From 77f856714d5ebcd637461d0547f142239c987ebf Mon Sep 17 00:00:00 2001
From: wyc <1104749580@qq.com>
Date: Tue, 18 Aug 2026 12:15:41 +0800
Subject: [PATCH] =?UTF-8?q?=E5=90=8E=E5=8F=B0=E6=9C=8D=E5=8A=A1=E5=8D=8F?=
 =?UTF-8?q?=E7=A8=8B=E5=8C=96?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../src/renderive/scene/base/Scene_Base.cpp   | 16 ++++++-
 .../src/renderive/scene/base/Scene_Base.hpp   |  2 +
 .../src/renderive/scene/base/Scene_Base.inl   |  3 +-
 .../frame_control/Plot_Frame_Control.cpp      |  7 ++-
 .../frame_control/Plot_Frame_Control.h        |  1 +
 render_2D/render_2D/scene/Render_Scene_2D.cpp |  5 +-
 render_2D/render_2D/scene/Render_Scene_2D.h   |  1 +
 render_3D/render_3D/Render_Scene_3D.cpp       |  5 +-
 render_3D/render_3D/Render_Scene_3D.h         |  1 +
 .../frame_control/Point_Frame_Control.cpp     |  7 ++-
 .../frame_control/Point_Frame_Control.h       |  1 +
 web_server/app/Asio_WebSocket_Scene_Loop.h    | 14 ++++--
 web_server/app/Gallery_Plot_Session.cpp       | 45 ++++++++++++++++++
 web_server/app/Gallery_Plot_Session.h         |  2 +-
 web_server/app/Web_Plot_Session.cpp           | 46 +++++++++++++++----
 web_server/app/Web_Plot_Session.h             | 10 +++-
 .../app/common/Gallery_Scene_Interface.h      |  2 +
 web_server/app/render_2D/Gallery_Scene2D.cpp  | 11 ++++-
 web_server/app/render_3D/Gallery_Scene3D.cpp  | 10 +++-
 19 files changed, 164 insertions(+), 25 deletions(-)

diff --git a/Kernel/src/renderive/scene/base/Scene_Base.cpp b/Kernel/src/renderive/scene/base/Scene_Base.cpp
index 7ac5acf..c705789 100644
--- a/Kernel/src/renderive/scene/base/Scene_Base.cpp
+++ b/Kernel/src/renderive/scene/base/Scene_Base.cpp
@@ -762,7 +762,10 @@ Scene_Render_Result Scene_Base::render() {
 Scene_Render_Result Scene_Base::render(Abstract_Frame& frame) {
     return d_func().submit_render(&frame);
 }
-Scene_Render_Result Scene_Base::Impl::submit_render(Abstract_Frame* frame) {
+Scene_Render_Result Scene_Base::render(Abstract_Frame& frame, Scene_Render_Completion completion) {
+    return d_func().submit_render(&frame, std::move(completion));
+}
+Scene_Render_Result Scene_Base::Impl::submit_render(Abstract_Frame* frame, Scene_Render_Completion completion) {
     if (active_submitted_observer_scene_ == owner_) {
         std::lock_guard<std::recursive_mutex> lock(task_mutex_);
         ++deferred_render_count_;
@@ -802,6 +805,7 @@ Scene_Render_Result Scene_Base::Impl::submit_render(Abstract_Frame* frame) {
     task->topology =
     std::make_shared<Topology_Snapshot>(scene().topology_snapshot());
     task->completion = std::make_shared<Render_Completion>();
+    task->completion_callback = std::move(completion);
     const Capture_Frame_Ticket capture_ticket = capture_controller_.begin_frame();
     snapshot->capture_ticket_ = capture_ticket;
     task->snapshot = std::move(snapshot);
@@ -1526,6 +1530,16 @@ void Scene_Base::Impl::execute_render_task(std::shared_ptr<Render_Task> task) {
                << " pending_operations=" << pending_operations;
     });
     render_completed_.notify_all();
+    if (task->completion_callback) {
+        try {
+            task->completion_callback(error, exception);
+        }
+        catch (...) {
+            record_pending_exception(::renderive::error::capture(
+                "executing scene render completion callback",
+                std::current_exception()));
+        }
+    }
 }
 std::shared_ptr<Scene_Base::Impl::Compiled_Render_Plan> Scene_Base::Impl::compile_render_plan(
     const Frame_Render_Snapshot& snapshot) {
diff --git a/Kernel/src/renderive/scene/base/Scene_Base.hpp b/Kernel/src/renderive/scene/base/Scene_Base.hpp
index f89d88c..4575976 100644
--- a/Kernel/src/renderive/scene/base/Scene_Base.hpp
+++ b/Kernel/src/renderive/scene/base/Scene_Base.hpp
@@ -48,6 +48,7 @@ enum class Scene_Render_Result : std::uint8_t {
     external_failure,
     shutting_down
 };
