fix: delayed animation start when switching to a new animation

[edwardvear]

The SpriteSheetAnimationState update function doesn't always update
the sprite index to match the current frame index. When changing
animations, this delays update of sprite.index until after the first
frame duration has elapsed.

To fix this, always update the sprite index to match the current frame.

[edwardvear]

To verify this issue, I printed out the state of my character each frame; whenever the state is updated, I update the Handle<SpriteSheetAnimation> to a matching animation. I local modded benimator to print out the sprite and frame indices at the end of the update function.

State: Idle
Sprite idx: 2, Frame idx: 2
State: Running
Sprite idx: 2, Frame idx: 10
State: Running
Sprite idx: 2, Frame idx: 10
State: Running
Sprite idx: 11, Frame idx: 11

You can see that even though the frame index updates to match the new animation, the sprite index is not updated until the first frame of the new animation completes. This happens regardless of whether the AnimationState is reset when changing animations.

Compared to the behavior with the proposed change:

State: Idle
Sprite idx: 1, Frame idx: 1
State: Idle
Sprite idx: 1, Frame idx: 1
State: Running
Sprite idx: 9, Frame idx: 9
State: Running
Sprite idx: 9, Frame idx: 9

[jcornaz]

Thank you for the contribution 👍

I'd prefer a unit test, rather that a manual testing procedure. I can write one if you don't know how to or don't have time.

[edwardvear]

I can put together a unit test tomorrow/over the weekend. Thanks for taking a look!

[jcornaz]

Looks good to me. Thanks 👍

[github-actions]

🎉 This issue has been resolved in version 3.6.1 🎉