Add animated free-surface visualization driven by wave model

Add a real-time animated water surface to the VSG viewer.

- Renders a translucent ocean surface whose elevation follows the active wave model.
- Updates mesh vertices each frame using WaveBase::GetElevation(x,y,t).
- Computes per-vertex normals for correct lighting on wave slopes.
- Uses dynamic VSG vertex buffers and robust lifecycle handling across simulations.
- Falls back to a static plane when no wave model is present.

Pure visualization feature; no impact on hydrodynamics or solver behavior.

Author: dav-og

demos/oswec/demo_oswec_reg_waves.cpp

@@ -215,6 +215,7 @@ int main(int argc, char* argv[]) {
         // main simulation loop
         ui.Init(&system, "OSWEC - Regular Waves");
         ui.SetCamera(0, -50, -10, 0, 0, -10);
+        ui.SetWaveModel(my_hydro_inputs);  // Enable animated water surface
 
         while (system.GetChTime() <= simulationDuration) {
             if (ui.IsRunning(timestep) == false) break;

demos/rm3/demo_rm3_reg_waves.cpp

@@ -146,6 +146,7 @@ int main(int argc, char* argv[]) {
     // main simulation loop
     ui.Init(&system, "RM3 - Regular Wave Test");
     ui.SetCamera(0, -50, -10, 0, 0, -10);
+    ui.SetWaveModel(my_hydro_inputs);  // Enable animated water surface
 
     while (system.GetChTime() <= simulationDuration) {
         if (ui.IsRunning(timestep) == false) break;

demos/sphere/demo_sphere_irreg_waves.cpp

@@ -159,6 +159,7 @@ int main(int argc, char* argv[]) {
     // main simulation loop
     ui.Init(&system, "Sphere - Irregular Waves Test");
     ui.SetCamera(8, -25, 15, 0, 0, 0);
+    ui.SetWaveModel(my_hydro_inputs);  // Enable animated water surface
 
     while (system.GetChTime() <= simulationDuration) {
         if (ui.IsRunning(timestep) == false) break;

demos/sphere/demo_sphere_reg_waves.cpp

@@ -127,6 +127,7 @@ int main(int argc, char* argv[]) {
         // main simulation loop
         ui.Init(&system, "Sphere - Regular Waves Test");
         ui.SetCamera(8, -25, 15, 0, 0, 0);
+        ui.SetWaveModel(my_hydro_inputs);  // Enable animated water surface
 
         while (system.GetChTime() <= simulation_duration) {
             if (ui.IsRunning(timestep) == false) break;

include/hydroc/gui/guihelper.h

@@ -6,6 +6,9 @@ namespace chrono {
 class ChSystem;
 }
 
+// Forward declaration for wave model
+class WaveBase;
+
 namespace hydroc {
 namespace gui {
 
@@ -36,6 +39,15 @@ class UI {
      */
     virtual bool IsRunning(double timestep);
 
+    /**@brief Set the wave model for animated free-surface rendering.
+     *
+     * Should be called after Init() and before the simulation loop.
+     * If not called, a static flat water plane is rendered.
+     *
+     * @param wave Shared pointer to the wave model (may be nullptr for still water).
+     */
+    virtual void SetWaveModel(std::shared_ptr<WaveBase> wave);
+
     /**@brief return the internal system.
      *
      * Should be called after init.
@@ -62,6 +74,7 @@ class GUI : public UI {
     void Init(chrono::ChSystem*, const char* title) override;
     void SetCamera(double x, double y, double z, double dirx, double diry, double dirz) override;
     bool IsRunning(double timestep) override;
+    void SetWaveModel(std::shared_ptr<WaveBase> wave) override;
 
   private:
     std::shared_ptr<hydroc::gui::GUIImpl> pImpl;

src/gui/guihelper.cpp

@@ -1,6 +1,7 @@
 #include <hydroc/config.h>
 #include <hydroc/gui/guihelper.h>
 #include <hydroc/logging.h>
+#include <hydroc/waves/wave_base.h>
 
 #include "guihelper_impl.h"
 
@@ -28,6 +29,11 @@ bool UI::IsRunning(double timestep) {
     return true;
 }
 
+void UI::SetWaveModel(std::shared_ptr<WaveBase> wave) {
+    // Default (headless) UI does not render waves.
+    (void)wave;
+}
+
 // -----------------------------------------------------------------------------
 
 GUI::GUI() {
@@ -54,3 +60,7 @@ void GUI::SetCamera(double x, double y, double z, double dirx, double diry, doub
 bool GUI::IsRunning(double timestep) {
     return pImpl->IsRunning(timestep);
 }
+
+void GUI::SetWaveModel(std::shared_ptr<WaveBase> wave) {
+    pImpl->SetWaveModel(wave);
+}