Lock the ImGui font atlas when processing a frame

scwx-qt/source/scwx/qt/manager/font_manager.cpp

@@ -45,12 +45,19 @@ public:
                                    const std::vector<std::string>& styles);
 
    std::string fontCachePath_ {};
+
+   std::shared_mutex imguiFontAtlasMutex_ {};
 };
 
 FontManager::FontManager() : p(std::make_unique<Impl>()) {}
 
 FontManager::~FontManager() {};
 
+std::shared_mutex& FontManager::imgui_font_atlas_mutex()
+{
+   return p->imguiFontAtlasMutex_;
+}
+
 std::shared_ptr<types::ImGuiFont>
 FontManager::GetImGuiFont(const std::string&               family,
                           const std::vector<std::string>&  styles,

scwx-qt/source/scwx/qt/manager/font_manager.hpp

@@ -2,6 +2,8 @@
 
 #include <scwx/qt/types/imgui_font.hpp>
 
+#include <shared_mutex>
+
 #include <QObject>
 
 namespace scwx
@@ -19,6 +21,8 @@ public:
    explicit FontManager();
    ~FontManager();
 
+   std::shared_mutex& imgui_font_atlas_mutex();
+
    std::shared_ptr<types::ImGuiFont>
    GetImGuiFont(const std::string&               family,
                 const std::vector<std::string>&  styles,

scwx-qt/source/scwx/qt/map/map_widget.cpp

@@ -1,5 +1,6 @@
 #include <scwx/qt/map/map_widget.hpp>
 #include <scwx/qt/gl/gl.hpp>
+#include <scwx/qt/manager/font_manager.hpp>
 #include <scwx/qt/manager/placefile_manager.hpp>
 #include <scwx/qt/manager/radar_product_manager.hpp>
 #include <scwx/qt/manager/settings_manager.hpp>
@@ -1028,6 +1029,10 @@ void MapWidget::paintGL()
    // Setup ImGui Frame
    ImGui::SetCurrentContext(p->imGuiContext_);
 
+   // Lock ImGui font atlas prior to new ImGui frame
+   std::shared_lock imguiFontAtlasLock {
+      manager::FontManager::Instance().imgui_font_atlas_mutex()};
+
    // Start ImGui Frame
    ImGui_ImplQt_NewFrame(this);
    ImGui_ImplOpenGL3_NewFrame();
@@ -1059,6 +1064,9 @@ void MapWidget::paintGL()
    ImGui::Render();
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
 
+   // Unlock ImGui font atlas after rendering
+   imguiFontAtlasLock.unlock();
+
    // Paint complete
    Q_EMIT WidgetPainted();
 }

scwx-qt/source/scwx/qt/ui/imgui_debug_widget.cpp

@@ -1,4 +1,5 @@
 #include <scwx/qt/ui/imgui_debug_widget.hpp>
+#include <scwx/qt/manager/font_manager.hpp>
 #include <scwx/qt/model/imgui_context_model.hpp>
 
 #include <set>
@@ -109,6 +110,10 @@ void ImGuiDebugWidget::paintGL()
 {
    ImGui::SetCurrentContext(p->currentContext_);
 
+   // Lock ImGui font atlas prior to new ImGui frame
+   std::shared_lock imguiFontAtlasLock {
+      manager::FontManager::Instance().imgui_font_atlas_mutex()};
+
    ImGui_ImplQt_NewFrame(this);
    ImGui_ImplOpenGL3_NewFrame();
 
@@ -131,6 +136,9 @@ void ImGuiDebugWidget::paintGL()
 
    ImGui::Render();
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+   // Unlock ImGui font atlas after rendering
+   imguiFontAtlasLock.unlock();
 }
 
 } // namespace ui