Here is a small utility class (encapsulated, to allow easy copy/paste) that implements get_random_point_in_polygon. You can use this with the polygon defined in NavigationRegion, Polygon2D, or CollisionPolygon2D.
I also have a pending proposal for including something like this in the Engine.
class Triangle:
var _p1 : Vector2
var _p2 : Vector2
var _p3 : Vector2
func _init(p1: Vector2, p2: Vector2, p3: Vector2) -> void:
_p1 = p1
_p2 = p2
_p3 = p3
func get_triangle_area() -> float:
return 0.5 * abs((_p1.x*(_p2.y - _p3.y)) + (_p2.x*(_p3.y - _p1.y)) + (_p3.x*(_p1.y - _p2.y)))
func get_random_point():
var a = randf()
var b = randf()
if a > b:
var c = b
b = a
a = c
return _p1 * a + _p2 * (b - a) + _p3 * (1 - b)
static func get_random_point_in_polygon(polygon: PackedVector2Array) -> Vector2:
return get_random_point_in_triangulated_polygon(polygon, Geometry2D.triangulate_polygon(polygon))
static func get_random_point_in_triangulated_polygon(polygon: PackedVector2Array, triangle_points : PackedInt32Array) -> Vector2:
var triangle_weights : PackedFloat32Array = []
var triangles : Array[Triangle] = []
var index = 0
var polygon_size = triangle_points.size()
while index < polygon_size:
var triangle = Triangle.new(polygon[triangle_points[index]], polygon[triangle_points[index + 1]], polygon[triangle_points[index + 2]])
triangles.append(triangle)
triangle_weights.append(triangle.get_triangle_area())
index += 3
## TODO: We should allow the consumer to specify their own source of randomness, if desired.
return triangles[RandomNumberGenerator.new().rand_weighted(triangle_weights)].get_random_point()