Episode 02

Gun System——武器系统

Player

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(PlayerController))]
[RequireComponent(typeof(GunController))]

public class Player : MonoBehaviour
{

    public float moveSpeed = 5;

    Camera viewCamera;
    PlayerController controller;
    GunController gunController;

    void Start()
    {
        controller = GetComponent<PlayerController>();
        gunController = GetComponent<GunController>();
        viewCamera = Camera.main;
    }

    void Update()
    {
        //实现Player移动
        Vector3 moveInput = new Vector3(Input.GetAxisRaw("Horizontal"), 0, Input.GetAxisRaw("Vertical"));
        Vector3 moveVelocity = moveInput.normalized * moveSpeed;
        controller.Move(moveVelocity);

        //实现Player朝向鼠标位置
        Ray ray = viewCamera.ScreenPointToRay(Input.mousePosition);
        Plane groundPlane = new Plane(Vector3.up, Vector3.zero);
        float rayDistance;

        if (groundPlane.Raycast(ray, out rayDistance))
        {
            Vector3 point = ray.GetPoint(rayDistance);
            //Debug.DrawLine(ray.origin, point, Color.red);
            //Debug.DrawRay(ray.origin,ray.direction * 100,Color.red);
            controller.LookAt(point);
        }

        //实现Gun射击
        if (Input.GetMouseButton(0))
        {
            gunController.Shoot();
        }
    }
}

[RequireComponent(typeof(需要依赖的Script))] :把一个Script绑定到GameObject上时会同时把需要依赖的脚本也一起绑定上去，优点：1.减少操作，当绑定需要的脚本的时候其所依赖的脚本也一起绑定；2.可以避免因遗漏绑定其他脚本而出错。

GetComponent():从当前游戏对象获取组件T，只在当前游戏对象中获取，没得到的就返回null，不会去子物体中去寻找。

Gun

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Gun : MonoBehaviour
{
    public Transform muzzle;
    public Projectile projectile;
    public float msBetweenShots = 100;
    public float muzzleVelocity = 35;

    float nextShotTime;

    //Shoot方法实例化Projectil
    public void Shoot()
    {
        if (Time.time > nextShotTime)
        {
            nextShotTime = Time.time + msBetweenShots / 1000;
            Projectile newProjectile = Instantiate(projectile, muzzle.position, muzzle.rotation) as Projectile;
            newProjectile.SetSpeed(muzzleVelocity);
        }
    }
}

msBetweenShots:两次射击的间隔时间（毫秒）

muzzleVelocity:子弹移动的速度，muzzleVeloc传给Projectile的SetSpeed设置

GunController

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GunController : MonoBehaviour
{
    public Transform weaponHold;
    public Gun startingGun;
    Gun equippedGun;

    void Start()
    {
        if (startingGun != null)
        {
            EquipGun(startingGun);
        }
        
    }

    //实例化Gun
    private void EquipGun(Gun gunToEquip)
    {
        if (equippedGun != null)
        {
            Destroy(equippedGun.gameObject);
        }
        equippedGun = Instantiate(gunToEquip, weaponHold.position ,weaponHold.rotation) as Gun;
        equippedGun.transform.parent = weaponHold;
    }

    //调用Gun的Shoot方法
    public void Shoot()
    {
        if (equippedGun != null)
        {
            equippedGun.Shoot();
        }
    }
}

Projectile

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Projectile : MonoBehaviour
{
    float speed = 10;

    public void SetSpeed(float newSpeed)
    {
        speed = newSpeed;
    }
    
    void Update()
    {
        //Projectile移动
        transform.Translate(Vector3.forward * Time.deltaTime * speed);
    }
}

Transform.Translate():移动，可以传入两个变量，前一个变量是物体的移动速度，这里的速度是一个矢量，既包含大小写包含方向，后一个变量是相对坐标系，这里的相对坐标系有两个值，一个是世界坐标，一个是自身坐标，如果第一个坐标不填写的话，默认为自身坐标系。

拓展：

• GetComponent<T>()详解