main.cpp

#include <vsg/all.h>

#ifdef vsgXchange_FOUND
#    include <vsgXchange/all.h>
#endif

#include <QtWidgets/QApplication>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QMdiArea>

#include <vsgQt6/Window.h>

#include <iostream>

class MultiViewArea : public QMdiArea
{
public:

    vsg::ref_ptr<vsg::WindowTraits> traits;
    vsg::ref_ptr<vsgQt6::Viewer> viewer;

    MultiViewArea(QWidget *parent = nullptr) :
        QMdiArea(parent),
        viewer(vsgQt6::Viewer::create())
    {
        viewer->addEventHandler(vsg::CloseHandler::create(viewer));
    }

    struct ViewWindow
    {
        vsgQt6::Window* window = nullptr;
    };

    using Views = std::vector<ViewWindow>;
    Views views;

    size_t addView(vsg::ref_ptr<vsg::Node> vsg_scene, const QString& title = {})
    {
        auto window = new vsgQt6::Window(viewer, traits);

        auto widget = QWidget::createWindowContainer(window, this);
        widget->setWindowTitle(title);

        addSubWindow(widget);

        if (views.empty()) widget->showMaximized();
        else tileSubWindows();

        window->initializeWindow();

        // if this is the first window to be created, use its device for future window creation.
        if (!traits->device) traits->device = window->windowAdapter->getOrCreateDevice();

        // compute the bounds of the scene graph to help position camera
        vsg::ComputeBounds computeBounds;
        vsg_scene->accept(computeBounds);
        vsg::dvec3 centre = (computeBounds.bounds.min + computeBounds.bounds.max) * 0.5;
        double radius = vsg::length(computeBounds.bounds.max - computeBounds.bounds.min) * 0.6;
        double nearFarRatio = 0.001;

        uint32_t width = window->traits->width;
        uint32_t height = window->traits->height;

        vsg::ref_ptr<vsg::EllipsoidModel> ellipsoidModel(vsg_scene->getObject<vsg::EllipsoidModel>("EllipsoidModel"));
        vsg::ref_ptr<vsg::Camera> camera;
        {
            // set up the camera
            auto lookAt = vsg::LookAt::create(centre + vsg::dvec3(0.0, -radius * 3.5, 0.0), centre, vsg::dvec3(0.0, 0.0, 1.0));

            vsg::ref_ptr<vsg::ProjectionMatrix> perspective;
            if (ellipsoidModel)
            {
                perspective = vsg::EllipsoidPerspective::create(
                    lookAt, ellipsoidModel, 30.0,
                    static_cast<double>(width) /
                        static_cast<double>(height),
                    nearFarRatio, false);
            }
            else
            {
                perspective = vsg::Perspective::create(
                    30.0,
                    static_cast<double>(width) /
                        static_cast<double>(height),
                    nearFarRatio * radius, radius * 4.5);
            }

            camera = vsg::Camera::create(perspective, lookAt, vsg::ViewportState::create(VkExtent2D{width, height}));
        }

        auto trackball = vsg::Trackball::create(camera, ellipsoidModel);
        trackball->addWindow(*window);

        viewer->addEventHandler(trackball);

        auto commandGraph = vsg::createCommandGraphForView(*window, camera, vsg_scene);

        viewer->addRecordAndSubmitTaskAndPresentation({commandGraph});

        views.push_back(ViewWindow{window});

        return views.size()-1;
    }
};


int main(int argc, char* argv[])
{
    QApplication application(argc, argv);

    vsg::CommandLine arguments(&argc, argv);

    // set up vsg::Options to pass in filepaths, ReaderWriters and other IO
    // related options to use when reading and writing files.
    auto options = vsg::Options::create();
    options->fileCache = vsg::getEnv("VSG_FILE_CACHE");
    options->paths = vsg::getEnvPaths("VSG_FILE_PATH");
#ifdef vsgXchange_FOUND
    options->add(vsgXchange::all::create());
#endif

    arguments.read(options);

    auto windowTraits = vsg::WindowTraits::create();
    windowTraits->windowTitle = "vsgQt6 viewer";
    windowTraits->debugLayer = arguments.read({"--debug", "-d"});
    windowTraits->apiDumpLayer = arguments.read({"--api", "-a"});
    arguments.read("--samples", windowTraits->samples);
    arguments.read({"--window", "-w"}, windowTraits->width, windowTraits->height);
    if (arguments.read({"--fullscreen", "--fs"})) windowTraits->fullscreen = true;

    bool continuousUpdate = !arguments.read({"--event-driven", "--ed"});
    auto interval = arguments.value<int>(8, "--interval");

    if (arguments.errors())
        return arguments.writeErrorMessages(std::cerr);

    if (argc <= 1)
    {
        std::cout << "Please specify a 3d model or image file on the command line."
                  << std::endl;
        return 1;
    }

    vsg::Path filename = arguments[1];

    auto vsg_scene = vsg::read_cast<vsg::Node>(filename, options);
    if (!vsg_scene)
    {
        std::cout << "Failed to load a valid scene graph. Please specify a valid 3d "
                     "model or image file on the command line."
                  << std::endl;
        return 1;
    }

    QMainWindow* mainWindow = new QMainWindow();

    auto mdiArea = new MultiViewArea(mainWindow);

    mainWindow->setCentralWidget(mdiArea);

    mdiArea->traits = windowTraits;

    mdiArea->setContextMenuPolicy(Qt::PreventContextMenu);
    mdiArea->setViewMode(QMdiArea::ViewMode::SubWindowView);
    mdiArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    mdiArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    mdiArea->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

    mdiArea->addView(vsg_scene, "First Window");
    mdiArea->addView(vsg_scene, "Second Window");
    mdiArea->addView(vsg_scene, "Third Window");

    mdiArea->viewer->compile();

    if (interval >= 0) mdiArea->viewer->setInterval(interval);
    mdiArea->viewer->continuousUpdate = continuousUpdate;

    mainWindow->show();

    return application.exec();
}