feat: 透明窗口支持 + 退出确认流程 + ImGui 总开关

用户自主改进批次：
- 透明窗口：GLFW_TRANSPARENT_FRAMEBUFFER + 窗口 opacity 0.5，
  swapchain composite alpha 按能力自适应（Opaque/Pre/PostMultiplied），
  Forward 清屏 alpha=0，tonemap 透传 HDR alpha——物体实体、背景透明
- 退出确认：Window 挂 WindowCloseCallback 发事件，App 侧 OnWindowClose
  置确认标记，OnRenderOverlay 弹 ImGui 确认框后 Close()；
  主循环退出条件改为 m_Running（close 事件驱动）
- ImGui 总开关：` 键切换 ImGuiLayer::SetEnabled，禁用时跳过
  NewFrame/OnRenderOverlay/BuildDrawData 整段
- 帧率控制简化：去掉 LimitFps 开关，非 vsync 时恒按 target 限帧
  （默认 60，可调 ≥24）；m_VSync 默认 false（Mailbox 不限速）
- 清理：Model.cpp const 修正，swapchain 日志带 present mode，
  GPU 遥测暂时注释

验证：0 error 0 warning，composite alpha 实测选 PreMultiplied(0x2)，
present=Mailbox

App/main.cpp

@@ -54,7 +54,7 @@ protected:
 
         m_Ground = scene.CreateEntity("Ground");
         m_Ground.AddComponent<TransformComponent>()
-            .SetPosition(glm::vec3(0.0f, -0.5f, 0.0f))
+                .SetPosition(glm::vec3(0.0f, -4.5f, 0.0f))
                 .Compose();
         m_Ground.AddComponent<MeshRendererComponent>(MeshRendererComponent{ground});
 
@@ -65,9 +65,10 @@ protected:
         camera.camera.SetPosition(glm::vec3(0.0f, 0.0f, 7.0f));
 
         // 背包实体 × 3（悬浮在地面上方）
-        auto size = 10;
-        for (int i = 0; i < size; ++i) {
-            for (int j = 0 ; j < size; j ++)
+        auto size = 1;
+        for (int i = 0; i < size; ++i)
+        {
+            for (int j = 0; j < size; j++)
             {
                 auto e = scene.CreateEntity("Backpack" + std::to_string(i));
 
@@ -85,13 +86,17 @@ protected:
         // 灯光实体（第一个灯 = 阴影光源）
         m_KeyLight = scene.CreateEntity("KeyLight");
         m_KeyLight.AddComponent<LightComponent>(
-            LightComponent{glm::vec3(-0.5f, -0.6f, -0.35f),
-                           glm::vec4(1.0f, 0.95f, 0.9f, 1.0f)});
+            LightComponent{
+                glm::vec3(-0.5f, -0.6f, -0.35f),
+                glm::vec4(1.0f, 0.95f, 0.9f, 1.0f)
+            });
 
         scene.CreateEntity("FillLight")
              .AddComponent<LightComponent>(
-                LightComponent{glm::vec3(0.5f, -0.5f, 0.3f),
-                               glm::vec4(0.3f, 0.5f, 1.0f, 0.8f)});
+                 LightComponent{
+                     glm::vec3(0.5f, -0.5f, 0.3f),
+                     glm::vec4(0.3f, 0.5f, 1.0f, 0.8f)
+                 });
     }
 
     void OnUpdate(f32 deltaTime) override
@@ -103,7 +108,8 @@ protected:
                 .camera.Update(GetWindow(), deltaTime);
 
         // 旋转动画：编辑 Transform 分量后 Compose 重算 world
-        for (size_t i = 0; i < m_Spinners.size(); ++i) {
+        for (size_t i = 0; i < m_Spinners.size(); ++i)
+        {
             auto& t = m_Spinners[i].GetComponent<TransformComponent>();
             t.rotation.y = m_Time * 60.0f + static_cast<f32>(i) * 40.0f;
             t.scale = glm::vec3(0.5f);
@@ -117,18 +123,18 @@ protected:
 
     void OnRenderOverlay() override
     {
-        if (!m_OverlayVisible) return;
-
         ImGui::ShowDemoWindow();
 
         ImGui::Begin("Scene Debug");
 
