Add Layered Portraits

[CakeVR]

Adds support for layered portraits to Dialogic.

If you want to get started trying this Pull Request, take a look at this WIP doc page: https://github.com/dialogic-godot/documentation/blob/38df52f0e6d0ba19ebd1705aa13a4d4a7553952e/documentation/layered-portrait.md

Here is the new command syntax available, we need to instruct layer changes via extra_data shortcode parameters.

# Show an entire group:
show Group1

# Show a layer, does not hide others:
show Group1/Layer1

# Hide a group:
hide Group1

# Hide a layer:
hide Group1/Layer1

# Show only one layer and hide the others:
set Group1/Layer1

Examples in the timeline:

join princess (default) 2 [animation="Heartbeat" extra_data="show Group1"]

update princess [extra_data="set Group1/Layer1"]]

The syntax after the command names (hide, show, set) is based on the valid syntax for node hierarchy paths. The different commands can be executed in a single extra_data by using the , (comma) delimiter.

update princess [extra_data="set Group1/Layer1, set Group2/Layer3"]]

You can access this node path syntax by right-clicking the target group/layer and clicking Copy Node Path. However, it's a very simple syntax to learn.

Technical Details

This pull requests fixes the update event variant and allows it to set the extra data.

It also corrects the behaviour of the Portrait subsystem. Adding support to properly fade portraits in and out.

Fade Animations doing XYZ In and XYZ Out were unified as XYZ In Out, using the is_reversed (POV: Fade In) member on the base.

guess_special_resource supports searching for these In Out animations by just declaring In Out.

Leaving Animations are automatically set to be is_reversed true.

The Animation Base provides get_modulation_property as method, to easily access the correct modulation property on CanvasGroups. self_modulate affects the entire internal viewport image instead of individual parented nodes.

The Portrait Settings Tab supports a default Transition Animation. If using the Change event on unique scenes (e.g. two Layered Portraits), it will automatically resort to this animation.

[CakeVR]

This Pull Request is ready for review.

However, I have not changed all animations yet.

[Jowan-Spooner]

Alright, let's do this.