如何将键盘转换为触控器

Question

Good day i'm new to unity c#. Does anyone know how to convert my 2d top down car controller script from keyboard to touch buttons. I need to have a touch buttons that has break,back,accelerate and left right buttons for my 2d topdown car.

What my codes is based on an Arcade style car game.

    float speedForce = 15f;
    float torqueForce = -200f;
    float driftFactorSticky = 0.9f;
    float driftFactorSlippy = 1;
    float maxStickyVelocity = 2.5f;
    float minSlippyVelocity = 1.5f; // <--- Exercise for the viewer

    // Use this for initialization
    void Start () 
    {

    }

    void Update() 
    {
        // check for button up/down here, then set a bool that you will use in FixedUpdate
    }

    // Update is called once per frame
    void FixedUpdate () 
    {
        Rigidbody2D rb = GetComponent<Rigidbody2D>();

        Debug.Log(RightVelocity().magnitude);

        float driftFactor = driftFactorSticky;
        if(RightVelocity().magnitude > maxStickyVelocity) {
            driftFactor = driftFactorSlippy;
        }

        rb.velocity = ForwardVelocity() + RightVelocity()*driftFactor;

        if(Input.GetButton("Accelerate")) {
            rb.AddForce( transform.up * speedForce );

            // Consider using rb.AddForceAtPosition to apply force twice, at the position
            // of the rear tires/tyres
        }
        if(Input.GetButton("Brakes")) {
            rb.AddForce( transform.up * -speedForce/2f );

            // Consider using rb.AddForceAtPosition to apply force twice, at the position
            // of the rear tires/tyres
        }

        // If you are using positional wheels in your physics, then you probably
        // instead of adding angular momentum or torque, you'll instead want
        // to add left/right Force at the position of the two front tire/types
        // proportional to your current forward speed (you are converting some
        // forward speed into sideway force)
        float tf = Mathf.Lerp(0, torqueForce, rb.velocity.magnitude / 2);
        rb.angularVelocity = Input.GetAxis("Horizontal") * tf;
    }

    Vector2 ForwardVelocity() 
    {
        return transform.up * Vector2.Dot( GetComponent<Rigidbody2D>().velocity, transform.up );
    }

    Vector2 RightVelocity() 
    {
        return transform.right * Vector2.Dot( GetComponent<Rigidbody2D>().velocity, transform.right );
    }
}

Answer 1

instead of

if(Input.GetButton("Accelerate")) 
{
    rb.AddForce( transform.up * speedForce );
}
if(Input.GetButton("Brakes")) 
{
    rb.AddForce( transform.up * -speedForce/2f );
}

and

rb.angularVelocity = Input.GetAxis("Horizontal") * tf;

simply check for some bools instead and have according setter methods for them (You need those to be able to call them by UnityEvents):

private bool acceleratePressed;
private bool brakePressed;
private bool leftPressed;
private bool rightPressed;

public void SetAccelerate(bool pressed)
{
    acceleratePressed = pressed;
}

public void SetBrake(bool pressed)
{
    brakePressed = pressed;
}

public void SetRightPressed(bool pressed)
{
    rightPressed = pressed;
}

public void SetLeftPressed(bool pressed)
{
    leftPressed = pressed;
}

private void FixedUpdate()
{
    if(acceleratePressed) 
    {
        rb.AddForce( transform.up * speedForce );
    }
    if(brakePressed)
    {
        rb.AddForce( transform.up * -speedForce/2f );
    }

    var leftRight = 0;
    if(leftPressed && !rightPressed)
    {
        leftRight = -1;
    }
    else if(!leftPressed && rightPressed)
    {
        leftRight = 1;
    }

    // If you are using positional wheels in your physics, then you probably
    // instead of adding angular momentum or torque, you'll instead want
    // to add left/right Force at the position of the two front tire/types
    // proportional to your current forward speed (you are converting some
    // forward speed into sideway force)
    float tf = Mathf.Lerp(0, torqueForce, rb.velocity.magnitude / 2);
    rb.angularVelocity = leftRight * tf;
}

Unfortunately the Unity UI.Button doesn't have a way for forwarding button down or up .. only the onClick .

But you can very easily implement additional events on your own! You can use the IPointerDownHandler and IPointerUpHandler & IPointerExitHandler interfaces and custom UnityEvents

I don't like do inherit from UI.Button (some poeple might prefer that) but instead rather add additional behaviour in a seperate component.

There are other ways how to implement it exactly but I like to keep things reusable so I would use it like

[RequireComponent((typeof(Button)))]
public class DownUpButtonEnhancement : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler
{
    private Button _button;

    public UnityEvent OnButtonDown;
    public UnityEvent OnButtonUp;

    private void Awake()
    {
        _button = GetComponent<Button>();
    }

    //Detect current clicks on the GameObject (the one with the script attached)
    public void OnPointerDown(PointerEventData pointerEventData)
    {
        if (!_button.interactable) return;

        OnButtonDown?.Invoke();
    }

    //Detect if clicks are no longer registering
    public void OnPointerUp(PointerEventData pointerEventData)
    {
        OnButtonUp?.Invoke();
    }

    // Detect if pointer leaves the object
    public void OnPointerExit(PointerEventData eventData)
    {
        // additionally reset if pointer leaves button while pressed
        OnButtonUp?.Invoke();
    }
}

Put this on your two UI Buttons and configure the according OnButtonDown and OnButtonUp callback just the same way you would with onClick of the Button :

1. Drag in the GameObject with your movement script in
2. Select the according method that should be called every frame the button is pressed.
3. For OnButtonDown pass in true (check the box) for OnButtonUp pass in false.

Then in the game you can see that now the according bool of the MoveController script is enabled while the button is pressed and additionally reset if the pinter leaves the button while pressed