From 2115ca941be9ca52e70468ec7638d62fd1da6adf Mon Sep 17 00:00:00 2001
From: switch <janosch.graef@gmail.com>
Date: Sun, 7 Dec 2025 23:34:26 +0100
Subject: [PATCH] egui-wgpu: attach stencil buffer (#7702)

---
 crates/eframe/src/web/web_painter_wgpu.rs | 27 +++++++++++++++------
 crates/egui-wgpu/src/winit.rs             | 29 +++++++++++++++++------
 2 files changed, 42 insertions(+), 14 deletions(-)

diff --git a/crates/eframe/src/web/web_painter_wgpu.rs b/crates/eframe/src/web/web_painter_wgpu.rs
index efecd12ee..387366e5a 100644
--- a/crates/eframe/src/web/web_painter_wgpu.rs
+++ b/crates/eframe/src/web/web_painter_wgpu.rs
@@ -243,13 +243,26 @@ impl WebPainter for WebPainterWgpu {
                     depth_stencil_attachment: self.depth_texture_view.as_ref().map(|view| {
                         wgpu::RenderPassDepthStencilAttachment {
                             view,
-                            depth_ops: Some(wgpu::Operations {
-                                load: wgpu::LoadOp::Clear(1.0),
-                                // It is very unlikely that the depth buffer is needed after egui finished rendering
-                                // so no need to store it. (this can improve performance on tiling GPUs like mobile chips or Apple Silicon)
-                                store: wgpu::StoreOp::Discard,
-                            }),
-                            stencil_ops: None,
+                            depth_ops: self
+                                .depth_stencil_format
+                                .is_some_and(|depth_stencil_format| {
+                                    depth_stencil_format.has_depth_aspect()
+                                })
+                                .then_some(wgpu::Operations {
+                                    load: wgpu::LoadOp::Clear(1.0),
+                                    // It is very unlikely that the depth buffer is needed after egui finished rendering
+                                    // so no need to store it. (this can improve performance on tiling GPUs like mobile chips or Apple Silicon)
+                                    store: wgpu::StoreOp::Discard,
+                                }),
+                            stencil_ops: self
+                                .depth_stencil_format
+                                .is_some_and(|depth_stencil_format| {
+                                    depth_stencil_format.has_stencil_aspect()
+                                })
+                                .then_some(wgpu::Operations {
+                                    load: wgpu::LoadOp::Clear(0),
+                                    store: wgpu::StoreOp::Discard,
+                                }),
                         }
                     }),
                     label: Some("egui_render"),
diff --git a/crates/egui-wgpu/src/winit.rs b/crates/egui-wgpu/src/winit.rs
index 3a286cc9e..a35466493 100644
--- a/crates/egui-wgpu/src/winit.rs
+++ b/crates/egui-wgpu/src/winit.rs
@@ -526,13 +526,28 @@ impl Painter {
                 depth_stencil_attachment: self.depth_texture_view.get(&viewport_id).map(|view| {
                     wgpu::RenderPassDepthStencilAttachment {
                         view,
-                        depth_ops: Some(wgpu::Operations {
-                            load: wgpu::LoadOp::Clear(1.0),
-                            // It is very unlikely that the depth buffer is needed after egui finished rendering
-                            // so no need to store it. (this can improve performance on tiling GPUs like mobile chips or Apple Silicon)
-                            store: wgpu::StoreOp::Discard,
-                        }),
-                        stencil_ops: None,
+                        depth_ops: self
+                            .options
+                            .depth_stencil_format
+                            .is_some_and(|depth_stencil_format| {
+                                depth_stencil_format.has_depth_aspect()
+                            })
+                            .then_some(wgpu::Operations {
+                                load: wgpu::LoadOp::Clear(1.0),
+                                // It is very unlikely that the depth buffer is needed after egui finished rendering
+                                // so no need to store it. (this can improve performance on tiling GPUs like mobile chips or Apple Silicon)
+                                store: wgpu::StoreOp::Discard,
+                            }),
+                        stencil_ops: self
+                            .options
+                            .depth_stencil_format
+                            .is_some_and(|depth_stencil_format| {
+                                depth_stencil_format.has_stencil_aspect()
+                            })
+                            .then_some(wgpu::Operations {
+                                load: wgpu::LoadOp::Clear(0),
+                                store: wgpu::StoreOp::Discard,
+                            }),
                     }
                 }),
                 timestamp_writes: None,