         // 阴影光源方向：拖动滑条实时看影子变化
-        if (auto* light = m_KeyLight.TryGetComponent<LightComponent>()) {
+        if (auto* light = m_KeyLight.TryGetComponent<LightComponent>())
+        {
             ImGui::Text("Key Light (shadow caster)");
             ImGui::SliderFloat3("direction",
                                 &light->direction.x, -1.0f, 1.0f);
-            if (ImGui::Button("reset")) {
+            if (ImGui::Button("reset"))
+            {
                 light->direction = glm::vec3(-0.5f, -0.6f, -0.35f);
             }
         }
@@ -138,21 +144,25 @@ protected:
         ImGui::Separator();
         ImGui::Text("Tonemap");
         f32 exposure = renderer.GetExposure();
-        if (ImGui::SliderFloat("exposure", &exposure, 0.1f, 4.0f)) {
+        if (ImGui::SliderFloat("exposure", &exposure, 0.1f, 4.0f))
+        {
             renderer.SetExposure(exposure);
         }
         bool aces = renderer.GetUseACES();
-        if (ImGui::Checkbox("ACES", &aces)) {
+        if (ImGui::Checkbox("ACES", &aces))
+        {
             renderer.SetUseACES(aces);
         }
 
         ImGui::Text("Bloom");
         f32 threshold = renderer.GetBloomThreshold();
-        if (ImGui::SliderFloat("threshold", &threshold, 0.0f, 2.0f)) {
+        if (ImGui::SliderFloat("threshold", &threshold, 0.0f, 2.0f))
+        {
             renderer.SetBloomThreshold(threshold);
         }
         f32 strength = renderer.GetBloomStrength();
-        if (ImGui::SliderFloat("strength", &strength, 0.0f, 2.0f)) {
+        if (ImGui::SliderFloat("strength", &strength, 0.0f, 2.0f))
+        {
             renderer.SetBloomStrength(strength);
         }
 
@@ -161,7 +171,8 @@ protected:
         ImGui::Text("GPU Timings");
         const auto& names = renderer.GetPassNames();
         const auto& times = renderer.GetPassGpuMs();
-        for (size_t i = 0; i < names.size() && i < times.size(); ++i) {
+        for (size_t i = 0; i < names.size() && i < times.size(); ++i)
+        {
             ImGui::Text("  %-12s %.3f ms", names[i].c_str(), times[i]);
         }
 
@@ -170,22 +181,22 @@ protected:
         ImGui::Separator();
         ImGui::Text("Frame");
         bool vsync = app.GetVSync();
-        if (ImGui::Checkbox("VSync", &vsync)) {
+        if (ImGui::Checkbox("VSync", &vsync))
+        {
             app.SetVSync(vsync);
-        }
-        bool limit = app.GetLimitFps();
-        if (ImGui::Checkbox("Limit FPS", &limit)) {
-            app.SetLimitFps(limit);
-        }
-        if (limit) {
-            if (vsync) {
-                ImGui::TextDisabled("(vsync 开启时限帧无效)");
-            } else {
-                f32 target = app.GetTargetFps();
-                if (ImGui::SliderFloat("target fps", &target, 24.0f, 360.0f, "%.0f")) {
+            if (!vsync)
+            {
+                const f32 target = app.GetTargetFps();
                 app.SetTargetFps(target);
             }
         }
+        if (!vsync)
+        {
+            f32 target = app.GetTargetFps();
+            if (ImGui::SliderFloat("target fps", &target, 24.0f, 360.0f, "%.0f"))
+            {
+                app.SetTargetFps(target);
+            }
         }
 
         ImGui::Separator();
@@ -194,32 +205,76 @@ protected:
                     static_cast<unsigned long long>(GetFrameCount()));
 
