From 7b3d4a9edb9de4d82152af60a66a07fc370bfc06 Mon Sep 17 00:00:00 2001
From: Jelle Raaijmakers <jelle@ladybird.org>
Date: Tue, 28 Jan 2025 11:07:42 +0100
Subject: [PATCH] LibWeb: Cache Skia backend context in TraversableNavigable

We just need to create the backend context once and let Skia handle the
context's state.

On my machine, this reduces the load time for https://tweakers.net from
7.5s to 3.5s.
---
 .../LibWeb/HTML/TraversableNavigable.cpp      | 41 +++++++++++--------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/Libraries/LibWeb/HTML/TraversableNavigable.cpp b/Libraries/LibWeb/HTML/TraversableNavigable.cpp
index 6a0cf7f0b22..64ebff28d84 100644
--- a/Libraries/LibWeb/HTML/TraversableNavigable.cpp
+++ b/Libraries/LibWeb/HTML/TraversableNavigable.cpp
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2022, Andreas Kling <andreas@ladybird.org>
+ * Copyright (c) 2025, Jelle Raaijmakers <jelle@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -25,29 +26,35 @@ namespace Web::HTML {
 
 GC_DEFINE_ALLOCATOR(TraversableNavigable);
 
+static RefPtr<Gfx::SkiaBackendContext> g_cached_skia_backend_context;
+
+static RefPtr<Gfx::SkiaBackendContext> get_skia_backend_context()
+{
+    if (!g_cached_skia_backend_context) {
+#ifdef AK_OS_MACOS
+        auto metal_context = Gfx::get_metal_context();
+        g_cached_skia_backend_context = Gfx::SkiaBackendContext::create_metal_context(*metal_context);
+#elif USE_VULKAN
+        auto maybe_vulkan_context = Gfx::create_vulkan_context();
+        if (maybe_vulkan_context.is_error()) {
+            dbgln("Vulkan context creation failed: {}", maybe_vulkan_context.error());
+            return {};
+        }
+
+        auto vulkan_context = maybe_vulkan_context.release_value();
+        g_cached_skia_backend_context = Gfx::SkiaBackendContext::create_vulkan_context(vulkan_context);
+#endif
+    }
+    return g_cached_skia_backend_context;
+}
+
 TraversableNavigable::TraversableNavigable(GC::Ref<Page> page)
     : Navigable(page)
     , m_session_history_traversal_queue(vm().heap().allocate<SessionHistoryTraversalQueue>())
 {
-#ifdef USE_VULKAN
-    auto display_list_player_type = page->client().display_list_player_type();
-    if (display_list_player_type == DisplayListPlayerType::SkiaGPUIfAvailable) {
-        auto maybe_vulkan_context = Gfx::create_vulkan_context();
-        if (!maybe_vulkan_context.is_error()) {
-            auto vulkan_context = maybe_vulkan_context.release_value();
-            m_skia_backend_context = Gfx::SkiaBackendContext::create_vulkan_context(vulkan_context);
-        } else {
-            dbgln("Vulkan context creation failed: {}", maybe_vulkan_context.error());
-        }
-    }
-#endif
-
-#ifdef AK_OS_MACOS
     auto display_list_player_type = page->client().display_list_player_type();
     if (display_list_player_type == DisplayListPlayerType::SkiaGPUIfAvailable)
-        auto metal_context = Gfx::get_metal_context();
-    m_skia_backend_context = Gfx::SkiaBackendContext::create_metal_context(*metal_context);
-#endif
+        m_skia_backend_context = get_skia_backend_context();
 }
 
 TraversableNavigable::~TraversableNavigable() = default;