From 9f34acd5671987558038ba0abeb24c69220bd581 Mon Sep 17 00:00:00 2001
From: teoxoy <28601907+teoxoy@users.noreply.github.com>
Date: Wed, 3 Jul 2024 13:28:16 +0200
Subject: [PATCH] [wgpu-hal] return `None` in `Adapter.surface_capabilities()`
 if the `Surface` and the `Adapter` don't share the same WebGL2 context

---
 CHANGELOG.md                 |  3 +++
 wgpu-hal/src/gles/adapter.rs |  5 +++++
 wgpu-hal/src/gles/web.rs     | 14 ++++++++++----
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3546f8e4a3..526f6f99c1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -134,6 +134,9 @@ By @atlv24 in [#5383](https://github.com/gfx-rs/wgpu/pull/5383)
 When targeting WebGL2, it has always been the case that a surface had to be created before calling `request_adapter()`.
 We now make this requirement explicit.
 
+Validation was also added to prevent configuring the surface with a device that doesn't share the same underlying
+WebGL2 context since this has never worked.
+
 Calling `enumerate_adapters()` when targeting WebGPU used to return an empty `Vec` and since we now require users
 to pass a compatible surface when targeting WebGL2, having `enumerate_adapters()` doesn't make sense.
 
diff --git a/wgpu-hal/src/gles/adapter.rs b/wgpu-hal/src/gles/adapter.rs
index 9a41dfe113..933c36dc82 100644
--- a/wgpu-hal/src/gles/adapter.rs
+++ b/wgpu-hal/src/gles/adapter.rs
@@ -1151,6 +1151,11 @@ impl crate::Adapter for super::Adapter {
         &self,
         surface: &super::Surface,
     ) -> Option<crate::SurfaceCapabilities> {
+        #[cfg(webgl)]
+        if self.shared.context.webgl2_context != surface.webgl2_context {
+            return None;
+        }
+
         if surface.presentable {
             let mut formats = vec![
                 wgt::TextureFormat::Rgba8Unorm,
diff --git a/wgpu-hal/src/gles/web.rs b/wgpu-hal/src/gles/web.rs
index a36710f648..a6c79721b4 100644
--- a/wgpu-hal/src/gles/web.rs
+++ b/wgpu-hal/src/gles/web.rs
@@ -8,6 +8,7 @@ use super::TextureFormatDesc;
 /// with the `AdapterContext` API from the EGL implementation.
 pub struct AdapterContext {
     pub glow_context: glow::Context,
+    pub webgl2_context: web_sys::WebGl2RenderingContext,
 }
 
 impl AdapterContext {
@@ -124,9 +125,14 @@ impl crate::Instance for Instance {
         if let Some(surface_hint) = surface_hint {
             let gl = glow::Context::from_webgl2_context(surface_hint.webgl2_context.clone());
 
-            unsafe { super::Adapter::expose(AdapterContext { glow_context: gl }) }
-                .into_iter()
-                .collect()
+            unsafe {
+                super::Adapter::expose(AdapterContext {
+                    glow_context: gl,
+                    webgl2_context: surface_hint.webgl2_context.clone(),
+                })
+            }
+            .into_iter()
+            .collect()
         } else {
             Vec::new()
         }
@@ -172,7 +178,7 @@ impl crate::Instance for Instance {
 #[derive(Debug)]
 pub struct Surface {
     canvas: Canvas,
-    webgl2_context: web_sys::WebGl2RenderingContext,
+    pub(super) webgl2_context: web_sys::WebGl2RenderingContext,
     pub(super) swapchain: RwLock<Option<Swapchain>>,
     texture: Mutex<Option<glow::Texture>>,
     pub(super) presentable: bool,