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			153 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			GDScript
		
	
			
		
		
	
	
			153 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			GDScript
		
	
| @tool
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| class_name RandomizedComposite extends Composite
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| 
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| const WEIGHTS_PREFIX = "Weights/"
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| 
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| ## Sets a predicable seed
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| @export var random_seed: int = 0:
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|     set(rs):
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|         random_seed = rs
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|         if random_seed != 0:
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|             seed(random_seed)
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|         else:
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|             randomize()
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| 
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| ## Wether to use weights for every child or not.
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| @export var use_weights: bool:
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|     set(value):
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|         use_weights = value
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|         if use_weights:
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|             _update_weights(get_children())
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|             _connect_children_changing_signals()
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|         notify_property_list_changed()
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| 
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| var _weights: Dictionary
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| 
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| 
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| func _ready():
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|     _connect_children_changing_signals()
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| 
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| 
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| func _connect_children_changing_signals():
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|     if not child_entered_tree.is_connected(_on_child_entered_tree):
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|         child_entered_tree.connect(_on_child_entered_tree)
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|     
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|     if not child_exiting_tree.is_connected(_on_child_exiting_tree):
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|         child_exiting_tree.connect(_on_child_exiting_tree)
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| 
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| 
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| func get_shuffled_children() -> Array[Node]:
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|     var children_bag: Array[Node] = get_children().duplicate()
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|     if use_weights:
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|         var weights: Array[int]
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|         weights.assign(children_bag.map(func (child): return _weights[child.name]))
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|         children_bag.assign(_weighted_shuffle(children_bag, weights))
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|     else:
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|         children_bag.shuffle()
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|     return children_bag
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| 
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| 
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| ## Returns a shuffled version of a given array using the supplied array of weights. 
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| ## Think of weights as the chance of a given item being the first in the array.
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| func _weighted_shuffle(items: Array, weights: Array[int]) -> Array:
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|     if len(items) != len(weights):
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|         push_error("items and weights size mismatch: expected %d weights, got %d instead." % [len(items), len(weights)])
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|         return items
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|     
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|     # This method is based on the weighted random sampling algorithm 
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|     # by Efraimidis, Spirakis; 2005. This runs in O(n log(n)).
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|     
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|     # For each index, it will calculate random_value^(1/weight).
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|     var chance_calc = func(i): return [i, randf() ** (1.0 / weights[i])]
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|     var random_distribuition = range(len(items)).map(chance_calc)
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|     
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|     # Now we just have to order by the calculated value, descending.
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|     random_distribuition.sort_custom(func(a, b): return a[1] > b[1])
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|     
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|     return random_distribuition.map(func(dist): return items[dist[0]])
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| 
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| 
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| func _get_property_list():
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|     var properties = []
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| 
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|     if use_weights:
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|         for key in _weights.keys():
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|             properties.append({
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|                 "name": WEIGHTS_PREFIX + key,
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|                 "type": TYPE_INT,
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|                 "usage": PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_EDITOR,
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|                 "hint": PROPERTY_HINT_RANGE,
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|                 "hint_string": "1,100"
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|             })
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|         
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|     return properties
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|     
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|     
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| func _set(property: StringName, value: Variant) -> bool:
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|     if property.begins_with(WEIGHTS_PREFIX):
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|         var weight_name = property.trim_prefix(WEIGHTS_PREFIX)
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|         _weights[weight_name] = value
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|         return true
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|     
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|     return false
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| 
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| 
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| func _get(property: StringName):
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|     if property.begins_with(WEIGHTS_PREFIX):
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|         var weight_name = property.trim_prefix(WEIGHTS_PREFIX)
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|         return _weights[weight_name]
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|     
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|     return null
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| 
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| 
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| func _update_weights(children: Array[Node]) -> void:
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|     var new_weights = {}
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|     for c in children:
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|         if _weights.has(c.name):
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|             new_weights[c.name] = _weights[c.name]
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|         else:
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|             new_weights[c.name] = 1
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|     _weights = new_weights
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|     notify_property_list_changed()
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| 
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| 
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| func _on_child_entered_tree(node: Node):
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|     _update_weights(get_children())
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| 
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|     var renamed_callable = _on_child_renamed.bind(node.name, node)
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|     if not node.renamed.is_connected(renamed_callable):
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|         node.renamed.connect(renamed_callable)
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| 
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| 
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| func _on_child_exiting_tree(node: Node):
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|     var renamed_callable = _on_child_renamed.bind(node.name, node)
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|     if node.renamed.is_connected(renamed_callable):
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|         node.renamed.disconnect(renamed_callable)
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|     
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|     var children = get_children()
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|     children.erase(node)
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|     _update_weights(children)
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| 
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| 
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| func _on_child_renamed(old_name: String, renamed_child: Node):
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|     if old_name == renamed_child.name:
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|         return # No need to update the weights.
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|     
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|     # Disconnect signal with old name...
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|     renamed_child.renamed\
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|             .disconnect(_on_child_renamed.bind(old_name, renamed_child))
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|     # ...and connect with the new name.
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|     renamed_child.renamed\
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|             .connect(_on_child_renamed.bind(renamed_child.name, renamed_child))
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|     
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|     var original_weight = _weights[old_name]
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|     _weights.erase(old_name)
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|     _weights[renamed_child.name] = original_weight
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|     notify_property_list_changed()
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| 
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| 
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| func get_class_name() -> Array[StringName]:
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|     var classes := super()
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|     classes.push_back(&"RandomizedComposite")
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|     return classes
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