Why does adding LIBGDX "fadeIn" action to a table in a group make the whole stage fade in?

Question

I'm trying to "fadeIn" a store "screen" which is really just an invisible group. I set the group to visible=true, set the alpha to 0 and then do a "fadeIn" on the group. The problem is that the whole stage goes black (my clear screen color) and then fades back in.

storeGroup.addAction(Actions.sequence(Actions.alpha(0), Actions.fadeIn(1)));

I even went as far as to make the Table within my StoreGroup accessible and adding the action to that, but the result is the same.

storeGroup.getTable().addAction(Actions.sequence(Actions.alpha(0), Actions.fadeIn(1)));

Essentially I just want my store group to fade in over whatever is currently displaying, but the fade in seems to apply to every other actor in my Stage, not JUST the one I'm adding it to.

Any help would be greatly appreciated, I've been working on this all morning and can't figure out why the "fadeIn" is applying to everything.

Answer 1

The most likely problem is that in one of your actor's draw calls you are forgetting to reset the batch's color. This would cause alpha transparency to carry throughout your entire stage.

Make sure you always reset the batch's color at the end of a draw call where you manipulate it. Here is an example:

public void draw (Batch batch, float parentAlpha) {
    batch.setColor(this.getColor());
    // always make sure to only multiply by the parent alpha
    batch.getColor().a *= parentAlpha;

    // do your drawing

    batch.setColor(Color.WHITE); // reset the color
}

Answer 2

Same issue. It seems to be due to when the batch is flushed? Anyways basically every Actor sibling seems to also fade with it. Also will happen with any setColor as you might expect. Workaround I have done is just wrap it with a group.

Update: Actually last item in group seems to always have issue, even if wrapped. Need a flush? Or whatever resets the alpha, etc.

Update: StrongJoshua answered it. Due to having actor outside the group and needing to reset the batch color before using it.