How to move an asteroid relative to ship

Questions & Answers
1

Hello,

I have a spaceship and an asteroid. The asteroid is moving to X axis (negative value) with constant speed, let’s say 2.5, and ship is moving along X and Y axis with constant speed of 5. If the ship is moving on the same direction with the asteroid then the “speed” of the asteroid is constant, but if the ship is moving in the opposite direction, then the “speed” is increasing.
I want that the asteroid to move with constant “speed” relative to the ship.
I know that it’s something related to physics, but I don’t know how to code.
Here’s a sample gif:
109183-ezgifcom-optimize.gif

Asteroid Update Script:

void Update()
    {
        // Rotate asteroid
        float z = transform.rotation.eulerAngles.z;
        z -= speedRotation * Time.deltaTime;
        transform.rotation = Quaternion.Euler(0, 0, z);

        // Move Asteroid
        Vector3 pos = transform.position;
        pos += Vector3.left * speed * Time.deltaTime;

        transform.position = pos;
    }

Ship Update Script:

void Update ()
    {
        // Rotate Ship
        float z = transform.rotation.eulerAngles.z;
        z -= Input.GetAxis("Horizontal") * speedRotation * Time.deltaTime;
        rot = Quaternion.Euler(0, 0, z);
        transform.rotation = rot;

        // Move Ship
        Vector3 pos = transform.position;
        Vector3 velocity = new Vector3(0, Input.GetAxis("Vertical") * speed * Time.deltaTime, 0);

        pos += rot * velocity;
        transform.position = pos;

        directionX = transform.position.x - prevDirectionX;

	}

Thank you.

2

You can use Transform.Translate to translate an object in the space of another, using something in the like :

transform.Translate(x, y, z, otherTransform);