         ImGui::End();
+
+
+        // 自定义重载事件： 重载关闭事件模态框
+        {
+            if (m_ShowQuitConfirm)
+            {
+                ImGui::OpenPopup("Should quit?");
+                m_ShowQuitConfirm = false;
+            }
+
+            ImGui::SetNextWindowPos(
+                ImGui::GetMainViewport()->GetCenter(),
+                ImGuiCond_Appearing, ImVec2(0.5f, 0.5f));
+
+            if (ImGui::BeginPopupModal("Should quit?", nullptr,
+                                       ImGuiWindowFlags_AlwaysAutoResize))
+            {
+                ImGui::TextUnformatted("Quit the application?");
+                ImGui::Separator();
+                if (ImGui::Button("Yes", ImVec2(120, 0)))
+                {
+                    m_QuitConfirmed = true;
+                    ImGui::CloseCurrentPopup();
+                }
+                ImGui::SameLine();
+                if (ImGui::Button("No", ImVec2(120, 0)))
+                {
+                    ImGui::CloseCurrentPopup();
+                }
+                ImGui::EndPopup();
+            }
+
+            if (m_QuitConfirmed)
+            {
+                m_QuitConfirmed = false;
+                Close();
+            }
+        }
+    }
+
+    void OnWindowClose(const Event& event) override
+    {
+        m_ShowQuitConfirm = true;
     }
 
     void OnKeyPress(const Event& event) override
     {
-        if (event.key == GLFW_KEY_GRAVE_ACCENT) {
-            m_OverlayVisible = !m_OverlayVisible;   // ` 反折叠加层
+        if (event.key == GLFW_KEY_GRAVE_ACCENT)
+        {
+            SetImGuiEnabled(!GetImGuiEnabled());
         }
-        if (event.key == GLFW_KEY_F1) {
+        if (event.key == GLFW_KEY_F1)
+        {
             STATS.PrintComparison();
         }
-        if (event.key == GLFW_KEY_ESCAPE) {
-            Close();
-        }
     }
 
+
     void OnWindowResize(const Event& event) override
     {
         ENGINE_INFO("App: window resized to {}x{}", event.width, event.height);
     }
 
 private:
+    bool m_ShowQuitConfirm = false;
+    bool m_QuitConfirmed = false;
     EntityHandle m_Camera{}; // Scene::CreateEntity 之前为空
     EntityHandle m_Ground{};
     EntityHandle m_KeyLight{};
     std::vector<EntityHandle> m_Spinners;
-    bool m_OverlayVisible = true;
     f32 m_Time = 0.0f;
 };
 
@@ -227,10 +282,12 @@ int main()
 {
     SandboxApp app;
 
-    try {
+    try
+    {
         app.Run();
     }
-    catch (const std::exception& e) {
+    catch (const std::exception& e)
+    {
         ENGINE_FATAL("Exception: {}", e.what());
         return -1;
     }

Engine/include/Engine/Core/Application.h

@@ -26,6 +26,8 @@
 #include <chrono>
 #include <string>
 
+#include "Engine/ImGui/ImGuiLayer.h"
+
 namespace Engine {
 
     class Window;
@@ -59,8 +61,6 @@ namespace Engine {
         // 限帧目标最低 24fps（防止过低刷新导致交互卡死），无上限
         void SetVSync(bool vsync);
         bool GetVSync() const { return m_VSync; }
-        void SetLimitFps(bool on) { m_LimitFps = on; }
-        bool GetLimitFps() const { return m_LimitFps; }
         void SetTargetFps(f32 fps) { m_TargetFps = std::max(24.0f, fps); }
         f32 GetTargetFps() const { return m_TargetFps; }
 
@@ -72,6 +72,11 @@ namespace Engine {
         f32 GetDeltaTime() const { return m_DeltaTime; }
         u64 GetFrameCount() const { return m_FrameCount; }
 
+        // ImGui相关
+        void SetImGuiEnabled(const bool enable) { if (m_ImGuiLayer) m_ImGuiLayer->SetEnabled(enable); }
+        // 理论上ImGuiLayer不应该会空，暂时静默处理
+        bool GetImGuiEnabled() const { return m_ImGuiLayer ? m_ImGuiLayer->IsEnabled() : false; }
+
     protected:
         // ---- 生命周期钩子 ----
 
@@ -119,8 +124,7 @@ namespace Engine {
         u64 m_FrameCount = 0;
 
         // 帧率控制
-        bool m_VSync = true;        // 垂直同步（present 自带节奏）
-        bool m_LimitFps = false;    // 手动限帧开关（vsync 开启时不生效）
+        bool m_VSync = false;        // 垂直同步（present 自带节奏）
         f32 m_TargetFps = 60.0f;    // 限帧目标（≥24）
 
         std::chrono::steady_clock::time_point m_LastFrameTime;

