Use Mobile Joystick with Unity 3d RigidBody

Questions & Answers
1

I am developing a mobile 3D app. I have a game object that has a rigid body and I move it with a joystick.

I got it to the point that I can move the object forward when I take the vertical input and rotate it when I take horizontal input from the joystick.

The problem is that when I rotate the rigid body 90 deg I would expect to use horizontal input to move the object forward or backward and rotate it with vertical joystick input. Basically I want the object to move forward where joystick is being pulled, but with the current set up I have to pull joystick upwards even if object is facing left or right sides. I hope I explained it well. If not know, please let me know, I will explain it more.

public Joystick m_Joystick;
private float m_HorizontalValue;
private float m_VerticalValue;

void Update()
{
    m_VerticalValue = m_Joystick.Vertical;
    m_HorizontalValue = m_Joystick.Horizontal;
}

// Same as update, but is used fo modifying values that are used to manipulate
// game object's physics
void FixedUpdate() 
{
    Move();
    Turn();
}

void Move()
{
    Vector3 movement = transform.forward * m_VerticalValue * m_Speed * Time.deltaTime;

    m_Rigidbody.MovePosition(m_Rigidbody.position + movement);
}

void Turn()
{
    float turn = m_HorizontalValue * m_TurnSpeed * Time.deltaTime;

    Quaternion turnRotation = Quaternion.Euler(0f, turn, 0f);

    m_Rigidbody.MoveRotation(m_Rigidbody.rotation * turnRotation); 
}

I tried checking the forward vector of my rigid body (x and z values) to inverse the movement of object when joystick is pulled into the desired direction, but it is not working well, as rigid body would stuck when x and z values of forward vector are equal. The code is not complete I was testing only two quaters of x and z coordinate system (first and second quaters).

float GetVerticalOrHorizaontalValueMovement()
{
    float xValue = m_Rigidbody.transform.forward.x;
    float zValue = m_Rigidbody.transform.forward.z;

    float auxX = Mathf.Abs(xValue);
    float auxZ = Mathf.Abs(zValue);

    if (xValue > -0.1f && zValue > -0.1f)
    {
        if (auxX <= auxZ)
            return  m_HorizontalValue;
        else if (auxX >= auxZ)
            return m_VerticalValue;
    }
    else if(xValue > -0.1f && zValue < 0.1f)
    {
        if (auxX >= auxZ)
            return m_VerticalValue;
        else if (auxX <= auxZ)
            return m_HorizontalValue;
    }

    return 0f;
}

float GetVerticalOrHorizaontalValueRotation()
{
    float xValue = m_Rigidbody.transform.forward.x;
    float zValue = m_Rigidbody.transform.forward.z;

    float auxX = Mathf.Abs(xValue);
    float auxZ = Mathf.Abs(zValue);

    if (xValue > -0.1f && zValue > -0.1f)
    {
        if(auxX <= auxZ)
            return m_VerticalValue;
        else if(auxX >= auxZ)
            return m_HorizontalValue;
    }
    else if(xValue > -0.1f && zValue < 0.1f)
    {
        if (auxX >= auxZ)
            return m_HorizontalValue;
        else if (auxX <= auxZ)
            return m_VerticalValue;
    }

    return 0f;
}

The methods will be placed instead of m_VerticalValue and m_HorizontalValue variables in Move() and Turn() methods.

I am open to any solution that would make my game object move as I want with a joystick, but I have to keep it as RigidBody because I want to apply explosive forces on it and other possible forcers. If I did not explain something properly, please let me know.

2

I wrote a small script that you might find useful. I simulated a joystick with keyboard input. Here the movement works in such a way that if the desired direction of movement coincides with the transform.forward of the player, then the player moves, otherwise the player turns to the given direction.

using UnityEngine;

public class MovementOfPlayer : MonoBehaviour
{
    Vector3 movementInput;
    Rigidbody playerRigidbody;

    void Start()
    {
        playerRigidbody = GetComponent<Rigidbody>();
        playerRigidbody.freezeRotation = true;
    }

    void FixedUpdate()
    {
        movementInput = Input.GetAxisRaw("Horizontal") * Vector3.right +
                        Input.GetAxisRaw("Vertical") * Vector3.forward;
        movementInput.Normalize();

        float y = playerRigidbody.velocity.y;

        if (movementInput != Vector3.zero)
        {
            if (transform.forward != movementInput)
            {
                transform.rotation = Quaternion.RotateTowards(transform.rotation, Quaternion.LookRotation(movementInput), Time.deltaTime * 180);

                playerRigidbody.velocity = Vector3.MoveTowards(playerRigidbody.velocity, Vector3.zero, Time.deltaTime * 30);
            }
            else
            {
                playerRigidbody.velocity = Vector3.MoveTowards(playerRigidbody.velocity, movementInput * 10, Time.deltaTime * 30);
            }
        }
        else
        {
            playerRigidbody.velocity = Vector3.MoveTowards(playerRigidbody.velocity, Vector3.zero, Time.deltaTime * 30);
        }
        Vector3 velocity = playerRigidbody.velocity;
        velocity.y = y;
        playerRigidbody.velocity = velocity;
    }
}

Just assign this script to any object with collider and rigidbody.