From 0f37c9922d7886d4a9192161284f321e3b6e450a Mon Sep 17 00:00:00 2001
From: Adam Cosner <160804448+Adam-Cosner@users.noreply.github.com>
Date: Thu, 20 Feb 2025 04:34:39 -0800
Subject: [PATCH] perf: use cached alpha mode instead of calling
 surface.get_capabilities every time the window is redrawn

---
 wgpu/src/window/compositor.rs | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/wgpu/src/window/compositor.rs b/wgpu/src/window/compositor.rs
index 27f9a4da..96370655 100644
--- a/wgpu/src/window/compositor.rs
+++ b/wgpu/src/window/compositor.rs
@@ -397,21 +397,6 @@ impl graphics::Compositor for Compositor {
         width: u32,
         height: u32,
     ) {
-        let caps = surface.get_capabilities(&self.adapter);
-        let alpha_mode = if caps
-            .alpha_modes
-            .contains(&wgpu::CompositeAlphaMode::PostMultiplied)
-        {
-            wgpu::CompositeAlphaMode::PostMultiplied
-        } else if caps
-            .alpha_modes
-            .contains(&wgpu::CompositeAlphaMode::PreMultiplied)
-        {
-            wgpu::CompositeAlphaMode::PreMultiplied
-        } else {
-            wgpu::CompositeAlphaMode::Auto
-        };
-
         surface.configure(
             &self.engine.device,
             &wgpu::SurfaceConfiguration {
@@ -420,7 +405,7 @@ impl graphics::Compositor for Compositor {
                 present_mode: self.settings.present_mode,
                 width,
                 height,
-                alpha_mode,
+                alpha_mode: self.alpha_mode,
                 view_formats: vec![],
                 desired_maximum_frame_latency: 1,
             },