Method Update

Source/Engine/Navigation/NavMeshBuilder.cpp:1159–1219

}

void NavMeshBuilder::Update()
{
    PROFILE_MEM(NavigationBuilding);
    ScopeLock lock(NavBuildQueueLocker);

    // Process nav mesh building requests and kick the tasks
    const auto now = DateTime::NowUTC();
    bool didRebuild = false;
    for (int32 i = 0; NavBuildQueue.HasItems() && i < NavBuildQueue.Count(); i++)
    {
        auto req = NavBuildQueue.Get()[i];
        if (now - req.Time >= 0)
        {
            NavBuildQueue.RemoveAt(i--);
            Scene* scene = req.Scene.Get();
            if (!scene)
                continue;
            bool rebuild = req.DirtyBounds == BoundingBox::Empty;

            // Early out if scene has no bounds volumes to define nav mesh area
            if (scene->Navigation.Volumes.IsEmpty())
            {
                ClearNavigation(scene);
                continue;
            }

            // Check if build a custom dirty bounds or whole scene
            if (rebuild)
                req.DirtyBounds = scene->Navigation.GetNavigationBounds(); // Compute total navigation area bounds
            if (didRebuild)
                rebuild = false; // When rebuilding navmesh for multiple scenes, rebuild only the first one (other scenes will use additive update)
            else
                didRebuild = true;
            BuildDirtyBounds(scene, req.DirtyBounds, rebuild);
            NavBuildCheckMissingNavMeshes = true;
        }
    }

    // Remove unused navmeshes (when all active tasks are done)
    // TODO: ignore AutoRemoveMissingNavMeshes in game and make it editor-only?
    if (NavBuildCheckMissingNavMeshes && NavBuildTasksMaxCount == 0 && NavigationSettings::Get()->AutoRemoveMissingNavMeshes)
    {
        NavBuildCheckMissingNavMeshes = false;
        NavBuildTasksLocker.Lock();
        int32 taskCount = NavBuildTasks.Count();
        NavBuildTasksLocker.Unlock();
        if (taskCount == 0)
        {
            for (Scene* scene : Level::Scenes)
            {
                for (NavMesh* navMesh : scene->Navigation.Meshes)
                {
                    if (!navMesh->Data.Tiles.HasItems())
                    {
                        navMesh->DeleteObject();
                    }
                }
            }