godot-demo-holes/demo/assets/scripts/environment/destructable/destructable_wall.gd

@tool
class_name DestructableWall extends Node3D

enum ExtrudeDirection {
	BACK = 0, # z
	RIGHT = 1, # x
	UP = 2 # y
}

@export_category("TrechBroom Generated Values")
@export var verts2d: PackedVector2Array
@export var meshInstance3d: MeshInstance3D
@export var extrusion_direction: ExtrudeDirection
@export var depth: float = 0.1
@export var depth_position_offset: Vector3 = Vector3.ZERO

@export var edge_non_fracture: float = 0.1
@onready var parentNode = get_node("..")

var outer_polygon: PackedVector2Array
var inner_polygons: Array[PackedVector2Array]

var static_body: StaticBody3D

func _func_godot_apply_properties(entity_properties: Dictionary) -> void:
	meshInstance3d = _find_mesh_body()
	var verticies = meshInstance3d.mesh.surface_get_arrays(0)[Mesh.ARRAY_VERTEX]
	
	extrusion_direction = entity_properties["extrude_direction"]
	
	var depth_min: float
	var depth_max: float
	
	var verts_2d: PackedVector2Array = []
	if extrusion_direction == ExtrudeDirection.BACK:
		for vert in verticies:
			verts_2d.append(Vector2(vert.x, vert.y))
			
			var d = vert.z
			
			if d > depth_max:
				depth_max = d
			elif d < depth_min:
				depth_min = d
		depth = -(abs(depth_min) + abs(depth_max))
		
		depth_position_offset = -(Vector3.BACK * (depth/2))
	elif extrusion_direction == ExtrudeDirection.RIGHT:
		for vert in verticies:
			verts_2d.append(Vector2(vert.z, vert.y))
			
			var d = vert.x
			
			if d > depth_max:
				depth_max = d
			elif d < depth_min:
				depth_min = d
		depth = -(abs(depth_min) + abs(depth_max))
		
		depth_position_offset = Vector3.RIGHT * (depth/2)
	elif extrusion_direction == ExtrudeDirection.UP:
		for vert in verticies:
			verts_2d.append(Vector2(vert.x, vert.z))
			
			var d = vert.y
			
			if d > depth_max:
				depth_max = d
			elif d < depth_min:
				depth_min = d
		depth = -(abs(depth_min) + abs(depth_max))
		
		depth_position_offset = (Vector3.UP * (depth/2))
	
	var outer_boudary = Geometry2D.convex_hull(verts_2d)
	verts2d = outer_boudary

func _ready() -> void:
	if Engine.is_editor_hint():
		return
	
	outer_polygon = verts2d
	_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, extrusion_direction, depth)
	var commited_mesh = meshGenerator.commit_mesh(meshInstance3d.get_active_material(0))
	meshGenerator.free()

	
	meshInstance3d.mesh = commited_mesh
	meshInstance3d.position += depth_position_offset
	meshInstance3d.create_trimesh_collision()
	static_body = _find_static_body()

func _re_draw():
	meshInstance3d.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, extrusion_direction, depth)
	var commited_mesh = meshGenerator.commit_mesh(meshInstance3d.get_active_material(0))
	meshGenerator.free()
	
	meshInstance3d.mesh = commited_mesh
	meshInstance3d.create_trimesh_collision()
	static_body = _find_static_body()


func hit(position: Vector3):
	var cutter = Cutter.circleCutter()
	var hole_position_offset = meshInstance3d.to_local(position)
	
	var hole_vector2_offset: Vector2
	if extrusion_direction == ExtrudeDirection.BACK:
		hole_vector2_offset = Vector2(hole_position_offset.x, hole_position_offset.y)
	elif extrusion_direction == ExtrudeDirection.RIGHT:
		hole_vector2_offset = Vector2(hole_position_offset.z, hole_position_offset.y)
	elif  extrusion_direction == ExtrudeDirection.UP:
		hole_vector2_offset = Vector2(hole_position_offset.x, hole_position_offset.z)
	
	# translate the cutter
	var hole_vectors = Transform2D(0, hole_vector2_offset) * cutter
	var draw = _add_hole(hole_vectors)
	
	if draw:
		_re_draw()

func _add_hole(new_hole: PackedVector2Array) -> bool:
	var values_to_remove = []
	
	# validate that the hole is valid
	var boundary_polygon = Geometry2D.offset_polygon(outer_polygon, -edge_non_fracture)
	
	var boundary_hole = Geometry2D.intersect_polygons(new_hole, boundary_polygon[0])
	if !boundary_hole:
		return false

	var merged: PackedVector2Array = boundary_hole[0]
	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:
		inner_polygons.erase(i)
	
	inner_polygons.append(merged)
	
	return true

func _find_static_body():
	for child in meshInstance3d.get_children():
		if child is StaticBody3D:
			return child

func _find_mesh_body():
	for child in self.get_children():
		if child is MeshInstance3D:
			return child