如何将弹丸射向玩家所面对的方向？

Question

I am creating a 2D side-scroller video game in Unity using c#. I have created the script that makes the player face the direction that the arrow key that was pressed was pointing to (when the right arrow is pressed, the player faces right. When the left arrow is pressed, the player faces left).

However, I cannot figure out how to make the harpoon that the player shoots point in the direction the player is facing. I have found many questions on Stack Overflow asking questions like this, but none of their answers worked for me.

Can anyone please tell me how to make the harpoon the player shoots face the direction the player is facing? Thanks in advance!

Here is my code that I use- PLAYER SCRIPT

using UnityEngine;
using System.Collections;

public class playerMove : MonoBehaviour {

// All Variables
public float speed = 10;
private Rigidbody2D rigidBody2D;
private GameObject harpoon_00001;
private bool facingRight = true;

void Awake () {

    rigidBody2D = GetComponent<Rigidbody2D>();
    harpoon_00001 = GameObject.Find("harpoon_00001");

}

void Update () {

if (Input.GetKeyDown(KeyCode.LeftArrow) && !facingRight) {
    Flip();
}

if (Input.GetKeyDown(KeyCode.RightArrow) && facingRight) {
    Flip();
}

}

void Flip () {

facingRight = !facingRight;

Vector3 theScale = transform.localScale;
theScale.x *= -1;
transform.localScale = theScale;

}

void FixedUpdate () {
    float xMove = Input.GetAxis("Horizontal");
    float yMove = Input.GetAxis("Vertical");

    float xSpeed = xMove * speed;
    float ySpeed = yMove * speed;

    Vector2 newVelocity = new Vector2(xSpeed, ySpeed);

    rigidBody2D.velocity = newVelocity;

    if (Input.GetKeyDown("space")) {
        GetComponent<AudioSource>().Play();
    Instantiate(harpoon_00001,transform.position,transform.rotation);

}

} 
}

HARPOON SCRIPT

using UnityEngine;
using System.Collections;

public class harpoonScript : MonoBehaviour {

// Public variable 
public int speed = 6;
private Rigidbody2D r2d;

// Function called once when the bullet is created
void Start () {
// Get the rigidbody component
r2d = GetComponent<Rigidbody2D>();

// Make the bullet move upward
float ySpeed = 0;
float xSpeed = -8;

Vector2 newVelocity = new Vector2(xSpeed, ySpeed);
r2d.velocity = newVelocity;

}

void Update () {

if (Input.GetKeyDown(KeyCode.LeftArrow)) {
    float xSpeed = -8;
}

if (Input.GetKeyDown(KeyCode.RightArrow)) {
    float xSpeed = 8;
}

}

void OnTriggerEnter2D(Collider2D other) //hero hits side of enemy
{

        Destroy(other.gameObject.GetComponent<Collider2D>());     //Remove collider to avoid audio replaying
        other.gameObject.GetComponent<Renderer>().enabled = false;     //Make object invisible
        Destroy(other.gameObject, 0.626f); //Destroy object when     audio is done playing, destroying it before will cause the audio to stop

}

}

Answer 1

You already defining a variable facingRight to know the direction of the the player. You can use that knowledge to control the harpoon. For example:

// this line creates a new object, which has harpoonScript attached to it.
// In unity editor, you drag and drop this prefab(harpoon_00001) into right place.
// transform.position is used for the starting point of the fire. You can also add +-some_vector3 for better placement 
// Quaternion.identity means no rotation.
harpoonScript harpoon = Instantiate(harpoon_00001,transform.position, Quaternion.identity) as harpoonScript;
// Assuming harpoon prefab already facing to right
if (!facingRight) {
  // Maybe, not required
  harpoon.transform.eulerAngles = new Vector3(0f, 0f, 180f); // Face backward
  Vector3 theScale = harpoon.transform.localScale;
  theScale.y *= -1;
  harpoon.transform.localScale = theScale; // Flip on y axis
}