Function renderViewThreadSafe

src/python/lfs/py_rendering.cpp:544–618

        }

        [[nodiscard]] std::optional<core::Tensor> renderViewThreadSafe(
            const glm::mat3& rotation,
            const glm::vec3& translation,
            const int width,
            const int height,
            const float fov_degrees,
            const PreviewReadback readback,
            const std::optional<glm::vec3>& background_color_override,
            const std::optional<bool> orthographic_override = std::nullopt,
            const std::optional<float> ortho_scale_override = std::nullopt) {
            auto invoke_render = [&]() -> std::optional<core::Tensor> {
                return renderViewOnViewerThread(
                    rotation,
                    translation,
                    width,
                    height,
                    fov_degrees,
                    readback,
                    background_color_override,
                    orthographic_override,
                    ortho_scale_override);
            };

            auto* const viewer = get_visualizer();
            if (!viewer || viewer->isOnViewerThread()) {
                return invoke_render();
            }
            if (!viewer->acceptsPostedWork()) {
                return std::nullopt;
            }

            auto promise = std::make_shared<std::promise<std::optional<core::Tensor>>>();
            auto future = promise->get_future();
            auto completed = std::make_shared<std::atomic_bool>(false);

            auto finish = [promise, completed](std::optional<core::Tensor> result) mutable {
                if (!completed->exchange(true)) {
                    promise->set_value(std::move(result));
                }
            };

            const bool posted = viewer->postWork(vis::Visualizer::WorkItem{
                .run =
                    [rotation,
                     translation,
                     width,
                     height,
                     fov_degrees,
                     readback,
                     background_color_override,
                     orthographic_override,
                     ortho_scale_override,
                     finish]() mutable {
                        finish(renderViewOnViewerThread(
                            rotation,
                            translation,
                            width,
                            height,