From 421190935f58f2dff0761c588494cb8ce788a27d Mon Sep 17 00:00:00 2001
From: Jack Lavigne <jacklavigne00@gmail.com>
Date: Fri, 17 Apr 2026 18:29:48 +0200
Subject: [PATCH 1/3] hal/gles: add Adapter::new_external() for WebGL2

Mirrors the existing Adapter::new_external in gles/egl.rs and
gles/wgl.rs for importing an externally-created WebGL2 rendering
context. The caller retains ownership of the canvas and the context;
no Surface is created.
---
 wgpu-hal/src/gles/web.rs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/wgpu-hal/src/gles/web.rs b/wgpu-hal/src/gles/web.rs
index 8e404d6b50a..04f49fc384a 100644
--- a/wgpu-hal/src/gles/web.rs
+++ b/wgpu-hal/src/gles/web.rs
@@ -179,6 +179,33 @@ impl crate::Instance for Instance {
     }
 }
 
+impl super::Adapter {
+    /// Creates a new external adapter from an existing WebGL2 rendering context.
+    ///
+    /// # Safety
+    ///
+    /// - The underlying WebGL2 context must be valid (not lost).
+    /// - The underlying WebGL2 context must be valid when interfacing with any objects returned by
+    ///   wgpu-hal from this adapter.
+    /// - The underlying WebGL2 context must be valid when dropping this adapter and when
+    ///   dropping any objects returned from this adapter.
+    pub unsafe fn new_external(
+        webgl2_context: web_sys::WebGl2RenderingContext,
+        options: wgt::GlBackendOptions,
+    ) -> Option<crate::ExposedAdapter<super::Api>> {
+        let glow_context = glow::Context::from_webgl2_context(webgl2_context.clone());
+        unsafe {
+            Self::expose(
+                AdapterContext {
+                    glow_context,
+                    webgl2_context,
+                },
+                options,
+            )
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct Surface {
     canvas: Canvas,

From 7442f3079163b9e543808a69e571d4df9b8a60e7 Mon Sep 17 00:00:00 2001
From: Jack Lavigne <jacklavigne00@gmail.com>
Date: Fri, 17 Apr 2026 18:39:03 +0200
Subject: [PATCH 2/3] CHANGELOG: add entry for WebGL2 Adapter::new_external
 (#9438)

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 529a5def093..7433f217d77 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -82,6 +82,7 @@ By @teoxoy in [#9351](https://github.com/gfx-rs/wgpu/pull/9351).
 #### GLES
 
 - Added support for GLSL passthrough. By @inner-daemons in [#9064](https://github.com/gfx-rs/wgpu/pull/9064).
+- Implement `Adapter::new_external()` for WebGL2 (just like EGL/WGL) to import an external WebGL2 rendering context. By @pepperoni505 in [#9438](https://github.com/gfx-rs/wgpu/pull/9438).
 
 #### DX12
 

From 1c2d0f0ffe2e1fadfa55e24f272ae3d2f8e6d8e3 Mon Sep 17 00:00:00 2001
From: Jack Lavigne <jacklavigne00@gmail.com>
Date: Sat, 18 Apr 2026 01:19:11 +0200
Subject: [PATCH 3/3] hal/gles: expose imported context back through
 Adapter/Device

Pair with Adapter::new_external: embedders that bring their own
WebGL2 context need a way to reach it back for interop. Add
Adapter::adapter_context() and Device::context(), both returning
the AdapterContext so callers can drive raw-GL work on the shared
glow::Context or web_sys::WebGl2RenderingContext.
---
 CHANGELOG.md             |  2 +-
 wgpu-hal/src/gles/web.rs | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7433f217d77..cf206a7e850 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -82,7 +82,7 @@ By @teoxoy in [#9351](https://github.com/gfx-rs/wgpu/pull/9351).
 #### GLES
 
 - Added support for GLSL passthrough. By @inner-daemons in [#9064](https://github.com/gfx-rs/wgpu/pull/9064).
-- Implement `Adapter::new_external()` for WebGL2 (just like EGL/WGL) to import an external WebGL2 rendering context. By @pepperoni505 in [#9438](https://github.com/gfx-rs/wgpu/pull/9438).
+- Implement `Adapter::new_external()` for WebGL2 (just like EGL/WGL) to import an external WebGL2 rendering context, and expose the imported context back through `Adapter::adapter_context()` / `Device::context()`. By @pepperoni505 in [#9438](https://github.com/gfx-rs/wgpu/pull/9438).
 
 #### DX12
 
diff --git a/wgpu-hal/src/gles/web.rs b/wgpu-hal/src/gles/web.rs
index 04f49fc384a..c9c65a04bda 100644
--- a/wgpu-hal/src/gles/web.rs
+++ b/wgpu-hal/src/gles/web.rs
@@ -204,6 +204,17 @@ impl super::Adapter {
             )
         }
     }
+
+    pub fn adapter_context(&self) -> &AdapterContext {
+        &self.shared.context
+    }
+}
+
+impl super::Device {
+    /// Returns the underlying WebGL2 `AdapterContext`.
+    pub fn context(&self) -> &AdapterContext {
+        &self.shared.context
+    }
 }
 
 #[derive(Debug)]