Unity 2D move and rotate issue

Question

I am working on adding a helicopter to my 2d game and I need it to move in circular motion whilst moving on the x axis as well. Below you can find the code that I am using which uses the mathematical circle equation.

angle += speed * Time.deltaTime; //if you want to switch direction, use -= instead of +=
float x = startPoint.x + Mathf.Cos(angle) * radius;
float y = startPoint.y + Mathf.Sin(angle) * radius;
transform.position = new Vector2(x + 2, y);

The helicopter is rotating correctly but I can't figure out how I can make it move along the x axis. Concept image of how it should work below:

You probably want a parent `GameObject`moving along the X-axis with the helicopter as a child, rotating (which seems strange, but whatever). — trojanfoe, Feb 04 '20 at 20:11

score 1 · Accepted Answer · edited Feb 05 '20 at 13:58

1

1) Make an empty game object

2) Parent your box to the empty game object

3) rotate the box around the empty game object

4) move the empty game object to the side

If you want to avoid adding an empty parent, you can keep track of the center of rotation separately, rotate around it, and move it over time.

public class hello_rotate : MonoBehaviour
{
    float angle = 0;
    float radius = 1;
    float speed = 10;
    float linear_speed = 1;
    Vector2 centerOfRotation;
    // Start is called before the first frame update
    void Start()
    {
        centerOfRotation = transform.position;
    }

    // Update is called once per frame
    void Update()
    {
        centerOfRotation.x = centerOfRotation.x + linear_speed * Time.deltaTime;

        angle += speed * Time.deltaTime; //if you want to switch direction, use -= instead of +=
        float x = centerOfRotation.x + Mathf.Cos(angle) * radius;
        float y = centerOfRotation.y + Mathf.Sin(angle) * radius;
        transform.position = new Vector2(x + 2, y);
    }
}

edited Feb 05 '20 at 13:58

Matthew Scicluna

87
7

answered Feb 04 '20 at 20:11

Leo Bartkus

1,925
13
17

I thought about using this approach but is it possible to do it without using a parent game object? – Matthew Scicluna Feb 04 '20 at 20:11
You could, by keeping track of the center of rotation in its own vector2. – Leo Bartkus Feb 04 '20 at 20:14
Any chance you have an example on how to achieve this? – Matthew Scicluna Feb 04 '20 at 20:15
1

sure, I'll add it to the answer – Leo Bartkus Feb 04 '20 at 20:22
Thanks a lot mate, was nearly there haha :) – Matthew Scicluna Feb 04 '20 at 20:26

Unity 2D move and rotate issue

1 Answers1