Method activate

plugins/cube/cube.cpp:359–394

Tries to initialize renderer, activate plugin, etc. */

    /* Tries to initialize renderer, activate plugin, etc. */
    bool activate()
    {
        if (output->is_plugin_active(grab_interface.name))
        {
            return true;
        }

        if (!output->activate_plugin(&grab_interface))
        {
            return false;
        }

        wf::get_core().connect(&on_motion_event);

        render_node = std::make_shared<cube_render_node_t>(this);
        wf::scene::add_front(wf::get_core().scene(), render_node);
        output->render->add_effect(&pre_hook, wf::OUTPUT_EFFECT_PRE);
        output->render->set_require_depth_buffer(true);

        wf::get_core().hide_cursor();
        input_grab->grab_input(wf::scene::layer::OVERLAY);

        auto wsize = output->wset()->get_workspace_grid_size();
        animation.side_angle = 2 * M_PI / float(wsize.width);
        identity_z_offset    = 0.5 / std::tan(animation.side_angle / 2);
        if (wsize.width == 1)
        {
            // tan(M_PI) is 0, so identity_z_offset is invalid
            identity_z_offset = 0.0f;
        }

        reload_background();
        animation.cube_animation.offset_z.set(identity_z_offset + Z_OFFSET_NEAR,
            identity_z_offset + Z_OFFSET_NEAR);
        return true;
    }

    int calculate_viewport_dx_from_rotation()
    {