+using Scene_Render_Completion = std::function<void(Scene_Render_Result, std::exception_ptr)>;
 enum class Scene_Edit_Error : std::uint8_t {
     none,
     empty_edit,
@@ -160,6 +161,7 @@ public:
     };
     Scene_Render_Result render();
     Scene_Render_Result render(Abstract_Frame& frame);
+    Scene_Render_Result render(Abstract_Frame& frame, Scene_Render_Completion completion);
     Scene_Render_Result wait_for_render();
     void publish_frame_state();
     void publish_frame_state(Abstract_Frame& frame);
diff --git a/Kernel/src/renderive/scene/base/Scene_Base.inl b/Kernel/src/renderive/scene/base/Scene_Base.inl
index 37bf647..5b022d7 100644
--- a/Kernel/src/renderive/scene/base/Scene_Base.inl
+++ b/Kernel/src/renderive/scene/base/Scene_Base.inl
@@ -75,6 +75,7 @@ public:
         std::shared_ptr<const Topology_Snapshot> topology;
         std::shared_ptr<Abstract_Frame::Render_State> frame;
         std::shared_ptr<Render_Completion> completion;
+        Scene_Render_Completion completion_callback;
     };
     class Execution_Context;
     class Render_Execution_Scope;
@@ -95,7 +96,7 @@ public:
     [[nodiscard]] const Composition_Relationships* composition() const noexcept;
     [[nodiscard]] Raster_Capabilities* raster() noexcept;
     [[nodiscard]] const Raster_Capabilities* raster() const noexcept;
-    [[nodiscard]] Scene_Render_Result submit_render(Abstract_Frame* frame);
+    [[nodiscard]] Scene_Render_Result submit_render(Abstract_Frame* frame, Scene_Render_Completion completion = {});
     void complete_pending_operation();
     void record_pending_exception(std::exception_ptr exception);
     void capture_edit_renderable(const Renderable& renderable);
diff --git a/render_2D/render_2D/frame_control/Plot_Frame_Control.cpp b/render_2D/render_2D/frame_control/Plot_Frame_Control.cpp
index cadd93c..232e8b7 100644
--- a/render_2D/render_2D/frame_control/Plot_Frame_Control.cpp
+++ b/render_2D/render_2D/frame_control/Plot_Frame_Control.cpp
@@ -47,6 +47,9 @@ std::shared_ptr<const Frame_Control_Strategy_Base> Plot_Frame_Control::runtime()
     return impl_->strategy;
 }
 auto Plot_Frame_Control::request(Render_Scene_2D& scene) -> Expected<void, Plot_Render_Frame_Error> {
+    return request(scene, {});
+}
+auto Plot_Frame_Control::request(Render_Scene_2D& scene, Scene_Render_Completion completion) -> Expected<void, Plot_Render_Frame_Error> {
     const bool prepared = visit(*impl_->strategy, [&scene](auto& strategy) {
         auto frame = strategy.acquire_painter();
         if (!frame) return false;
@@ -58,13 +61,13 @@ auto Plot_Frame_Control::request(Render_Scene_2D& scene) -> Expected<void, Plot_
         dynamic_cast<Manual_Strategy*>(impl_->strategy.get())) {
         if (strategy->refresh() != Manual_Refresh_Result::none) return unexpected(Plot_Render_Frame_Error::no_pending_frame);
     }
-    return visit(*impl_->strategy, [&scene](auto& strategy)
+    return visit(*impl_->strategy, [&scene, completion = std::move(completion)](auto& strategy) mutable
                      -> Expected<void, Plot_Render_Frame_Error> {
                      auto frame = strategy.acquire_renderer();
                      if (!frame)
                          return unexpected(
                              Plot_Render_Frame_Error::renderer_unavailable);
-                     const auto result = scene.Scene_Base::render(*frame);
+                     const auto result = scene.Scene_Base::render(*frame, std::move(completion));
                      if (result == Scene_Render_Result::none) return {};
                      const auto converted =
                      adapter::enum_cast<Plot_Render_Frame_Error>(result);
diff --git a/render_2D/render_2D/frame_control/Plot_Frame_Control.h b/render_2D/render_2D/frame_control/Plot_Frame_Control.h
index 4c05d95..4c398f5 100644
--- a/render_2D/render_2D/frame_control/Plot_Frame_Control.h
+++ b/render_2D/render_2D/frame_control/Plot_Frame_Control.h
@@ -14,6 +14,7 @@ public:
     [[nodiscard]] std::shared_ptr<Frame_Control_Strategy_Base> runtime();
     [[nodiscard]] std::shared_ptr<const Frame_Control_Strategy_Base> runtime() const;
     [[nodiscard]] auto request(Render_Scene_2D& scene) -> Expected<void, Plot_Render_Frame_Error>;
+    [[nodiscard]] auto request(Render_Scene_2D& scene, Scene_Render_Completion completion) -> Expected<void, Plot_Render_Frame_Error>;
     void replace(std::shared_ptr<Frame_Control_Strategy_Base> strategy);
 private:
     struct Impl;
diff --git a/render_2D/render_2D/scene/Render_Scene_2D.cpp b/render_2D/render_2D/scene/Render_Scene_2D.cpp
index ef15936..69a6f10 100644
--- a/render_2D/render_2D/scene/Render_Scene_2D.cpp
+++ b/render_2D/render_2D/scene/Render_Scene_2D.cpp
@@ -148,12 +148,15 @@ void detail::Render_Scene_2D::dispatch_event(const Event& event) {
     }
 }
 auto detail::Render_Scene_2D::render_frame() -> Expected<Plot_Render_Status, Plot_Render_Frame_Error> {
+    return render_frame({});
+}
+auto detail::Render_Scene_2D::render_frame(Scene_Render_Completion completion) -> Expected<Plot_Render_Status, Plot_Render_Frame_Error> {
     if (!view_active()) return Plot_Render_Status::view_inactive;
     const Size viewport = get<&State::viewport>();
     if (viewport.empty()) return Plot_Render_Status::empty_viewport;
     const auto started = std::chrono::steady_clock::now();
     try {
-        if (const auto result = d_func<Impl>().frame_control->request(*this); !result) return unexpected(result.error());
+        if (const auto result = d_func<Impl>().frame_control->request(*this, std::move(completion)); !result) return unexpected(result.error());
     }
     catch (...) {
         ::renderive::error::unexpected(
diff --git a/render_2D/render_2D/scene/Render_Scene_2D.h b/render_2D/render_2D/scene/Render_Scene_2D.h
index c69dec6..57346a0 100644
--- a/render_2D/render_2D/scene/Render_Scene_2D.h
+++ b/render_2D/render_2D/scene/Render_Scene_2D.h
@@ -174,6 +174,7 @@ public:
     [[nodiscard]] ::renderive_Owner<::renderive::Renderable> root_renderable() const;
     void dispatch_event(const Event& event);
     [[nodiscard]] auto render_frame() -> Expected<Plot_Render_Status, Plot_Render_Frame_Error>;
+    [[nodiscard]] auto render_frame(Scene_Render_Completion completion) -> Expected<Plot_Render_Status, Plot_Render_Frame_Error>;
     void with_frame(const std::function<void(Image_View)>& consumer);
     void activate_view();
     void deactivate_view() noexcept;
diff --git a/render_3D/render_3D/Render_Scene_3D.cpp b/render_3D/render_3D/Render_Scene_3D.cpp
index 4f1d8f3..ee0cf1c 100644
--- a/render_3D/render_3D/Render_Scene_3D.cpp
+++ b/render_3D/render_3D/Render_Scene_3D.cpp
@@ -507,7 +507,7 @@ Scene_Control_Error detail::Render_Scene_3D::dispatch(
     return Scene_Control_Error::none;
 }
 Frame_Request_Result detail::Render_Scene_3D::request_frame() {
-    const auto requested = d_func<Impl>().frame_control->request(*this);
+    const auto requested = request_frame({});
     if (requested != Frame_Request_Result::none) return requested;
     switch (wait_for_render()) {
     case Scene_Render_Result::none: return Frame_Request_Result::none;
@@ -521,6 +521,9 @@ Frame_Request_Result detail::Render_Scene_3D::request_frame() {
     }
     return Frame_Request_Result::external_failure;
 }
+Frame_Request_Result detail::Render_Scene_3D::request_frame(Scene_Render_Completion completion) {
+    return d_func<Impl>().frame_control->request(*this, std::move(completion));
+}
 std::shared_ptr<const Pixel_Frame> detail::Render_Scene_3D::latest_frame() const {
     return d_func<Impl>().latest_frame();
 }
diff --git a/render_3D/render_3D/Render_Scene_3D.h b/render_3D/render_3D/Render_Scene_3D.h
index a562049..e543aa5 100644
--- a/render_3D/render_3D/Render_Scene_3D.h
+++ b/render_3D/render_3D/Render_Scene_3D.h
@@ -149,6 +149,7 @@ public:
     [[nodiscard]] Scene_Control_Error dispatch(
         const ::renderive::Event& event);
