Add real-time MoorDyn mooring line visualization to VSG GUI

Author: dav-og

CMakeLists.txt

@@ -509,6 +509,7 @@ if(HYDROCHRONO_ENABLE_VSG)
       src/gui/vsg_gui_component.cpp
       src/gui/vsg_lighting.cpp
       src/gui/vsg_materials.cpp
+      src/gui/vsg_mooring_lines.cpp
       src/gui/vsg_water_surface.cpp
       src/gui/vsg_radiation_surface.cpp
   )
@@ -517,6 +518,7 @@ if(HYDROCHRONO_ENABLE_VSG)
       src/gui/vsg_gui_component.h
       src/gui/vsg_lighting.h
       src/gui/vsg_materials.h
+      src/gui/vsg_mooring_lines.h
       src/gui/vsg_water_surface.h
       src/gui/vsg_radiation_surface.h
   )

demos/rm3/demo_rm3_mooring.cpp

@@ -135,6 +135,12 @@ int main(int argc, char* argv[]) {
     ui.SetCamera(0, -50, -10, 0, 0, -10);
     ui.SetWaveModel(my_hydro_inputs);
 
+#ifdef HYDROCHRONO_HAVE_MOORDYN
+    ui.SetMooringLineProvider([&hydro_forces]() {
+        return hydro_forces.GetMooringLineStates();
+    });
+#endif
+
     while (system.GetChTime() <= simulationDuration) {
         if (ui.IsRunning(timestep) == false) break;
 

include/hydroc/gui/guihelper.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <hydroc/gui/mooring_viz_data.h>
+
 #include <memory>
 
 namespace chrono {
@@ -61,6 +63,14 @@ class UI {
     virtual void SetWaterGridExtent(double width, double length,
                                     double center_x = 0.0, double center_y = 0.0);
 
+    /**@brief Set a callback that provides mooring line node positions each frame.
+     *
+     * When set, the GUI will call the provider every frame to obtain line
+     * geometry and render tube meshes for each mooring line.
+     * Call after Init() and before the simulation loop.
+     */
+    virtual void SetMooringLineProvider(MooringVizProvider provider);
+
     /**@brief return the internal system.
      *
      * Should be called after init.
@@ -90,6 +100,7 @@ class GUI : public UI {
     void SetWaveModel(std::shared_ptr<WaveBase> wave) override;
     void SetWaterGridExtent(double width, double length,
                             double center_x = 0.0, double center_y = 0.0) override;
+    void SetMooringLineProvider(MooringVizProvider provider) override;
 
   private:
     std::shared_ptr<hydroc::gui::GUIImpl> pImpl;

include/hydroc/gui/mooring_viz_data.h

@@ -0,0 +1,39 @@
+/// @file mooring_viz_data.h
+/// @brief Lightweight data types for mooring-line visualization.
+///
+/// Header-only with no MoorDyn or Eigen dependencies so that both the
+/// physics library (HydroChrono) and the visualization library
+/// (HydroChronoGUI) can include it without pulling in heavy headers.
+#pragma once
+
+#include <array>
+#include <functional>
+#include <vector>
+
+namespace hydroc {
+namespace gui {
+
+/// MoorDyn connection-point classification.
+/// Values intentionally match the MoorDyn C API convention.
+enum class MooringPointType : int {
+    kCoupled = -1,  ///< Vessel fairlead (driven by the coupled body).
+    kFree    =  0,  ///< Free point / clump weight / buoy.
+    kFixed   =  1,  ///< Seabed anchor or fixed attachment.
+};
+
+/// Sentinel value used for intermediate (non-endpoint) node markers.
+inline constexpr int kIntermediateNode = -99;
+
+/// Per-line visualization payload: ordered node positions along the line
+/// plus the MoorDyn point type at each endpoint.
+struct MooringLineVizData {
+    std::vector<std::array<double, 3>> node_positions;
+    MooringPointType start_point_type = MooringPointType::kFree;
+    MooringPointType end_point_type   = MooringPointType::kFree;
+};
+
+/// Callback the GUI invokes each frame to fetch current line geometry.
+using MooringVizProvider = std::function<std::vector<MooringLineVizData>()>;
+
+}  // namespace gui
+}  // namespace hydroc

include/hydroc/hydro_system.h

@@ -69,6 +69,7 @@
 // MoorDyn mooring configuration
 #ifdef HYDROCHRONO_HAVE_MOORDYN
 #include <hydroc/config/moordyn_config.h>
+#include <hydroc/gui/mooring_viz_data.h>
 #endif
 
 namespace hydrochrono::hydro {
@@ -454,6 +455,15 @@ class HydroSystem {
     void SetMoorDynConfig(const MoorDynConfig& config) {
         moordyn_config_ = config;
     }
+
+    /**
+     * @brief Get current mooring line node positions for visualization.
+     *
+     * Returns one entry per MoorDyn line, each containing the ordered node
+     * positions along the line.  Returns an empty vector when MoorDyn is
+     * not active or no lines exist.
+     */
+    std::vector<hydroc::gui::MooringLineVizData> GetMooringLineStates() const;
 #endif
 
