• Products
  • Solutions
  • Made with Unity
  • Learning
  • Support & Services
  • Community
  • Asset Store
  • Get Unity

UNITY ACCOUNT

You need a Unity Account to shop in the Online and Asset Stores, participate in the Unity Community and manage your license portfolio. Login Create account
  • Blog
  • Forums
  • Answers
  • Evangelists
  • User Groups
  • Beta Program
  • Advisory Panel

Navigation

  • Home
  • Products
  • Solutions
  • Made with Unity
  • Learning
  • Support & Services
  • Community
    • Blog
    • Forums
    • Answers
    • Evangelists
    • User Groups
    • Beta Program
    • Advisory Panel

Unity account

You need a Unity Account to shop in the Online and Asset Stores, participate in the Unity Community and manage your license portfolio. Login Create account

Language

  • Chinese
  • Spanish
  • Japanese
  • Korean
  • Portuguese
  • Ask a question
  • Spaces
    • Default
    • Help Room
    • META
    • Moderators
    • Topics
    • Questions
    • Users
    • Badges
  • Home /
avatar image
0
Question by Tryptex · Oct 18, 2017 at 02:41 AM · rigidbody2dspeedcheckmonitorreading

How to read the movment speed of sprite and flip basied upon it

I am trying to get an enemy to follow the player when he get's to close, but I need him to flip between left and right but my only problem is I don't know how to monitor the speed of the enemy so I don't know when to tell it to flip, can someone please help me? here is my code: I do have a rigidbody2D attached to it so you can also use that.

public class FlyingEnemy : MonoBehaviour {

 private PlayerController player;

 public float moveSpeed;

 public float playerRange;

 public GameObject deathAffect;

 public int pointsOnDeath;

 public LayerMask playerLayer;

 private bool playerInRange;

 private Rigidbody2D RB;

 // Use this for initialization
 void Start ()
 {
     player = FindObjectOfType<PlayerController>();

     RB = FindObjectOfType<Rigidbody2D>();
 }
 
 // Update is called once per frame
 void Update ()
 {
     playerInRange = Physics2D.OverlapCircle(transform.position, playerRange, playerLayer);

     if (playerInRange)
     {
         transform.position = Vector3.MoveTowards(transform.position, player.transform.position, moveSpeed * Time.deltaTime);
     }

     if (RB.velocity.magnitude < 0)
     {
         transform.localScale = new Vector3(1f, 1f, 1f);
         Debug.Log("moving left");
     }

     if(RB.velocity.magnitude > 0)
     {
         transform.localScale = new Vector3(-1f, 1f, 1f);
         Debug.Log("moving right");
     }

}

Comment
Add comment
10 |3000 characters needed characters left characters exceeded
▼
  • Viewable by all users
  • Viewable by moderators
  • Viewable by moderators and the original poster
  • Advanced visibility
Viewable by all users

1 Reply

· Add your reply
  • Sort: 
avatar image
0

Answer by CptKen · Oct 18, 2017 at 04:20 AM

RB.velocity.magnitude will always return a positive number so you cannot use that to check the direction of travel instead just check the x component of the velocity.

 if(RB.velocity.x > Mathf.Epsilon)
 {
     //Moving Right
 }
 else if(RB.velocity.x < -Mathf.Epsilon)
 {
     //Moving Left
 }
 else
 {
     //Not moving left or right
 }
 

Since you are comparing floats I suggest using Mathf.Epsilon instead of 0 because it's unlikely for a float to ever == 0 exactly due to floating point errors.

Comment
Add comment · Show 1 · Share
10 |3000 characters needed characters left characters exceeded
▼
  • Viewable by all users
  • Viewable by moderators
  • Viewable by moderators and the original poster
  • Advanced visibility
Viewable by all users
avatar image Tryptex · Oct 18, 2017 at 04:53 AM 0
Share

@Cpt$$anonymous$$en O$$anonymous$$, but one weird thing about it is that it take the enemy a good 3 seconds before he flips, Is my computer slow? is there a problem with the way I'm flipping the enemy, or is there another problem? (By the way I am now using transform.localRotation = Quaternion.Euler(0, 180, 0); to flip the enemy)

Your answer

Hint: You can notify a user about this post by typing @username

Up to 2 attachments (including images) can be used with a maximum of 524.3 kB each and 1.0 MB total.

Welcome to Unity Answers

If you’re new to Unity Answers, please check our User Guide to help you navigate through our website and refer to our FAQ for more information.

Before posting, make sure to check out our Knowledge Base for commonly asked Unity questions.

Check our Moderator Guidelines if you’re a new moderator and want to work together in an effort to improve Unity Answers and support our users.

Follow this Question

Answers Answers and Comments

72 People are following this question.

avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image

Related Questions

Keeping momentum with rigid bodies. 0 Answers

Rigidbody Problems 1 Answer

Issue regarding Rigidbody2D 0 Answers

How to acquire and use WheelJoint2D jointSpeed in my own formula 0 Answers

How to get the speed of an object? 3 Answers


Enterprise
Social Q&A

Social
Subscribe on YouTube social-youtube Follow on LinkedIn social-linkedin Follow on Twitter social-twitter Follow on Facebook social-facebook Follow on Instagram social-instagram

Footer

  • Purchase
    • Products
    • Subscription
    • Asset Store
    • Unity Gear
    • Resellers
  • Education
    • Students
    • Educators
    • Certification
    • Learn
    • Center of Excellence
  • Download
    • Unity
    • Beta Program
  • Unity Labs
    • Labs
    • Publications
  • Resources
    • Learn platform
    • Community
    • Documentation
    • Unity QA
    • FAQ
    • Services Status
    • Connect
  • About Unity
    • About Us
    • Blog
    • Events
    • Careers
    • Contact
    • Press
    • Partners
    • Affiliates
    • Security
Copyright © 2020 Unity Technologies
  • Legal
  • Privacy Policy
  • Cookies
  • Do Not Sell My Personal Information
  • Cookies Settings
"Unity", Unity logos, and other Unity trademarks are trademarks or registered trademarks of Unity Technologies or its affiliates in the U.S. and elsewhere (more info here). Other names or brands are trademarks of their respective owners.
  • Anonymous
  • Sign in
  • Create
  • Ask a question
  • Spaces
  • Default
  • Help Room
  • META
  • Moderators
  • Explore
  • Topics
  • Questions
  • Users
  • Badges