Reversing tile animations in TileMapLayers

[delicate igloo]

I wonder what the most practical way of having reversible tiles would be. I have an undo system in my game where turns play out backwards, so it looks off when animated tiles don't do this by default. Unfortunately animated tiles cannot be set to negative speeds, that would be all I need.

I could replace all animated tiles with AnimatedSprite2D which has the functionality I want, but I like tile batching efficiency and ease of drawing them. Is ther some way of playing tile animations in TileMapLayers backwards that I'm missing? One way I could think of would be to write a shader that maps tiles to the reverse of the animation, but that would essentially necessitate recreating the whole tile animation layer since animations have a bunch of parameters, eg. per frame speed, randomized starting times, differing numbers of frames and columns etc.

Alternatively maybe it would be easier to allow negative speeds for tile animations in the engine itself and rebuilding from source, idk(?)

[plucky apex]

I see 2 ways:

• Make new tiles in the TileSet, where the frames are just added in reverse. And then swap normal with reverse if needed.
• Or write a function to manually change the frames of whatever tile, where you loop in reverse

[delicate igloo]

1. does not work because the TileMapLayer does not expose what frame of the animation its currently in as far as I know, so there would be a visual jump from one frame to another. Correct me if I'm wrong and this is doable, but I looked into it before
2. True, that would work. Is just loses the main advantage of animated tiles and would require me to reinvent the wheel in a less efficient manner

[plucky apex]

I think writing a function to do what you want hardly falls under "reinventing the wheel with less efficiency", but okay. 🤷‍♂️
Especially since you proposed building a custom version of the Engine. 🙄