From 6c7c6fb99954210c3623b6062b5cfea1b5ba7cf0 Mon Sep 17 00:00:00 2001
From: Imbris <2002109+Imberflur@users.noreply.github.com>
Date: Sat, 20 Jan 2024 22:26:54 -0500
Subject: [PATCH] Make sure to unset current context in wgl
 Surface::configure/present (#5087)

---
 CHANGELOG.md             |  6 ++++++
 wgpu-hal/src/gles/egl.rs |  1 +
 wgpu-hal/src/gles/wgl.rs | 41 +++++++++++++++++++++++-----------------
 3 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9bfea9f35..18a9a81d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,6 +61,12 @@ Bottom level categories:
         - `tan`
         - `tanh`
 
+### Bug Fixes
+
+#### WGL
+
+- In Surface::configure and Surface::present, fix the current GL context not being unset when releasing the lock that guards access to making the context current. This was causing other threads to panic when trying to make the context current. By @Imberflur in [#5087](https://github.com/gfx-rs/wgpu/pull/5087).
+
 ## v0.19.0 (2024-01-17)
 
 This release includes:
diff --git a/wgpu-hal/src/gles/egl.rs b/wgpu-hal/src/gles/egl.rs
index ef0ff4b6f..aa985d812 100644
--- a/wgpu-hal/src/gles/egl.rs
+++ b/wgpu-hal/src/gles/egl.rs
@@ -1092,6 +1092,7 @@ impl Surface {
             .map_err(|e| {
                 log::error!("swap_buffers failed: {}", e);
                 crate::SurfaceError::Lost
+                // TODO: should we unset the current context here?
             })?;
         self.egl
             .instance
diff --git a/wgpu-hal/src/gles/wgl.rs b/wgpu-hal/src/gles/wgl.rs
index a09a50330..dbe821850 100644
--- a/wgpu-hal/src/gles/wgl.rs
+++ b/wgpu-hal/src/gles/wgl.rs
@@ -77,6 +77,24 @@ impl AdapterContext {
 
         AdapterContextLock { inner }
     }
+
+    /// Obtain a lock to the WGL context and get handle to the [`glow::Context`] that can be used to
+    /// do rendering.
+    ///
+    /// Unlike [`lock`](Self::lock), this accepts a device to pass to `make_current` and exposes the error
+    /// when `make_current` fails.
+    #[track_caller]
+    fn lock_with_dc(&self, device: HDC) -> Result<AdapterContextLock<'_>, Error> {
+        let inner = self
+            .inner
+            .try_lock_for(Duration::from_secs(CONTEXT_LOCK_TIMEOUT_SECS))
+            .expect("Could not lock adapter context. This is most-likely a deadlock.");
+
+        inner
+            .context
+            .make_current(device)
+            .map(|()| AdapterContextLock { inner })
+    }
 }
 
 /// A guard containing a lock to an [`AdapterContext`]
@@ -603,16 +621,10 @@ impl Surface {
             window: self.window,
         };
 
-        let inner = context.inner.lock();
-
-        if let Err(e) = inner.context.make_current(dc.device) {
+        let gl = context.lock_with_dc(dc.device).map_err(|e| {
             log::error!("unable to make the OpenGL context current for surface: {e}",);
-            return Err(crate::SurfaceError::Other(
-                "unable to make the OpenGL context current for surface",
-            ));
-        }
-
-        let gl = &inner.gl;
+            crate::SurfaceError::Other("unable to make the OpenGL context current for surface")
+        })?;
 
         unsafe { gl.bind_framebuffer(glow::DRAW_FRAMEBUFFER, None) };
         unsafe { gl.bind_framebuffer(glow::READ_FRAMEBUFFER, Some(sc.framebuffer)) };
@@ -693,16 +705,11 @@ impl crate::Surface<super::Api> for Surface {
         }
 
         let format_desc = device.shared.describe_texture_format(config.format);
-        let inner = &device.shared.context.inner.lock();
-
-        if let Err(e) = inner.context.make_current(dc.device) {
+        let gl = &device.shared.context.lock_with_dc(dc.device).map_err(|e| {
             log::error!("unable to make the OpenGL context current for surface: {e}",);
-            return Err(crate::SurfaceError::Other(
-                "unable to make the OpenGL context current for surface",
-            ));
-        }
+            crate::SurfaceError::Other("unable to make the OpenGL context current for surface")
+        })?;
 
-        let gl = &inner.gl;
         let renderbuffer = unsafe { gl.create_renderbuffer() }.map_err(|error| {
             log::error!("Internal swapchain renderbuffer creation failed: {error}");
             crate::DeviceError::OutOfMemory