,