Add set_custom_interpolator() to PropertyTweener

[KoBeWi]

Closes godotengine/godot-proposals#7807
Probably solves godotengine/godot-proposals#1251

godot.windows.editor.dev.x86_64_VsCyflxhek.mp4

(see the example in the docs)

[WagnerGFX]

Would it not be better to call the method set_custom_trans()?
For the everyday user with no knowledge of the engine's inner works, this method will just be the same as a set_trans(), but injecting a custom transition calculation.

I would also suggest a few changes to the description to avoid confusing the user with the terms "easing" and "transition".

• "Allows interpolating the value with a custom transitioning function..."
• "...subject to the tweener's easing."

I also suggest adding a warning inside set_trans() for when a custom method has already been set, to warn the user that doing such a thing is unnecessary, and they should choose only one of the methods.

One final suggestion is to rename the callable custom_method to custom_trans_method for extra code clarity.

[KoBeWi]

Would it not be better to call the method set_custom_trans()?

Not sure. set_custom_method() and set_trans() can be used independently and they work together correctly. The v passed to the callback can be itself interpolated. It's probably not very useful and the results are difficult to control, but it's possible.

[WagnerGFX]

set_custom_method() and set_trans() can be used independently and they work together correctly. The v passed to the callback can be itself interpolated.

I see... I didn't notice that part as I was following the proposal text that said they would cancel each other out.
In this case, the method could currently be considered a third interpolation type that mix with transition and ease.

How about set_interpolator() or set_custom_interpolator()?
And changing the inner callable variable to interpolator_method?

Interpolator is generic, but more descriptive and also doesn't collide with transition or ease.

[KoBeWi]

Renamed.

[akien-mga]

Thanks!