     /**

src/gui/guihelper.cpp

@@ -38,6 +38,10 @@ void UI::SetWaterGridExtent(double /*width*/, double /*length*/,
     // Default (headless) UI does not render water surface.
 }
 
+void UI::SetMooringLineProvider(MooringVizProvider /*provider*/) {
+    // Default (headless) UI does not render mooring lines.
+}
+
 // -----------------------------------------------------------------------------
 
 GUI::GUI() {
@@ -72,3 +76,7 @@ void GUI::SetWaveModel(std::shared_ptr<WaveBase> wave) {
 void GUI::SetWaterGridExtent(double width, double length, double center_x, double center_y) {
     pImpl->SetWaterGridExtent(width, length, center_x, center_y);
 }
+
+void GUI::SetMooringLineProvider(MooringVizProvider provider) {
+    pImpl->SetMooringLineProvider(std::move(provider));
+}

src/gui/guihelperVSG.cpp

@@ -11,6 +11,7 @@
 #include "vsg_gui_component.h"
 #include "vsg_lighting.h"
 #include "vsg_materials.h"
+#include "vsg_mooring_lines.h"
 #include "vsg_radiation_surface.h"
 #include "vsg_water_surface.h"
 
@@ -128,6 +129,10 @@ void GUIImplVSG::SetWaterGridExtent(double width, double length, double center_x
               << ", center: (" << center_x << ", " << center_y << ")" << std::endl;
 }
 
+void GUIImplVSG::SetMooringLineProvider(MooringVizProvider provider) {
+    mooring_provider_ = std::move(provider);
+}
+
 void GUIImplVSG::EnsureWaterSurface() {
     // Require both system and visual system to be valid.
     if (!system_ || !pVis) {
@@ -179,9 +184,30 @@ bool GUIImplVSG::IsRunning(double timestep) {
         return false;
     }
 
-    // Ensure water surface exists (every frame check; returns early if already done).
+    // Reserve a scene-graph group for mooring geometry before the water
+    // surface is created, so opaque mooring lines are rendered first and
+    // remain visible through the transparent free surface.
+    if (mooring_provider_ && !mooring_scene_group_) {
+        if (auto scene = pVis->GetVSGScene()) {
+            mooring_scene_group_ = vsg::Group::create();
+            scene->addChild(mooring_scene_group_);
+        }
+    }
+
     EnsureWaterSurface();
 
+    // Mooring line visualisation (lazy-initialised on first valid data).
+    if (mooring_provider_) {
+        auto line_data = mooring_provider_();
+        if (!line_data.empty()) {
+            if (!mooring_viz_)
+                mooring_viz_ = std::make_unique<MooringLinesViz>();
+            if (!mooring_viz_->IsInitializedFor(pVis.get()))
+                mooring_viz_->Initialize(pVis.get(), line_data, mooring_scene_group_);
+            mooring_viz_->Update(line_data);
+        }
+    }
+
     // Handle viewer settings changes.
     if (viewer_settings_ && animated_water_) {
         // Handle visibility toggle.

src/gui/guihelper_impl.h

@@ -48,6 +48,7 @@ class GUIImpl {
     virtual void SetWaveModel(std::shared_ptr<WaveBase> /*wave*/) {}
     virtual void SetWaterGridExtent(double /*width*/, double /*length*/,
                                      double /*center_x*/, double /*center_y*/) {}
+    virtual void SetMooringLineProvider(MooringVizProvider /*provider*/) {}
 };
 
 #ifdef HYDROCHRONO_HAVE_IRRLICHT
@@ -70,8 +71,9 @@ class GUIImplIRR : public GUIImpl {
 #endif
 
 #ifdef HYDROCHRONO_HAVE_VSG
-// Forward declarations (defined in vsg_water_surface.h, vsg_gui_component.h).
+// Forward declarations (defined in vsg_water_surface.h, vsg_gui_component.h, vsg_mooring_lines.h).
 class AnimatedWaterSurface;
+class MooringLinesViz;
 struct ViewerSettings;
 
 class GUIImplVSG : public GUIImpl {
@@ -86,6 +88,7 @@ class GUIImplVSG : public GUIImpl {
     virtual bool IsRunning(double timestep) override;
     virtual void SetWaveModel(std::shared_ptr<WaveBase> wave) override;
     virtual void SetWaterGridExtent(double width, double length, double center_x, double center_y) override;
+    virtual void SetMooringLineProvider(MooringVizProvider provider) override;
 
   private:
     /// Ensure water surface is created (animated if wave model set, static otherwise).
@@ -100,6 +103,10 @@ class GUIImplVSG : public GUIImpl {
     chrono::ChSystem* system_ = nullptr;
     std::unique_ptr<AnimatedWaterSurface> animated_water_;
     std::unique_ptr<ViewerSettings> viewer_settings_;
+
+    MooringVizProvider mooring_provider_;
+    std::unique_ptr<MooringLinesViz> mooring_viz_;
+    vsg::ref_ptr<vsg::Group> mooring_scene_group_;
 };
 #endif