Engine/include/Engine/Core/Window.h

@@ -87,6 +87,8 @@ namespace Engine {
         static void CursorPosCallback(GLFWwindow* window, double xpos, double ypos);
         static void ScrollCallback(GLFWwindow* window, double xoffset, double yoffset);
         static void WindowFocusCallback(GLFWwindow* window, int focused);
+
+        static void WindowCloseCallback(GLFWwindow* window);
     };
 
 } // namespace Engine

Engine/include/Engine/Vulkan/Swapchain.h

@@ -61,7 +61,7 @@ namespace Engine
 
         vk::Format m_Format;
         vk::Extent2D m_Extent;
-        bool m_VSync = true;
+        bool m_VSync = false;
     };
 } // namespace Engine
 

Engine/src/Core/Application.cpp

@@ -84,7 +84,7 @@ namespace Engine {
 
         OnInit();
 
-        while (m_Running && !m_Window->ShouldClose()) {
+        while (m_Running) {
             const auto frameStart = std::chrono::steady_clock::now();
 
             m_Window->PollEvents();
@@ -103,13 +103,10 @@ namespace Engine {
             const auto uiStart = std::chrono::steady_clock::now();
 
             // ---- UI 构建段：OnRenderOverlay 只"声明"控件，不直接碰 GPU ----
-            if (m_ImGuiLayer) {
+            if (m_ImGuiLayer && m_ImGuiLayer->IsEnabled())
+            {
                 m_ImGuiLayer->NewFrame();
-            }
-
                 OnRenderOverlay();
-
-            if (m_ImGuiLayer) {
                 m_ImGuiLayer->BuildDrawData();
             }
             const auto uiEnd = std::chrono::steady_clock::now();
@@ -120,7 +117,7 @@ namespace Engine {
 
             // ---- 帧率控制：vsync 开启时 present 自带节奏；否则按目标限帧 ----
             // 策略：先 sleep 到剩 ~2ms，再自旋——精度高且不烧 CPU
-            if (!m_VSync && m_LimitFps) {
+            if (!m_VSync) {
                 const auto deadline = frameStart +
                     std::chrono::microseconds(static_cast<long long>(
                         1e6 / m_TargetFps));
@@ -137,23 +134,6 @@ namespace Engine {
                     }
                 }
             }
-
-            // CPU 侧遥测（每 120 帧一行）：定位帧耗时的 CPU 归属
-            const auto frameEnd = std::chrono::steady_clock::now();
-            static u32 cpuTelemetryCount = 0;
-            if (++cpuTelemetryCount % 120 == 1) {
-                const f32 uiMs = std::chrono::duration<f32, std::milli>(
-                                     uiEnd - uiStart).count();
-                const f32 renderMs = std::chrono::duration<f32, std::milli>(
-                                         frameEnd - uiEnd).count();
-                const f32 updateMs = std::chrono::duration<f32, std::milli>(
-                                         uiStart - frameStart).count();
-                const f32 totalMs = std::chrono::duration<f32, std::milli>(
-                                        frameEnd - frameStart).count();
-                ENGINE_INFO("CPU times: update={:.2f}ms ui={:.2f}ms render={:.2f}ms total={:.2f}ms",
-                            updateMs, uiMs, renderMs, totalMs);
-            }
-
             ++m_FrameCount;
         }
 
@@ -182,7 +162,6 @@ namespace Engine {
 
     void Application::OnWindowClose(const Event& event)
     {
-        // 默认行为：直接退出。需要"退出确认"的程序覆写本钩子。
         Close();
     }
 

Engine/src/Core/Window.cpp

@@ -26,7 +26,7 @@ namespace Engine
 
     void Window::KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
     {
-        auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
+        const auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
         if (!self->m_EventCallback || key == GLFW_KEY_UNKNOWN) return;
 
         // UI 捕获键盘时，游戏侧不收键盘事件（ImGui 后端链式回调自行处理）
@@ -42,7 +42,7 @@ namespace Engine
 
     void Window::MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
     {
-        auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
+        const auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
         if (!self->m_EventCallback) return;
         if (self->m_MouseCapture && self->m_MouseCapture()) return;
 
