Unity beginner 3 - enemy movement control and setting of blood loss area (2D)

This article comes from learning chutianbo Teacher's notes , link b standing

After we make the map and reply to the props , We need to add an enemy to the map .

Easy movement of the enemy 1

public class EmenyController : MonoBehaviour
{
    // Set the movement speed variable 
    public float speed = 0.1f;
    // Make a statement 2d Rigid objects 
     Rigidbody2D rigidbody2D;
    //  Statement  Vector2  Object to store the current position of the enemy 
    Vector2 position;
    // Declare an initial  y  Coordinate variables 
    float initY;
    // Declare a variable for the direction of movement 
    float direction;
    // Store the variable of moving distance , Set to common , Opening up in  unity  Visit in 
    public float distance = 4;
    void Start()
    {
        //  Get the values of these objects or variables at the beginning of the game 
        rigidbody2D = GetComponent<Rigidbody2D>();
        // Get the starting position 
        position = transform.position;
        // Get start y coordinate 
        initY = position.y;
        // Set the initial moving direction 
        direction = 1.0f;
    }

    // Update is called once per frame

    private void FixedUpdate()
    {
        // Method call through rigid body movement , Put in  fixupdate In the method ,0.02 Once per second 
        MovePosition();
    }
    private void MovePosition()
    {
        if (position.y - initY < distance && direction > 0)
        {
            position.y += speed;
        }
        if (position.y - initY >= distance && direction > 0)
        {
            direction = -1.0f;
        }
        if (position.y - initY > 0 && direction < 0)
        {
            position.y -= speed;
        }
        if (position.y - initY <= 0 && direction < 0)
        {
            direction = 1.0f;
        }
        rigidbody2D.position = position;
     
    }
}

This code opens up the mobile speed , Move back and forth by determining the distance from the initial position （ Only set in y On the shaft ）; Of course x Just change the code on the axis

The second movement control （ From official website ）

public class EnemyController2 : MonoBehaviour
{
    public float speed;
    public bool vertical;
    Rigidbody2D rigidbodyroot;
    // Time to go in one direction 
    public float changeTime = 3.0f;
    // timer 
    float timer;
    // Direction 
    int direction=1;

     void Start()
    {
        rigidbodyroot = GetComponent<Rigidbody2D>();
        timer = changeTime;
    

    }
    private void Update()
    {
     
        timer -= Time.deltaTime;
        if (timer < 0)
        {
            direction = -direction;
            timer = changeTime;
        }
    }
    private void FixedUpdate()
    {
     
        Vector2 position = rigidbodyroot.position;
        if (vertical)
        {
            position.y = position.y + speed * Time.deltaTime*direction;
            
        }
        else
        {
            position.x = position.x + speed * Time.deltaTime * direction;
         
        }
        rigidbodyroot.MovePosition(position);
    }
    // Rigid body collision event 
    private void OnCollisionEnter2D(Collision2D other)
    {
        RubyController rubyController = other.gameObject.GetComponent<RubyController>();
        if (rubyController != null)
        {
            rubyController.changehealth(-1);

        }
    }
   
}

This code opens the turn back time and speed as well as the walking direction ; Control the walking distance by walking time ;
At the same time, the robot meets the protagonist ruby Time makes the protagonist lose blood ;

Add blood loss area

In the area of blood loss, we use nails as picture material , Because we want to realize that we should always receive judgment , Instead of just deciding when you encounter a trigger
So we use OnTriggerStay2D It means that each frame will trigger a trigger

        RubyController rubyController = collision.GetComponent<RubyController>();
        if (rubyController != null)
        {

            rubyController.changehealth(DamageNum);

        }

problem 1： When this area needs to be larger , Our material will be reused , Here we need to use tile material

The first thing about tiling materials , We need to go back to the material interface in sprite Mode Find below Mesh Type Use Full Rect
Then in the prefabricated part Box Collider 2D The admission Auto Tiling that will do .
problem 2： Determine the code used
unity There are three kinds of judgments in OnTriggerEnter2D OnTriggerStay2D OnTriggerExit2D It means to judge once when entering
It is determined once per frame in the trigger and once when leaving ;

The material used in this article comes from unity The store Ruby’s adventure
link unity Official website