     [[nodiscard]] Frame_Request_Result request_frame();
+    [[nodiscard]] Frame_Request_Result request_frame(Scene_Render_Completion completion);
     [[nodiscard]] std::shared_ptr<const Pixel_Frame> latest_frame() const;
     ~Render_Scene_3D() override;
 private:
diff --git a/render_3D/render_3D/frame_control/Point_Frame_Control.cpp b/render_3D/render_3D/frame_control/Point_Frame_Control.cpp
index 9672c8e..8a10127 100644
--- a/render_3D/render_3D/frame_control/Point_Frame_Control.cpp
+++ b/render_3D/render_3D/frame_control/Point_Frame_Control.cpp
@@ -45,6 +45,9 @@ std::shared_ptr<const Frame_Control_Strategy_Base> Point_Frame_Control::runtime(
     return impl_->strategy;
 }
 Frame_Request_Result Point_Frame_Control::request(Render_Scene_3D& scene) {
+    return request(scene, {});
+}
+Frame_Request_Result Point_Frame_Control::request(Render_Scene_3D& scene, Scene_Render_Completion completion) {
     const auto prepared = visit(*impl_->strategy, [&scene](auto& strategy) {
         auto frame = strategy.acquire_painter();
         if (!frame) return false;
@@ -53,10 +56,10 @@ Frame_Request_Result Point_Frame_Control::request(Render_Scene_3D& scene) {
     });
     if (!prepared) return Frame_Request_Result::painter_unavailable;
     if (auto* strategy = dynamic_cast<Manual_Strategy*>(impl_->strategy.get()); strategy && strategy->refresh() != Manual_Refresh_Result::none) return Frame_Request_Result::no_pending_frame;
-    return visit(*impl_->strategy, [&scene](auto& strategy) {
+    return visit(*impl_->strategy, [&scene, completion = std::move(completion)](auto& strategy) mutable {
         auto frame = strategy.acquire_renderer();
         if (!frame) return Frame_Request_Result::renderer_unavailable;
-        const auto result = scene.Scene_Base::render(*frame);
+        const auto result = scene.Scene_Base::render(*frame, std::move(completion));
         const auto converted =
         adapter::enum_cast<Frame_Request_Result>(result);
         if (!converted)
diff --git a/render_3D/render_3D/frame_control/Point_Frame_Control.h b/render_3D/render_3D/frame_control/Point_Frame_Control.h
index 4717f4d..2086d7d 100644
--- a/render_3D/render_3D/frame_control/Point_Frame_Control.h
+++ b/render_3D/render_3D/frame_control/Point_Frame_Control.h
@@ -14,6 +14,7 @@ public:
     [[nodiscard]] std::shared_ptr<Frame_Control_Strategy_Base> runtime();
     [[nodiscard]] std::shared_ptr<const Frame_Control_Strategy_Base> runtime() const;
     [[nodiscard]] Frame_Request_Result request(Render_Scene_3D& scene);
+    [[nodiscard]] Frame_Request_Result request(Render_Scene_3D& scene, Scene_Render_Completion completion);
     void replace(std::shared_ptr<Frame_Control_Strategy_Base> strategy);
 private:
     struct Impl;
diff --git a/web_server/app/Asio_WebSocket_Scene_Loop.h b/web_server/app/Asio_WebSocket_Scene_Loop.h
index 57760ce..8251a09 100644
--- a/web_server/app/Asio_WebSocket_Scene_Loop.h
+++ b/web_server/app/Asio_WebSocket_Scene_Loop.h
@@ -67,11 +67,19 @@ private:
                     co_return;
                 throw asio::system_error(error);
             }
-            auto response = session.handle(event);
+            using Completion_Channel = asio::experimental::concurrent_channel<void(asio::error_code, Web_Async_Response)>;
+            auto completion_channel = std::make_shared<Completion_Channel>(events_.get_executor(), 1);
+            session.async_handle(event, [completion_channel](Web_Async_Response response) {
+                completion_channel->try_send(asio::error_code{}, std::move(response));
+            });
+            asio::error_code completion_error;
+            auto completed = co_await completion_channel->async_receive(asio::redirect_error(asio::use_awaitable, completion_error));
+            if (completion_error) throw asio::system_error(completion_error);
+            if (completed.exception) std::rethrow_exception(completed.exception);
             if (stopped_.load(std::memory_order_acquire))