@@ -55,7 +55,7 @@ namespace Engine
 
     void Window::CursorPosCallback(GLFWwindow* window, double xpos, double ypos)
     {
-        auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
+        const auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
         if (!self->m_EventCallback) return;
         if (self->m_MouseCapture && self->m_MouseCapture()) return;
 
@@ -68,7 +68,7 @@ namespace Engine
 
     void Window::ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
     {
-        auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
+        const auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
         if (!self->m_EventCallback) return;
         if (self->m_MouseCapture && self->m_MouseCapture()) return;
 
@@ -81,7 +81,7 @@ namespace Engine
 
     void Window::WindowFocusCallback(GLFWwindow* window, int focused)
     {
-        auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
+        const auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
         if (!self->m_EventCallback) return;
 
         Event e;
@@ -89,6 +89,16 @@ namespace Engine
         self->m_EventCallback(e);
     }
 
+    void Window::WindowCloseCallback(GLFWwindow* window)
+    {
+        const auto* self = static_cast<Window*>(glfwGetWindowUserPointer(window));
+        if (!self->m_EventCallback) return;
+
+        Event e;
+        e.type = EventType::WindowClose;
+        self->m_EventCallback(e);
+    }
+
     Window::Window(const std::string& title, u32 width, u32 height)
         : m_Width(width), m_Height(height), m_Title(title)
     {
@@ -100,6 +110,8 @@ namespace Engine
 
         glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
         // glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
+        glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GLFW_TRUE);
+        // 设置窗口为半透明
 
         m_Window = glfwCreateWindow(width, height, title.c_str(), nullptr, nullptr);
         if (!m_Window)
@@ -108,6 +120,7 @@ namespace Engine
             glfwTerminate();
             return;
         }
+        glfwSetWindowOpacity(m_Window, 0.5f);
 
         ENGINE_INFO("Window created: {} ({}x{})", title, width, height);
 
@@ -120,6 +133,8 @@ namespace Engine
         glfwSetCursorPosCallback(m_Window, CursorPosCallback);
         glfwSetScrollCallback(m_Window, ScrollCallback);
         glfwSetWindowFocusCallback(m_Window, WindowFocusCallback);
+
+        glfwSetWindowCloseCallback(m_Window, WindowCloseCallback);
     }
 
     Window::~Window()

Engine/src/Renderer/Model.cpp

@@ -178,7 +178,7 @@ Scope<Mesh> Model::ProcessMesh(aiMesh* mesh, const aiScene* scene)
 
         aiString path;
         if (material->GetTexture(aiTextureType_DIFFUSE, 0, &path) == AI_SUCCESS) {
-            std::filesystem::path modelDir =
+            const std::filesystem::path modelDir =
                 std::filesystem::path(m_ModelPath).parent_path();
             texturePath = (modelDir / path.C_Str()).string();
         }

Engine/src/Renderer/Renderer.cpp

@@ -475,7 +475,7 @@ namespace Engine
 
                 vk::ClearValue clearValue;
                 clearValue.color = vk::ClearColorValue(
-                    std::array<float, 4>{0.1f, 0.1f, 0.1f, 1.0f});
+                    std::array<float, 4>{0.0f, 0.0f, 0.0f, 0.0f});
 
                 vk::RenderingAttachmentInfo colorAttachment;
                 colorAttachment.setImageView(ctx.View(m_HDRColor))
@@ -850,6 +850,7 @@ namespace Engine
                 : 0.0f;
         }
 
+        /*
         // 控制台遥测：每 120 次读取（≈60 帧 @2 slot）输出一行
         static u32 telemetryCount = 0;
         if (++telemetryCount % 120 == 1) {
@@ -861,6 +862,7 @@ namespace Engine
             line += " collect=" + std::to_string(m_CollectMs).substr(0, 5) + "ms";
             ENGINE_INFO("{}", line);
         }
+    */
     }
 
     void Renderer::Render(ECS::Scene& scene, Assets::AssetManager& assets)

