Avoiding 2D top-down diagonal movement

Question

Hello Everyone,

I'm working on a 2D game and I'm trying to figure how how to prevent diagonal movement. I've succeeded in preventing the character from moving diagonally, but I have a weird issue.

When I'm moving along the x axis and input to move along the y axis, it works as intended and stops moving horizontally and starts moving vertically. However, when I'm moving along the y axis and try to move horizontally, he will just continue moving up. I'm not entirely sure what's wrong.
public class Controls : MonoBehaviour {

     public float speed = 5;
     public Rigidbody2D rb;
     public Vector2 movement;
 
     // Start is called before the first frame update
     void Start()
     {
         
     }
     // Update is called once per frame
     void Update()
     {
         movement.x = Input.GetAxisRaw("Horizontal");
         movement.y = Input.GetAxisRaw("Vertical");
 
         if (movement.y != 0)
         {
             movement.x = 0;
         }
         if (movement.x != 0)
         {
             movement.y = 0;
         }
 
     }
 
     void FixedUpdate()
     {
         rb.MovePosition(rb.position + movement * speed * Time.deltaTime);
     }
 }

Answer 1

I already answered at that question but I guess I'll rewrite it.

When your script is running, when y axis is used, you set x axis movement to zero. So, when you press a key that will change x axis, nothing happens (just you keep going on Y axis). To prevent this, you have to check what was the last Axis used by your Keys. So if it was W or S it was Y axis, and else, it was X axis. What I recommend is to check if the value of Horizontal or Vertical have changed. So:

 public class Controls : MonoBehaviour
  {
     public Vector2 movement;
  
  void Update()
     {
          float x = Input.GetAxisRaw("Horizontal");
          float y = Input.GetAxisRaw("Vertical");
  
          float lastX; //To check if current x value has changed from last
          float lastY; //To check if current y value has changed from last
  
          string LastKeyUsed = ""; //will know which axis was changed
  
          if(x!=lastX) //if current x value has changed, we set the last used axis to X and set lastX to current x value
          {
              LastKeyUsed = "X";
              lastX = x;
          }
          if(y!=lastY) //if current y value has changed, we set the last used axis to Y and set lastY to current y value
          {
              LastKeyUsed = "Y";
              lastY = y;
          }
 
          if(x != 0 && y== 0) //In case you stop using the last key and have still an other key pressed, you come back to the other key axis
          {
              LastKeyUsed = "X"
          }
          if(x == 0 && y!= 0)
          {
              LastKeyUsed = "Y"
          }
 
  
          if(LastKeyUsed == "X") //Then we check which axis was last used, and we set movement x and y value depending on the result
          {
              movement.x = x;
              movement.y = 0;
          }
          else if(LastKeyUsed == "Y")
          {
              movement.x = 0;
              movement.y = y;
          }
     }
  }

And voilà! Just keep your FixedUpdate as it is. If any help needed, im here. It might not work, but I hope you got the idea.

Answer 2

  public float moveSpeed = 5f;
     float lastX; //To check if current x value has changed from last
     float lastY; //To check if current y value has changed from last
 
     string LastKeyUsed = ""; //will know which axis was changed
 
     public Rigidbody2D rb;
     public Animator anim;
 
     Vector2 movement;
     
 
     // Update is called once per frame
     void Update()
     {
       
         
         movement.x = Input.GetAxisRaw("Horizontal");
         movement.y = Input.GetAxisRaw("Vertical");
 
 
         
         
         anim.SetFloat("Speed", movement.sqrMagnitude);
     }
 
 
 
     private void FixedUpdate()
     {
         if (movement.x > 0.01f || movement.x < -0.01f)
         {
             movement.y = 0;
             anim.SetFloat("Horizontal", movement.x);
             anim.SetFloat("Vertical", movement.y);
             rb.MovePosition(rb.position + movement * moveSpeed * Time.fixedDeltaTime);
         }
         else if ( movement.y > 0.01f || movement.y < -0.01f)
         {
             movement.x = 0;
             anim.SetFloat("Horizontal", movement.x);
             anim.SetFloat("Vertical", movement.y);
 
             rb.MovePosition(rb.position + movement * moveSpeed * Time.fixedDeltaTime);
         }
     }

Try this code!, just ignore the parts about animation if you are not using a blend tree.

Avoiding 2D top-down diagonal movement

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