Allow separate handle modes for in and out handles on Bezier animation curves

[Arnklit]

Describe the project you are working on

A 2D game in production

Describe the problem or limitation you are having in your project

Our animators are used to tools where they have better control over the bezier curves, including the ability to have separate modes for the in and out handles on each key.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

In Blender and other animation editors you can set the mode of each handle separately, for example set the vectors between two keys to Vector to make the interpolation between them linear, but still be able to manipulate the other handles.

blender_ODS0xSYEji.mp4

This is not possible in Godot, you always set the mode for both handles.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Not certain, either you should be able to select the handles and do operations on them, like you can in Blender, or there would need to be the option to do operations to the both, left and right handles in the right click menu on a key. In that case, only the "Both Handles" would then have "Balanced" and "Mirrored" options, the "Left Handle" and "Right Handle" would only be able to be set to "Free" and "Linear".

If this enhancement will not be used often, can it be worked around with a few lines of script?

This could not be worked around in a few lines of script.

Is there a reason why this should be core and not an add-on in the asset library?

This would have to be built in as the animation resources would need to store additional data. And it's about improving the animation experience out of the box.