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[WIP] Add plain-VSG simple visualization mode for OSWEC flap #7

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Merged
salhus merged 2 commits into from
Jul 8, 2026
Merged

[WIP] Add plain-VSG simple visualization mode for OSWEC flap #7

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985a5fc
Initial plan
Copilot Jul 8, 2026
4084a06
feat: add --simple-viz mode using plain ChVisualSystemVSG box renderer
Copilot Jul 8, 2026
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3 changes: 3 additions & 0 deletions CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -143,6 +143,9 @@ endif()
if(_demo_extra_libs OR _demo_gui_libs)
target_link_libraries(demo_vgoswec PRIVATE ${_demo_extra_libs} ${_demo_gui_libs})
endif()
if(Chrono_VSG_AVAILABLE AND TARGET Chrono::Chrono_vsg)
target_compile_definitions(demo_vgoswec PRIVATE VGOSWEC_HAVE_CHRONO_VSG=1)
endif()

if(EXISTS "${SEASTACK_SOURCE_DIR_HINT}/apps/seastack/gui/guihelper.h")
target_include_directories(demo_vgoswec PRIVATE
Expand Down
178 changes: 134 additions & 44 deletions src/demo_vgoswec.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,12 +17,18 @@
#include <gui/guihelper.h>
#endif

#include <chrono/assets/ChVisualShapeBox.h>
#include <chrono/physics/ChBodyEasy.h>
#include <chrono/physics/ChLinkLock.h>
#include <chrono/physics/ChLinkMate.h>
#include <chrono/physics/ChLinkRSDA.h>
#include <chrono/physics/ChSystemNSC.h>

#ifdef VGOSWEC_HAVE_CHRONO_VSG
#include <chrono_vsg/ChVisualSystemVSG.h>
using namespace chrono::vsg3d;
#endif

#include <cmath>
#include <filesystem>
#include <fstream>
Expand All @@ -43,14 +49,16 @@ struct CLIArgs {
std::string controller_override;
std::string data_dir{"."};
bool visualization_on{true};
bool simple_viz{false};
double duration_override{-1.0};
};

static void PrintUsage(const char* argv0) {
std::cout << "Usage: " << argv0 << " --config <path.yaml> [OPTIONS]\n"
<< " --controller <name> passive|opt_passive|cc|exc_ff_pid\n"
<< " --data-dir <path>\n"
<< " --no-viz\n"
<< " --no-viz Headless (no window); takes precedence over --simple-viz\n"
<< " --simple-viz Render flap as a box via plain Chrono VSG (no SEA-Stack water surface)\n"
<< " --duration <s>\n";
}

Expand All @@ -69,6 +77,8 @@ static CLIArgs ParseCLI(int argc, char* argv[]) {
args.data_dir = argv[++i];
} else if (a == "--no-viz") {
args.visualization_on = false;
} else if (a == "--simple-viz") {
args.simple_viz = true;
} else if (a == "--duration" && i + 1 < argc) {
args.duration_override = std::stod(argv[++i]);
} else {
Expand Down Expand Up @@ -233,23 +243,43 @@ int main(int argc, char* argv[]) {
rsda->RegisterTorqueFunctor(std::make_shared<vgoswec::RsdaPtoFunctor>(controller));
system.AddLink(rsda);

// Determine which visualization path to use.
// use_simple_viz is true when:
// - the user explicitly requested --simple-viz, OR
// - visualization is on but the SEA-Stack guihelper is not available (automatic fallback).
#ifdef VGOSWEC_HAVE_SEASTACK_GUIHELPER
constexpr bool have_guihelper = true;
#else
constexpr bool have_guihelper = false;
#endif
const bool use_simple_viz =
args.simple_viz ||
(args.visualization_on && !have_guihelper);

// Attach box visual shapes for the plain-VSG renderer. These are visual-only:
// no mass, inertia, or collision geometry is added. Only added when the
// simple-viz path will be used to avoid changing the guihelper path's appearance.
if (use_simple_viz) {
// Flap: thin plate (~0.02 m × 0.30 m × 0.30 m). Thin along local X so the
// plate face is visible as the flap swings about the hinge (world Y).
auto flap_box = chrono_types::make_shared<ChVisualShapeBox>(0.02, 0.30, 0.30);
flap_box->SetColor(ChColor(0.2f, 0.5f, 0.8f));
flap_body->AddVisualShape(flap_box);

