Modifiers Plugin

Node that allows the creation of multiple chained modifiers for any node property.

The Modifiers node is useful whether there are properties that need to change in not predefined ways, plus having each change step saved so that a rollback can be easily performed.

Installation

• Copy the addons/modifiers folder in your addons folder.
• Navigate to Project -> Project Settings -> Plugin and enable the Modifiers plugin.

Features

• Define any number of property modifiers.
• Every node property and type is supported.
• Chain multiple modifiers to the same property statically or dynamically.
• Change the way two values are combined in the chain thanks to mix modes.
• Add/remove and activate/deactivate modifiers at any time.
• Modifiers (value, mix mode and active state) keyable in the AnimationPlayer node.
• Define custom mix modes for your project.
• Custom editors and inspectors to ease the use of the plugin.

Next steps

Although the plugin is functional and many things can be achieved with it, there are a few extra features I'd like to add eventually, maybe when Godot will better support plugins creation exposing more functionality to scripting languages.

See: godotengine/godot-proposals#300

• Allow the creation of any type of property modifier, not limited to a single input of the same type as the property to be modified, but allowing any type and number of inputs.
• More editor and inspector support.

Usage examples

The examples below are possible even without this plugin, but the Modifiers node allows a flexible, modular and decoupled implementation.

• Set the scale of a node combining several independent vectors:
  • Enlarge 2x your character for a limited amount of time if a power up is picked up. More than one of the same power up can be stacked, resulting in 4x, 8x ecc enlargement.
• Set an int or a float value combining several independent values:
  • Increase or decrease your character's jump power or speed based on what terrain he is walking on.
• Set a resource override to a node only when needed:
  • Override the CollisionShape of your character only when he is attacking.

How to use

Once the plugin has been enabled here's the creation and use of a Modifiers node:

https://i.imgur.com/DhLvp0f.gif.

Modifiers

• Add the Modifiers node to your scene.

• Select a target node in the Modifiers node inspector. This node will receive the influence of the modifiers you define.

• Define which property to influence selecting "Add Property" in the inspector. A new window will popup showing all the target node's available properties.

• Add a modifier to a property selecting "Add Modifier" at the bottom of each property section. A new window will popup asking you to define a name for the modifier.

• Add as much modifiers as you want.

• Reorder modifiers selecting the arrows, change mix mode, or activate/deactivate them. Each modifier takes the result of the upper modifiers and combines its value based on its mix mode.

• Key modifiers values, mix modes and active states in AnimationPlayer nodes just like any other property.

• Access the modifiers in code using:

  ModifiersNode.get("<property_name>/<modifier_name>/value")
  ModifiersNode.get("<property_name>/<modifier_name>/mix_mode")
  ModifiersNode.get("<property_name>/<modifier_name>/active")
  
  ModifiersNode.set("<property_name>/<modifier_name>/value", value)
  ModifiersNode.set("<property_name>/<modifier_name>/mix_mode", mix_mode)
  ModifiersNode.set("<property_name>/<modifier_name>/active", active)
  

  or

  ModifiersNode["<property_name>/<modifier_name>/value"]
  ModifiersNode["<property_name>/<modifier_name>/mix_mode"]
  ModifiersNode["<property_name>/<modifier_name>/active"]
  

• Create, remove and move modifiers in code using:

  # Adds a property group.
  add_property(String property_name)
  
  # Adds a property group and a modifier. <mix_mode> (Resource) and <position> are optional.
  add_modifier(String property_name, String modifier_name, Variant value, MixMode mix_mode = default_mix_mode, int position = -1)
  
  # Removes a property and all its modifiers.
  remove_property(String property_name)
  
  # Removes a specific property modifier.
  remove_modifier(String property_name, String modifier_name)
  
  # Moves the indicated modifier <shift> positions in its modifiers list. 
  move_modifier(String property_name, String modifier_name, int shift)
  
  # Moves the indicated modifiers in position <position> in its modifiers list.
  move_modifier_to(String property_name, String modifier_name, int position)
  

• Miscellaneous

  # Returns the <modifier_name> position in its list of modifiers.
  get_modifier_position(String property_name, String modifier_name)
  
  # Returns the amount of modifiers assigned to <property_name>
  get_modifiers_amount(String property_name)
  
  # Returns the list of defined properties.
  get_properties()
  
  # Returns the list of defined modifier names assigned to <property_name>
  get_modifier_names(property_name)
  

Mix Modes

Mix modes are simple Resources.

To define a custom mix mode:

• Create a new MixMode resource.

• Fill the Name (and Object Class if it's a mix mode intended to be used with resources)

• Fill the Expression needed to calculate the resulting value. The inputs are two variables, a and b. Valid expression are:

  a + b

  or

  Vector2(a.x * b.x, a.y * b.y)

• Add your new MixMode resource to one or more lists of the default_mix_modes resource you can find in the plugin folder.

• Your new mix mode will now be displayed in the modifiers inspector's dropdown button together with the default ones.