                 co_return;
-            if (response)
-                response_handler_(std::move(*response));
+            if (completed.response)
+                response_handler_(std::move(*completed.response));
         }
     }
     asio::experimental::concurrent_channel<void(asio::error_code, Web_Event)> events_;
diff --git a/web_server/app/Gallery_Plot_Session.cpp b/web_server/app/Gallery_Plot_Session.cpp
index 928c7e2..c42f0f8 100644
--- a/web_server/app/Gallery_Plot_Session.cpp
+++ b/web_server/app/Gallery_Plot_Session.cpp
@@ -8,6 +8,7 @@
 #include <chrono>
 #include <cmath>
 #include <cstdint>
+#include <exception>
 #include <optional>
 #include <string>
 #include <string_view>
@@ -308,6 +309,40 @@ struct Gallery_Plot_Session::Impl {
             return std::nullopt;
         return Web_Response{Web_Response_Type::Pixels, std::move(*pixels)};
     }
+    void async_handle_frame_request(Web_Response_Completion completion) {
+        const auto request_started = std::chrono::steady_clock::now();
+        if (!scene) {
+            completion({});
+            return;
+        }
+        const bool submitted = scene->async_request_frame(
+            [this, request_started, completion](Scene_Render_Result render_result, std::exception_ptr exception) mutable {
+                if (exception) {
+                    completion({{}, std::move(exception)});
+                    return;
+                }
+                if (render_result != Scene_Render_Result::none) {
+                    completion({});
+                    return;
+                }
+                try {
+                    const auto encode_started = std::chrono::steady_clock::now();
+                    auto pixels = scene->encode_latest_pixels();
+                    const auto encode_finished = std::chrono::steady_clock::now();
+                    if (pixels)
+                        scene->record_pixel_response(request_started, encode_started, encode_finished, pixels->size());
+                    if (!pixels) {
+                        completion({});
+                        return;
+                    }
+                    completion({Web_Response{Web_Response_Type::Pixels, std::move(*pixels)}, {}});
+                }
+                catch (...) {
+                    completion({{}, std::current_exception()});
+                }
+            });
+        if (!submitted) completion({});
+    }
     std::optional<Web_Response> handle(const Web_Event& event) {
         if (std::holds_alternative<Frame_Request>(event))
             return handle_frame_request();
@@ -336,10 +371,20 @@ struct Gallery_Plot_Session::Impl {
             },
             event);
     }
+    void async_handle(const Web_Event& event, Web_Response_Completion completion) {
+        if (std::holds_alternative<Frame_Request>(event)) {
+            async_handle_frame_request(std::move(completion));
+            return;
+        }
+        completion({handle(event), {}});
+    }
 };
 Gallery_Plot_Session::Gallery_Plot_Session() : impl_(std::make_unique<Impl>()) {}
 Gallery_Plot_Session::~Gallery_Plot_Session() = default;
 std::optional<Web_Response> Gallery_Plot_Session::handle(const Web_Event& event) {
     return impl_->handle(event);
 }
+void Gallery_Plot_Session::async_handle(const Web_Event& event, Web_Response_Completion completion) {
+    impl_->async_handle(event, std::move(completion));
+}
 } // namespace renderive::web
diff --git a/web_server/app/Gallery_Plot_Session.h b/web_server/app/Gallery_Plot_Session.h
index 11cc377..4c093f9 100644
--- a/web_server/app/Gallery_Plot_Session.h
+++ b/web_server/app/Gallery_Plot_Session.h
@@ -15,7 +15,7 @@ public:
     Gallery_Plot_Session& operator=(const Gallery_Plot_Session&) = delete;
 
     [[nodiscard]] std::optional<Web_Response> handle(const Web_Event& event);
-
+    void async_handle(const Web_Event& event, Web_Response_Completion completion);
 private:
     struct Impl;
     std::unique_ptr<Impl> impl_;
diff --git a/web_server/app/Web_Plot_Session.cpp b/web_server/app/Web_Plot_Session.cpp
index 2a871dd..1c2731c 100644
--- a/web_server/app/Web_Plot_Session.cpp
+++ b/web_server/app/Web_Plot_Session.cpp
@@ -25,20 +25,21 @@ struct Web_Plot_Session::Impl {
         scene = std::move(*built_scene);
         scene->activate_view();
     }
+    std::optional<Web_Response> encode_frame() {
+        std::string pixels;
+        scene->with_frame([&](Image_View image) {
+            pixels = encode_pixel_frame(image, ++sequence);
+        });
+        if (pixels.empty()) return std::nullopt;
+        return Web_Response{Web_Response_Type::Pixels, std::move(pixels)};
+    }
     std::optional<Web_Response> handle(const Web_Event& event) {
         return std::visit([this](const auto& value) -> std::optional<Web_Response> {
             using T = std::decay_t<decltype(value)>;
             if constexpr (std::same_as<T, Frame_Request>) {
                 const auto result = scene->render_frame();
-                if (!result || scene->wait_for_render() != Scene_Render_Result::none)
-                    return std::nullopt;
-                std::string pixels;
-                scene->with_frame([&](Image_View image) {
-                    pixels = encode_pixel_frame(image, ++sequence);
-                });
-                if (pixels.empty()) return std::nullopt;
-                return Web_Response{Web_Response_Type::Pixels,
-                                    std::move(pixels)};
+                if (!result || scene->wait_for_render() != Scene_Render_Result::none) return std::nullopt;
+                return encode_frame();
             } else if constexpr (std::same_as<T, Viewport_Resize>) {
                 viewport = value.size;
                 rebuild();
@@ -48,10 +49,37 @@ struct Web_Plot_Session::Impl {
             return std::nullopt;
         }, event);
     }
+    void async_handle(const Web_Event& event, Web_Response_Completion completion) {
+        if (!std::holds_alternative<Frame_Request>(event)) {
+            completion({handle(event), {}});
+            return;
+        }
+        const auto result = scene->render_frame(
+            [this, completion](Scene_Render_Result render_result, std::exception_ptr exception) mutable {
+                if (exception) {
+                    completion({{}, std::move(exception)});
+                    return;
+                }
+                if (render_result != Scene_Render_Result::none) {
+                    completion({});
+                    return;
+                }
+                try {
+                    completion({encode_frame(), {}});
+                }
+                catch (...) {
+                    completion({{}, std::current_exception()});
+                }
+            });
+        if (!result || *result != Plot_Render_Status::rendered) completion({});
+    }
 };
 Web_Plot_Session::Web_Plot_Session() : impl_(std::make_unique<Impl>()) {}
 Web_Plot_Session::~Web_Plot_Session() = default;
 std::optional<Web_Response> Web_Plot_Session::handle(const Web_Event& event) {
     return impl_->handle(event);
 }
+void Web_Plot_Session::async_handle(const Web_Event& event, Web_Response_Completion completion) {
+    impl_->async_handle(event, std::move(completion));
+}
 } // namespace renderive::web
diff --git a/web_server/app/Web_Plot_Session.h b/web_server/app/Web_Plot_Session.h
index d76fef1..60d0a8f 100644
--- a/web_server/app/Web_Plot_Session.h
+++ b/web_server/app/Web_Plot_Session.h
@@ -2,6 +2,8 @@
 
 #include "Web_Event.h"
 
+#include <exception>
+#include <functional>
 #include <memory>
 #include <optional>
 #include <string>
@@ -14,7 +16,11 @@ struct Web_Response {
     Web_Response_Type type = Web_Response_Type::Pixels;
     std::string payload;
 };
-
+struct Web_Async_Response {
+    std::optional<Web_Response> response;
+    std::exception_ptr exception;
+};