// Base/hinge marker: small cube at the base body CoG to help orient the view.
auto base_box = chrono_types::make_shared<ChVisualShapeBox>(0.05, 0.05, 0.05);
base_box->SetColor(ChColor(0.6f, 0.6f, 0.6f));
base_body->AddVisualShape(base_box);
}

std::vector<Record> records;
records.reserve(static_cast<size_t>(sim_duration / cfg.timestep) + 100);

const double dt = cfg.timestep;

#ifdef VGOSWEC_HAVE_SEASTACK_GUIHELPER
// GUI path: CreateUI(true) -> real VSG renderer; CreateUI(false) -> headless no-op.
// A single loop driven by ui.IsRunning() works for both visual and headless runs.
auto pui = seastack::viz::CreateUI(args.visualization_on);
seastack::viz::UI& ui = *pui;
ui.Init(&system, "VGOSWEC-45");
ui.SetCamera(0, -3.0, 0.5, 0, 0, -0.5);
ui.SetWaveModel(waves);

while (system.GetChTime() <= sim_duration) {
if (!ui.IsRunning(dt)) break;
if (ui.simulationStarted) {
if (!args.visualization_on) {
// ── Headless loop ────────────────────────────────────────────────────────
while (system.GetChTime() <= sim_duration) {
system.DoStepDynamics(dt);

const auto& per_comp = hydro_system.GetLastComponentForces();
Expand All @@ -275,42 +305,102 @@ int main(int argc, char* argv[]) {
records.push_back(
{system.GetChTime(), pitch_rad, pitch_vel, pto_tau, exc_tau, -pto_tau * pitch_vel});
}
}
} else if (use_simple_viz) {
// ── Simple plain-VSG box renderer (no SEA-Stack water surface) ───────────
// Uses ChVisualSystemVSG directly, mirroring Chrono's demo_VSG_shapes and the
// HIL chrono_flap_node init_visualization()/run() pattern. Avoids the
// VertexIndexDraw::record() segfault that occurs when the animated water
// surface mesh is added after Initialize() (unfixed upstream SEA-Stack bug).
#ifdef VGOSWEC_HAVE_CHRONO_VSG
auto vis = chrono_types::make_shared<ChVisualSystemVSG>();
vis->AttachSystem(&system);
vis->SetWindowTitle("VGOSWEC-45 (simple VSG)");
vis->SetWindowSize(1000, 700);
vis->AddCamera(ChVector3d(0.0, -3.0, 0.5), ChVector3d(0.0, 0.0, cfg.hinge_z + 0.3));
vis->Initialize();

while (vis->Run() && system.GetChTime() <= sim_duration) {
vis->BeginScene();
vis->Render();
vis->EndScene();

system.DoStepDynamics(dt);

const auto& per_comp = hydro_system.GetLastComponentForces();
if (!per_comp.empty()) {
exc_provider->Update(per_comp, system.GetChTime());
}

// Read all logged quantities AFTER the step so every CSV column is consistent
// at this record's timestamp (system.GetChTime()). Reading angle/velocity
// before the step previously introduced a one-timestep skew vs. torque/time.
const double pitch_rad = rsda->GetAngle();
const double pitch_vel = rsda->GetVelocity();
const double exc_tau = exc_provider->GetLatestExcitationTorque();
// GetTorque() is expected to return the applied PTO actuator torque about the
// hinge Y-axis, matching the sign of RsdaPtoFunctor/IPTOModel::ComputeForce
// and the docs/CONTROLLERS.md convention (positive torque opposes positive theta;
// P_abs = -tau*omega). Quick validation: in a `passive` run, pto_torque_nm
// should have the OPPOSITE sign to flap_pitch_vel_rads, yielding net-positive
// power_w. If it does not, negate pto_tau here (logging-only) to restore the
// documented convention.
const double pto_tau = rsda->GetTorque();

