# Engine improvements - Spine improvements, dragging demo, package formats

**URL:** https://forum.castle-engine.io/t/engine-improvements-spine-improvements-dragging-demo-package-formats/103
**Category:** News
**Created:** [November 24, 2019, 6:56pm UTC](https://forum.castle-engine.io/t/engine-improvements-spine-improvements-dragging-demo-package-formats/103 "2019-11-24T18:56:11Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![michalis](https://forum.castle-engine.io/user_avatar/forum.castle-engine.io/michalis/32/3_2.png) [@michalis](https://forum.castle-engine.io/u/michalis)
#### Post date: [November 24, 2019, 6:56pm UTC](https://forum.castle-engine.io/t/engine-improvements-spine-improvements-dragging-demo-package-formats/103/1 "2019-11-24T18:56:11Z")

</div>

| [![The Unholy Society - sister talk](https://castle-engine.io/wp/wp-content/uploads/2019/11/75627408_1948338125311995_3113513825429618688_o-200x200.jpg)](https://castle-engine.io/wp/wp-content/uploads/2019/11/75627408_1948338125311995_3113513825429618688_o.jpg "The Unholy Society - sister talk") |

We were incredibly busy lately, preparing the release of [The Unholy Society](https://unholy-society.com/) for PC (Windows, Linux) and Nintendo Switch. It’s a game by [Cat-astrophe Games](https://cat-astrophe-games.com/), using _Castle Game Engine_, programming by two of CGE developers — _Michalis Kamburelis_ and _Eugene Loza_. Check out our trailer and game information on [the game page](https://unholy-society.com/) and [wishlist us on Steam!](https://store.steampowered.com/app/746750/The_Unholy_Society/).

In the meantime, we have a number of improvements to the engine from November:

- We have exposed methods to perform “mouse look”. They can be used to make mouse dragging without being constrained by window borders. New demo of both dragging methods is available in [examples/2d\_standard\_ui/dragging\_test](https://github.com/castle-engine/castle-engine/tree/master/examples/2d_standard_ui/dragging_test).

- We support a new Spine feature to export a _single atlas for multiple skeletons_. It’s quite cool, often allows to significantly reduce the total necessary atlas sizes. To use it, you need to open Spine file through an URL like this: `my_animation.json#atlas:my_atlas_name` instead of just `my_animation.json`. See our [Spine](https://github.com/castle-engine/castle-engine/wiki/Spine) documentation for details.

- New [OrientationInterpolation2D](https://castle-engine.io/apidoc-unstable/html/X3DNodes.TOrientationInterpolator2DNode.html) allows more efficient 2D rotation interpolation. It is automatically used by Spine animations.

- [Our build tool](https://github.com/castle-engine/castle-engine/wiki/Build-Tool) allows to configure package format by `--package-format` option (allowed values for now are: default, directory, zip, targz). You can also configure whether version number appears in the resulting filename by `--package-name-no-version` option.

- Programs using `Application.ParseStandardParameters` will now automatically handle the `--log-file` command-line option, that allows the user the configure output log file. Note that, in order to make this work, you should not call `InitializeLog` before command-line options are parsed. Our examples, like [portable\_game\_skeleton](https://github.com/castle-engine/castle-engine/tree/master/examples/portable_game_skeleton), show how to do this.

- The default sound “importance” is now 10, instead of “maximum”. This seems much more reasonable. See our [new docs of sounds XML files](https://castle-engine.io/creating_data_sound.php).