Cutting Holes Into Mesh

We be cutting holes :)

demo/scripts/destructable_wall.gd

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+extends Node
+
+@export var outer_polygon: PackedVector2Array
+@export var inner_polygons: Array[PackedVector2Array]
+@export var edge_non_fracture: float = 0.1
+
+@onready var camera: Camera3D = get_node("/root/Node3D/Camera3D")
+@onready var meshInstance = MeshInstance3D.new()
+@onready var parentNode = get_node("..")
+
+var depth: float:
+	set(value):
+		if value > 0:
+			depth = -value
+		depth = value
+
+var static_body: StaticBody3D
+
+func _ready() -> void:
+	assert(camera, "camera was not found")
+	assert(len(outer_polygon) > 2, "outer polygon does not meet the required length")
+	
+	camera.connect("wall_hit", _handle_hit_signal)
+	
+	self.add_child(meshInstance)
+	_draw()
+
+func _draw():
+	var vector_indexes = GeoPolyTriangulization.triangulate(outer_polygon, inner_polygons)
+	var vectors = []
+	
+	vectors.append_array(outer_polygon)
+	for ip in inner_polygons:
+		vectors.append_array(ip)
+	
+	var meshGenerator = GeoPolyMesh.new(vector_indexes, vectors)
+	var mesh = meshGenerator.commit_mesh()
+	
+	meshInstance.mesh = mesh
+	meshInstance.create_trimesh_collision()
+	static_body = _find_static_body()
+
+func _re_draw():
+	meshInstance.remove_child(static_body)
+	static_body.queue_free()
+	
+	var vector_indexes = GeoPolyTriangulization.triangulate(outer_polygon, inner_polygons)
+	var vectors = []
+	
+	vectors.append_array(outer_polygon)
+	for ip in inner_polygons:
+		vectors.append_array(ip)
+	
+	var meshGenerator = GeoPolyMesh.new(vector_indexes, vectors)
+	var mesh = meshGenerator.commit_mesh()
+	
+	meshInstance.mesh = mesh
+	meshInstance.create_trimesh_collision()
+	static_body = _find_static_body()
+
+
+func _handle_hit_signal(wall_id: int, position: Vector3, cutter: PackedVector2Array):
+	# validate that the hit was to this wall, if not return
+	if wall_id != static_body.get_instance_id():
+		return
+
+	var hole_position_offset = self.position + position
+	var hole_vector2_offset = Vector2(hole_position_offset.x, hole_position_offset.y)
+	
+	# translate the cutter
+	var hole_vectors = Transform2D(0, hole_vector2_offset) * cutter
+	
+	_add_hole(hole_vectors)
+	
+	_re_draw()
+
+func _add_hole(new_hole: PackedVector2Array):
+	var values_to_remove = []
+	
+	var merged: PackedVector2Array = new_hole
+	for index in range(len(self.inner_polygons)):
+		var result = Geometry2D.merge_polygons(merged, self.inner_polygons[index])
+		
+		if len(result) == 1:
+			merged = result[0]
+			values_to_remove.append(self.inner_polygons[index])
+		elif len(result) > 1:
+			# need to check that they have no overlapping area if they do clip
+			var overlap = Geometry2D.intersect_polygons(result[0], result[1])
+			
+			if len(overlap) != 0:
+				merged = Geometry2D.clip_polygons(result[0], result[1])[0]
+				values_to_remove.append(self.inner_polygons[index])
+	
+	for i in values_to_remove:
+		self.inner_polygons.erase(i)
+	
+	inner_polygons.append(merged)
+
+func _find_static_body():
+	for child in meshInstance.get_children():
+		if child is StaticBody3D:
+			return child