records.push_back(
{system.GetChTime(), pitch_rad, pitch_vel, pto_tau, exc_tau, -pto_tau * pitch_vel});
}
#else
std::cerr << "ERROR: --simple-viz requested but this build does not include Chrono VSG.\n"
<< "Rebuild with Chrono VSG support or use --no-viz.\n";
return 2;
#endif
} else {
// ── SEA-Stack guihelper path (unchanged) ─────────────────────────────────
#ifdef VGOSWEC_HAVE_SEASTACK_GUIHELPER
// GUI path: CreateUI(true) -> real VSG renderer; CreateUI(false) -> headless no-op.
// A single loop driven by ui.IsRunning() works for both visual and headless runs.
auto pui = seastack::viz::CreateUI(args.visualization_on);
seastack::viz::UI& ui = *pui;
ui.Init(&system, "VGOSWEC-45");
ui.SetCamera(0, -3.0, 0.5, 0, 0, -0.5);
ui.SetWaveModel(waves);

while (system.GetChTime() <= sim_duration) {
if (!ui.IsRunning(dt)) break;
if (ui.simulationStarted) {
system.DoStepDynamics(dt);

const auto& per_comp = hydro_system.GetLastComponentForces();
if (!per_comp.empty()) {
exc_provider->Update(per_comp, system.GetChTime());
}

// Read all logged quantities AFTER the step so every CSV column is consistent
// at this record's timestamp (system.GetChTime()). Reading angle/velocity
// before the step previously introduced a one-timestep skew vs. torque/time.
const double pitch_rad = rsda->GetAngle();
const double pitch_vel = rsda->GetVelocity();
const double exc_tau = exc_provider->GetLatestExcitationTorque();
// GetTorque() is expected to return the applied PTO actuator torque about the
// hinge Y-axis, matching the sign of RsdaPtoFunctor/IPTOModel::ComputeForce
// and the docs/CONTROLLERS.md convention (positive torque opposes positive theta;
// P_abs = -tau*omega). Quick validation: in a `passive` run, pto_torque_nm
// should have the OPPOSITE sign to flap_pitch_vel_rads, yielding net-positive
// power_w. If it does not, negate pto_tau here (logging-only) to restore the
// documented convention.
const double pto_tau = rsda->GetTorque();

records.push_back(
{system.GetChTime(), pitch_rad, pitch_vel, pto_tau, exc_tau, -pto_tau * pitch_vel});
}
}
#else
if (args.visualization_on) {
// Should not reach here: use_simple_viz would be true when guihelper is absent.
std::cerr << "ERROR: Visualization requested but GUI support is not available in this build.\n"
<< "Rebuild with GUI support or use --no-viz.\n";
return 2;
}

// Headless loop
while (system.GetChTime() <= sim_duration) {
system.DoStepDynamics(dt);

const auto& per_comp = hydro_system.GetLastComponentForces();
if (!per_comp.empty()) {
exc_provider->Update(per_comp, system.GetChTime());
}

// Read all logged quantities AFTER the step so every CSV column is consistent
// at this record's timestamp (system.GetChTime()). Reading angle/velocity
// before the step previously introduced a one-timestep skew vs. torque/time.
const double pitch_rad = rsda->GetAngle();
const double pitch_vel = rsda->GetVelocity();
const double exc_tau = exc_provider->GetLatestExcitationTorque();
// GetTorque() is expected to return the applied PTO actuator torque about the
// hinge Y-axis, matching the sign of RsdaPtoFunctor/IPTOModel::ComputeForce
// and the docs/CONTROLLERS.md convention (positive torque opposes positive theta;
// P_abs = -tau*omega). Quick validation: in a `passive` run, pto_torque_nm
// should have the OPPOSITE sign to flap_pitch_vel_rads, yielding net-positive
// power_w. If it does not, negate pto_tau here (logging-only) to restore the
// documented convention.
const double pto_tau = rsda->GetTorque();

records.push_back(
{system.GetChTime(), pitch_rad, pitch_vel, pto_tau, exc_tau, -pto_tau * pitch_vel});
}
#endif
}

std::filesystem::create_directories("output");
std::ofstream csv("output/vgoswec_45_results.csv");
Expand Down