How to change collisionPolygon shape using set_deferred?

Question

I'm trying to change my CollisionPolygon2D shape via code as such:

...

self.polygon[0].x+=100

but it gives the error:

area_set_shape_disabled: Can't change this state while flushing queries. Use call_deferred() or set_deferred() to change monitoring state instead.

which is why I'm assuming I'll need to use set_deferred() to change the shape
so how do I achieve this?

Answer 1

It may be useful to use this pattern:

1. Get a copy of the value
2. Modify the temporary value
3. Set the value back

var temp_polygon = get_polygon()
temp_polygon[0].x -= 100
call_deferred("set_polygon", temp_polygon)

call_deferred is a function that calls functions by name. Here the name was "set_polygon" and the second argument is the argument for set_polygon. It calls the function later in order to avoid conflicts like this. I would prefer call_deferred over set_deferred because the setter function is less likely to cause problems as well.

As a final note, try to avoid directly accessing properties, and use the setter and getter functions when possible.