Need help in accessing C# variables or functions through gdscript

Help Programming
,
1

Godot Version

4.3

Question

i have the following scene:
-scene (Node)
----PointsCalculator (with attached the PointsCalculator.cs script) (Node)
----PointsDrawer (with attached the PointsDrawer.gd script) (Node2D)

i am trying to generate a few (x,y) points in the C# script and use the gdscript to draw them

PointsDrawer.gd script:

extends Node2D

var points_calculator

func _ready():

points_calculator = get_node(“/root/scene/PointsCalculator”)

if points_calculator:
print(“Successfully connected to PointsCalculator”) #i get this
if points_calculator.has_method(“GetPoints”):
print(“GetPoints method exists!”)
else:
print(“GetPoints method is missing!”) #i get this
else:
print(“Failed to connect to PointsCalculator”)

print(“1”)

queue_redraw()

func _draw():
var points = points_calculator.GetPoints() #fails here with “Invalid call. Nonexistent function ‘GetPoints’ in base ‘Node (PointsCalculator.cs)’.”

for point in points:
draw_circle(point, 5, Color(1, 0, 0)) # Red color circles with radius 5

func _process(_delta):

queue_redraw()

PointsCalculator.cs script:

using Godot;
using System;
using System.Collections.Generic;

public partial class PointsCalculator : Node
{
private List Points = new List();

// Example function to calculate points (you can customize this).
public void CalculatePoints()
{
    GD.Print("3!");
    Points.Clear();
    for (int i = 0; i < 10; i++)
    {
        float x = i * 20;
        float y = (float)(50 + 30 * Mathf.Sin(i));
        Points.Add(new Vector2(x, y));
        GD.Print(i," -> ", x," - ", y);
    }
    GD.Print("4#");
}

// Public method to get the points.
public List<Vector2> GetPoints()
{
    GD.Print("GetPoints method called");
    return Points;
}

public override void _Ready()
{
    // Calculate points when the node is ready.
    CalculatePoints();
    GD.Print("2!");
    for (int i = 0; i < 10; i++)
    {
        GD.Print(i, " -> ", Points[i]);
    }
}

}

the various sanity check prints are actually called and the gdscript connects the PointsCalculator, but cant find the GetPoints Method. Even if i replace it with Points as public, the gdscript still can’t find the variable Points.

Can someone help?
thanks is advance

2

You can try with signals

1 Like
3

So, that’s the only way?
isn’t it weird that it can’t be done in a more simple way?

4

The documentation page above does provide a way to access anything from a C# script with GDScript, and vice versa, here’s the specific point in the docs:

You can even call methods with no issues at all.

5

i have read that, but in my case i can’t understand why my listings dont work

PS converting the PointsDrawer to C#, it works. But that defeats the purpose of the mixing language scripts that Godot boasts about

PS2. if i try to return a single 1D array of numbers (public Array GetPoints()), everything works well between gdscript and C#. The moment i change the type of the function to list of Vector2

(public List <Vector2> GetPoints())

the gdscript cant find it and get the error mentioned above.
Any useful insights or ideas?

6

You can use Metadata. But signals give you more controlling

7

GDScript requires types to be a Variant type which is specific to the engine. You will need to return a Godot.Collections.Array<Vector2> rather than a System.Collections.Generic.List<Vector2>. If I am not mistaken you can pass any IEnumerable type into the Godot Array contructor to create a new one containing the data from the IEnumerable, so you could return new Godot.Collections.Array<Vector2>(list_var);