From 776ed52157cb4db47a26fa96fb05afc68f6847d6 Mon Sep 17 00:00:00 2001
From: Nicolas Silva <nical@fastmail.com>
Date: Tue, 3 Oct 2023 15:24:21 +0200
Subject: [PATCH] Fully support bind group layout deduplication in
 Pipeline::get_bind_group_layout

---
 wgpu-core/src/device/global.rs | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/wgpu-core/src/device/global.rs b/wgpu-core/src/device/global.rs
index b8817146a2c..e592d113bab 100644
--- a/wgpu-core/src/device/global.rs
+++ b/wgpu-core/src/device/global.rs
@@ -1924,7 +1924,24 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                 None => break binding_model::GetBindGroupLayoutError::InvalidGroupIndex(index),
             };
 
-            bgl_guard[*id].multi_ref_count.inc();
+            let layout = &bgl_guard[*id];
+            layout.multi_ref_count.inc();
+
+            if G::ids_are_generated_in_wgpu() {
+                return (id.0, None);
+            }
+
+            // The ID is provided externally, so we must create a new bind group layout
+            // with the given ID as a duplicate of the existing one.
+            let new_layout = BindGroupLayout {
+                device_id: layout.device_id.clone(),
+                inner: crate::binding_model::BglOrDuplicate::<A>::Duplicate(*id),
+                multi_ref_count: crate::MultiRefCount::new(),
+            };
+
+            let fid = hub.bind_group_layouts.prepare(id_in);
+            let id = fid.assign(new_layout, &mut Token::root());
+
             return (id.0, None);
         };