extends Node

# provides all the utility functions for generating
# a triangulized Polygon with holes
class_name GeoPolyTriangulization

# triangles are made by 3 vector
const CHUNK_RESULT: int = 3

# the boundary polygon
var _outer_polygon: PackedVector2Array

# inner polygons (holes)
var _inner_polygons: Array[PackedVector2Array]

# all vector points defined by outer and inner polygons
var vectors: PackedVector2Array = []

var _edge_safety: float = 0.0

func _init(outer_polygon: PackedVector2Array, inner_polygons: Array[PackedVector2Array], edge_safety: float):
	self._outer_polygon = outer_polygon
	self._edge_safety = edge_safety

	# calulate boundary
	var hole_boundary = Geometry2D.offset_polygon(outer_polygon, self._edge_safety)[0]
	
	for ip in inner_polygons:
		var new_hole = Geometry2D.intersect_polygons(hole_boundary, ip)[0]
		self._inner_polygons.append(new_hole)
	
	self.vectors.append_array(self._outer_polygon)
	
	for inner_polygon in self._inner_polygons:
		self.vectors.append_array(inner_polygon)

# returns all triangles generated by ear clipping the outer and inner polygons
func triangulate() -> PackedInt32Array:
	var triag = Triangulization.new()
	return triag.triangulate_with_holes(self._outer_polygon, self._inner_polygons)