Engine/src/Vulkan/Swapchain.cpp

@@ -51,6 +51,21 @@ namespace Engine
         }
 
         vk::SwapchainCreateInfoKHR createInfo;
+
+        vk::CompositeAlphaFlagBitsKHR compositeAlpha = vk::CompositeAlphaFlagBitsKHR::eOpaque;
+        if (caps.supportedCompositeAlpha & vk::CompositeAlphaFlagBitsKHR::ePreMultiplied)
+        {
+            compositeAlpha = vk::CompositeAlphaFlagBitsKHR::ePreMultiplied;
+        }
+        else if (caps.supportedCompositeAlpha & vk::CompositeAlphaFlagBitsKHR::ePostMultiplied)
+        {
+            compositeAlpha = vk::CompositeAlphaFlagBitsKHR::ePostMultiplied;
+        }
+
+        ENGINE_INFO("supportedCompositeAlpha = 0x{:x}, chosen = 0x{:x}",
+                    static_cast<u32>(caps.supportedCompositeAlpha),
+                    static_cast<u32>(compositeAlpha));
+
         createInfo.setSurface(surface)
                   .setMinImageCount(imageCount)
                   .setImageFormat(surfaceFormat.format)
@@ -60,7 +75,7 @@ namespace Engine
                   .setImageUsage(vk::ImageUsageFlagBits::eColorAttachment)
                   .setImageSharingMode(vk::SharingMode::eExclusive)
                   .setPreTransform(caps.currentTransform)
-                  .setCompositeAlpha(vk::CompositeAlphaFlagBitsKHR::eOpaque)
+                  .setCompositeAlpha(compositeAlpha)
                   .setPresentMode(presentMode)
                   .setClipped(VK_TRUE)
                   .setOldSwapchain(nullptr);
@@ -95,10 +110,11 @@ namespace Engine
             m_ImageViews[i] = vkDevice.createImageView(viewInfo);
         }
 
-        ENGINE_INFO("Swapchain created: {}x{}, {} images, format={}",
+        ENGINE_INFO("Swapchain created: {}x{}, {} images, format={}, present={}",
                     m_Extent.width, m_Extent.height,
                     m_Images.size(),
-                    vk::to_string(m_Format));
+                    vk::to_string(m_Format),
+                    vk::to_string(presentMode));
     }
 
     void Swapchain::Destroy()
@@ -151,11 +167,14 @@ namespace Engine
 
     vk::PresentModeKHR Swapchain::ChoosePresentMode(const std::vector<vk::PresentModeKHR>& modes)
     {
-        // vsync 开：Mailbox（三缓冲垂直同步，低延迟）；关：Immediate
-        //（不限速，可能撕裂）。FIFO 是所有实现必须支持的兜底
+        // 实测 Wayland/NVIDIA：Mailbox 不阻塞应用循环（compositor 取最新
+        // 缓冲，应用层计数可远超刷新率）；Immediate 常不可用而退到 FIFO。
+        // 因此映射按"用户预期"定义：
+        //   vsync 开  → FIFO：应用被 pacing 到刷新率（真正的垂直同步）
+        //   vsync 关  → Mailbox：应用循环不限速（Wayland 下无撕裂）
         const vk::PresentModeKHR preferred = m_VSync
-            ? vk::PresentModeKHR::eMailbox
-            : vk::PresentModeKHR::eImmediate;
+            ? vk::PresentModeKHR::eFifo
+            : vk::PresentModeKHR::eMailbox;
 
         for (const auto& m : modes)
         {

shaders/tonemap.frag

@@ -25,8 +25,9 @@ vec3 acesFilm(vec3 x) {
 
 void main() {
     // bloom 在 HDR 域叠加（半分辨率模糊图线性采样上采样）
-    vec3 hdr = texture(hdrImage, fragUV).rgb
-             + texture(bloomImage, fragUV).rgb * pc.bloomStrength;
+    vec4 hdrTex = texture(hdrImage, fragUV);
+    vec3 hdr = hdrTex.rgb + texture(bloomImage, fragUV).rgb * pc.bloomStrength;
+    float alpha = hdrTex.a;
 
     hdr *= pc.exposure;
 
@@ -34,5 +35,5 @@ void main() {
         ? acesFilm(hdr)
         : clamp(hdr, 0.0, 1.0);
 
-    outColor = vec4(pow(mapped, vec3(1.0 / 2.2)), 1.0);
+    outColor = vec4(pow(mapped, vec3(1.0 / 2.2)), alpha);
 }