+using Web_Response_Completion = std::function<void(Web_Async_Response)>;
 class Web_Plot_Session final {
 public:
     Web_Plot_Session();
@@ -23,7 +29,7 @@ public:
     Web_Plot_Session& operator=(const Web_Plot_Session&) = delete;
 
     [[nodiscard]] std::optional<Web_Response> handle(const Web_Event& event);
-
+    void async_handle(const Web_Event& event, Web_Response_Completion completion);
 private:
     struct Impl;
     std::unique_ptr<Impl> impl_;
diff --git a/web_server/app/common/Gallery_Scene_Interface.h b/web_server/app/common/Gallery_Scene_Interface.h
index ebc1baa..5a933c9 100644
--- a/web_server/app/common/Gallery_Scene_Interface.h
+++ b/web_server/app/common/Gallery_Scene_Interface.h
@@ -3,6 +3,7 @@
 #include "Gallery_Performance_Types.h"
 #include "Gallery_Types.h"
 #include "adminive/adminive.hpp"
+#include <renderive/scene/base/Scene_Base.hpp>
 #include <nlohmann/json.hpp>
 #include <chrono>
 #include <cstddef>
@@ -22,6 +23,7 @@ public:
     virtual void resize(int width, int height) = 0;
     virtual void dispatch(const Gallery_Input_Event& event) = 0;
     [[nodiscard]] virtual bool request_frame() = 0;
+    [[nodiscard]] virtual bool async_request_frame(Scene_Render_Completion completion) = 0;
     [[nodiscard]] virtual std::optional<std::string> encode_latest_pixels() = 0;
     virtual void record_pixel_response(std::chrono::steady_clock::time_point request_started, std::chrono::steady_clock::time_point encode_started, std::chrono::steady_clock::time_point encode_finished, std::size_t pixel_bytes) = 0;
     [[nodiscard]] virtual std::string action(const Gallery_Action_Request& request, bool& recognized) = 0;
diff --git a/web_server/app/render_2D/Gallery_Scene2D.cpp b/web_server/app/render_2D/Gallery_Scene2D.cpp
index 0591611..6ee3c08 100644
--- a/web_server/app/render_2D/Gallery_Scene2D.cpp
+++ b/web_server/app/render_2D/Gallery_Scene2D.cpp
@@ -26,6 +26,7 @@
 #include <span>
 #include <stdexcept>
 #include <string>
+#include <utility>
 #include <vector>
 
 namespace renderive::web {
@@ -159,7 +160,15 @@ public:
         ++render_count_;
         return true;
     }
-
+    bool async_request_frame(Scene_Render_Completion completion) override {
+        update_samples();
+        const auto result = scene_->render_frame(
+            [this, completion = std::move(completion)](Scene_Render_Result render_result, std::exception_ptr exception) mutable {
+                if (!exception && render_result == Scene_Render_Result::none) ++render_count_;
+                completion(render_result, std::move(exception));
+            });
+        return result && *result == Plot_Render_Status::rendered;
+    }
     std::optional<std::string> encode_latest_pixels() override {
         std::string result;
         scene_->with_frame([&](Image_View image) {
diff --git a/web_server/app/render_3D/Gallery_Scene3D.cpp b/web_server/app/render_3D/Gallery_Scene3D.cpp
index 2f76af2..74ae953 100644
--- a/web_server/app/render_3D/Gallery_Scene3D.cpp
+++ b/web_server/app/render_3D/Gallery_Scene3D.cpp
@@ -13,6 +13,7 @@
 #include <memory>
 #include <stdexcept>
 #include <string>
+#include <utility>
 #include <vector>
 
 namespace renderive::web {
@@ -137,7 +138,14 @@ public:
         ++render_count_;
         return true;
     }
-
+    bool async_request_frame(Scene_Render_Completion completion) override {
+        const auto result = scene_->request_frame(
+            [this, completion = std::move(completion)](Scene_Render_Result render_result, std::exception_ptr exception) mutable {
+                if (!exception && render_result == Scene_Render_Result::none) ++render_count_;
+                completion(render_result, std::move(exception));
+            });
+        return result == Frame_Request_Result::none;
+    }
     std::optional<std::string> encode_latest_pixels() override {
         const auto frame = scene_->latest_frame();
         if (!frame || frame->rgba8.empty()) return std::nullopt;