GodotComponentTest/components/GroundMotionComponent.cs

using System;
using System.Numerics;
using Godot;
using Vector2 = Godot.Vector2;
using Vector3 = Godot.Vector3;

/// <summary>
/// </summary>
public class GroundMotionComponent
{
    public float Accel = 50;
    public float Damping = 0.2f;
    public float MaxSpeed = 2;

    public void PhysicsProcess(float delta, Entity entity, Vector3 target_position)
    {
        Vector2 plane_target_vector = new Vector2(target_position.x - entity.GlobalTranslation.x,
            target_position.z - entity.GlobalTranslation.z);
        float distance_error = plane_target_vector.Length();

        if (distance_error < 0.01)
        {
            entity.Velocity = Vector3.Zero;
        } else {
            Vector2 plane_velocity = new Vector2(entity.Velocity.x, entity.Velocity.z);
            plane_velocity = plane_velocity + plane_target_vector / distance_error * Accel * delta;

            float projected_step = plane_target_vector.Dot(plane_velocity * delta);
            GD.Print("Projected step: " + projected_step);
            if (projected_step > 1)
            {
                plane_velocity /= projected_step;
            }

            float plane_speed = plane_velocity.Length();
            if (plane_speed > MaxSpeed)
            {
                plane_velocity *= MaxSpeed / plane_speed;
            }

            entity.Velocity = new Vector3(
                plane_velocity.x, 0, plane_velocity.y);
        }

        entity.Velocity.x -= entity.Velocity.x * Damping;
        entity.Velocity.z -= entity.Velocity.z * Damping;
        entity.Velocity = entity.MoveAndSlide(entity.Velocity);
    }
}