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https://github.com/thiagola92/la-ik
Godot addon for inverse kinematics in 2D
https://github.com/thiagola92/la-ik
addon gdscript godot
Last synced: about 2 months ago
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Godot addon for inverse kinematics in 2D
- Host: GitHub
- URL: https://github.com/thiagola92/la-ik
- Owner: thiagola92
- License: mit
- Created: 2023-12-10T23:38:23.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2024-06-27T11:15:35.000Z (6 months ago)
- Last Synced: 2024-06-27T16:27:52.641Z (6 months ago)
- Topics: addon, gdscript, godot
- Language: GDScript
- Homepage:
- Size: 786 KB
- Stars: 9
- Watchers: 3
- Forks: 1
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# LaIK
Inverse Kinematic addon for Godot.
Here is a [short video](https://youtu.be/42IAwWF51gE) (without sound) showing how to use 3 of the inverse kinematics.
Main differences between Godot IK and this addon are:
1. There is no Node like [Skeleton2D](https://docs.godotengine.org/en/stable/classes/class_skeleton2d.html) to handle all bones.
- Why? I don't know... My plan is to wait the "need" for it.
2. Inverse kinematics are not [Resource](https://docs.godotengine.org/en/stable/classes/class_resource.html), there is a Node for each IK.
# Installation
- Download latest release
- Extract `addons` directory from ZIP
- Move `addons` directory to your project directory
- If your project already have an `addons` directory, copy `addons/la_ik` to your project `addons`
- Open Godot project
- Go to `Project > Project Settings... > Plugins`
- You should be seeing LaIK plugin there, otherwise something was done wrong
- Check `Enable` in LaIK plugin
- Restart Godot
# Good and Bad
Good:
- Scaling only one of the axis negatively works
Bad:
- Probably slower than Godot IK
- Written in GDScript
- Create [Polygon2D](https://docs.godotengine.org/en/stable/classes/class_polygon2d.html) to represent bone shapes
- Only contains logic of
- [SkeletonModification2DLookAt](https://docs.godotengine.org/en/stable/classes/class_skeletonmodification2dlookat.html)
- [SkeletonModification2DTwoBonesIK](https://docs.godotengine.org/en/stable/classes/class_skeletonmodification2dtwoboneik.html)
- [SkeletonModification2DCCDIK](https://docs.godotengine.org/en/stable/classes/class_skeletonmodification2dccdik.html)
- [SkeletonModification2DFABRIK](https://docs.godotengine.org/en/stable/classes/class_skeletonmodification2dfabrik.html)
- No integration with Godot default nodes
- Can't add skeleton to [Polygon2D.skeleton](https://docs.godotengine.org/en/stable/classes/class_polygon2d.html#class-polygon2d-property-skeleton)
# Why
(11-dez-2023) After a long time reading Godot inverse kinematic and trying to fix ([#83397][1], [#83330][2], [#81544][3], [#81051][4], [#81048][5]), I started questioning myself if my changes were correct ([comment][6]).
So I started rewriting in GDScript to get a better knowledge of the logic! The difference is that I'm copying logic that makes sense to me and removing anything that I don't understand why exists (and writing my own logic).
This could be a bad decision, but rewriting will give me a better idea of the problems and solutions that others had.
[1]: https://github.com/godotengine/godot/pull/83397
[2]: https://github.com/godotengine/godot/pull/83330
[3]: https://github.com/godotengine/godot/pull/81544
[4]: https://github.com/godotengine/godot/pull/81051
[5]: https://github.com/godotengine/godot/pull/81048
[6]: https://github.com/godotengine/godot/pull/83330#issuecomment-1809000653
# Credits
- [Godot](https://godotengine.org/).
- [TwistedTwigleg](https://github.com/godotengine/godot/pull/47872) for writing IK for Godot.
- [Alan Zucconi](https://www.alanzucconi.com/2018/05/02/ik-2d-1/) for explaining Two Bones IK.
- [Ryan Jucket](https://www.ryanjuckett.com/cyclic-coordinate-descent-in-2d/) for explaining CCDIK.
- [Sean](https://sean.cm/a/fabrik-algorithm-2d) for explaining FABRIK.