一、效果图演示

二、逻辑剖析

从界面上：

• 需要一个Canvas满屏对着用户，该Canvas上展示用户的游戏数据，比如血条。
• 需要一个Canvas放在蓝色坦克上方，也需要实时对着用户，显示敌人的血条信息
• 两个坦克
• 一个平面Plane放草地的纹理

从逻辑上：

• 前后箭头键控制玩家前进或后退
• 左右箭头键控制玩家左右转向
• 鼠标左键或空格键控制玩家发射炮弹
• 玩家血条希纳是在屏幕左上角
• 相机在玩家后上方的位置，始终跟随玩家，朝玩家正前方看
• 玩家移动时，敌人转向玩家，当偏离玩家的角度小于5度时，发射炮弹
• 敌人血条显示在其上方，并且始终看向相机

三、界面组件信息

（1）游戏对象层级结构

（2）组件参数信息

1.玩家Player组件参数

Name	Type	Position	Rotation	Scale	Color
Player	Empty	(0, 0.25, -5)	(0, 0, 0)	(1, 1, 1)	#228439
Button	Cube	(0, 0, 0)	(0, 0, 0)	(2, 0.5, 2)	#228439
Top	Cube	(0, 0.5, 0)	(0, 0, 0)	(1, 0.5, 1)	#228439
Gun	Cylinder	(0, 0, 1.5)	(90, 0, 0)	(0.2, 1, 0.4)	#228439
FirePoint	Empty	(0, 1.15, 0)	(0, 0, 0)	(1, 1, 1)	--

Player 游戏对象添加了刚体组件，并修改 Mass = 100，Drag = 1，AngularDrag = 0.1，Freeze Rotation 中勾选 X 和 Z。 

2.玩家HP组件参数

Name	Type	Position	Width/Height	Color
PlayerHP	Canvas	(960, 540, 0)	1920/1080	--
Panel	Panel	位置信息全是0		#FFFFFF
HealthBG	Image	(-809,464,0)	200/20	#FFFFFF
Health	Image	(-809,464,0)	200/20	#FF2230

玩家 PlayerHP 的 Canvas 渲染模式是 Screen Space - Overlay。

制作一个红色的图片放入Health的Source Image中，Health 的 ImageType 设置为 Filled，Fill Method 设置为 Horizontal。

3.敌人组件参数

Name	Type	Position	Rotation	Scale	Color
Enemy	Empty	(0, 0.25, 5)	(0, 180, 0)	(1, 1, 1)	#15D3F9
Button	Cube	(0, 0, 0)	(0, 0, 0)	(2, 0.5, 2)	#15D3F9
Top	Cube	(0, 0.5, 0)	(0, 0, 0)	(1, 0.5, 1)	#15D3F9
Gun	Cylinder	(0, 0, 1.5)	(90, 0, 0)	(0.2, 1, 0.4)	#15D3F9
FirePoint	Empty	(0, 1.15, 0)	(0, 0, 0)	(1, 1, 1)	--

Enemy 游戏对象添加了刚体组件，并修改 Mass = 100，Drag = 0.5，AngularDrag = 0.1，Freeze Rotation 中勾选 X 和 Z。  

4.敌人HP组件参数

Name	Type	Position	Width/Height	Color
HP	Canvas	(0, 0.85, 0)	2/0.2	--
HealthBG	Image	(0,0,0)	2/0.2	#FFFFFF
Health	Image	(0,0,0)	2/0.2	#FF2230

敌人 HP 的 Canvas 渲染模式是 World Space，将刚才的红色底图也放入Health的Source Image中，Health 的 ImageType 设置为 Filled，Fill Method 设置为 Horizontal。

5.地面和炮弹的组件参数

Name	Type	Position	Rotation	Scale	Color
Plane	Plane	(0, 0, 0)	(0, 0, 0)	(10, 10, 10)	GrassRockyAlbedo
Bullet	Sphere	(0, 0.5, -5)	(0, 0, 0)	(0.3, 0.3, 0.3)	#228439

炮弹作为预设体拖拽到 Assets/Resources/Prefabs 目录下，并且添加了刚体组件。

四、脚本代码：

1.CameraController

 CameraController 脚本组件挂在 MainCamera 游戏对象上。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class CameraController : MonoBehaviour
{// Start is called before the first frame updateprivate Transform player; // 玩家private Vector3 relaPlayerPos; // 相机在玩家坐标系中的位置private float targetDistance = 15f; // 相机看向玩家前方的位置void Start(){relaPlayerPos = new Vector3(0, 4, -8);player = GameObject.Find("Player/Top").transform; // 世界坐标系位置}private void LateUpdate(){ComCameraPos();}// 计算相机坐标private void ComCameraPos(){Vector3 target = player.position + player.forward * targetDistance;transform.position = transformVecter(relaPlayerPos, player.position, player.right, player.up, player.forward);transform.rotation = Quaternion.LookRotation(target - transform.position);}// 以origin为原点，已知vec在坐标轴locX/locY/locZ中的位置，将vec转为世界坐标系的位置private Vector3 transformVecter(Vector3 vec, Vector3 origin, Vector3 locX, Vector3 locY, Vector3 locZ) { return vec.x * locX + vec.y * locY + vec.z * locZ + origin;}
}

2.BulletInfo

using UnityEngine;public class BulletInfo
{public string name; // 炮弹名public Color color; // 炮弹颜色public Vector3 flyDir; // 炮弹飞出方向public float speed; // 炮弹飞行速度public float fireRange; // 炮弹射程public BulletInfo(string name, Color color, Vector3 flyDir, float speed, float fireRange){this.name = name;this.color = color;this.flyDir = flyDir;this.speed = speed;this.fireRange = fireRange;}
}

3.BulletController

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;public class BulletController : MonoBehaviour
{private BulletInfo bulletInfo; // 炮弹信息private volatile bool isDying = false;// Start is called before the first frame updatevoid Start(){gameObject.name = bulletInfo.name;GetComponent<MeshRenderer>().material.color = bulletInfo.color;float lifeTime = bulletInfo.fireRange / bulletInfo.speed; // 存活时间Destroy(gameObject, lifeTime);}// Update is called once per framevoid Update(){transform.GetComponent<Rigidbody>().velocity = bulletInfo.flyDir * bulletInfo.speed;}public void SetBulletInfo(BulletInfo bulletInfo){this.bulletInfo = bulletInfo;}private void OnCollisionEnter(Collision other){if (isDying){return;}if(IsHitEnemy(gameObject.name, other.gameObject.name)){other.transform.Find("HP/Health").GetComponent<Image>().fillAmount -= 0.1f;isDying = true;Destroy(gameObject, 0.1f);}else if(IsHitPlayer(gameObject.name, other.gameObject.name)){GameObject.Find("PlayerHP/Panel/Health").GetComponent<Image>().fillAmount -= 0.1f;isDying = true;Destroy(gameObject, 0.1f);}}private bool IsHitEnemy(string name, string otherName){return name.Equals("PlayerBullet") && otherName.Equals("Enemy");}private bool IsHitPlayer(string name, string otherName){return name.Equals("EnemyBullet") && otherName.Equals("Player");}
}

4.PlayerController

PlayerController 脚本组件挂在 Player 游戏对象上。 

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class PlayerController : MonoBehaviour
{private Transform firePoint; // 开火点private GameObject bulletPrefab; // 炮弹预设体private float tankMoveSpeed = 4f; // 坦克移动速度private float tankRotateSpeed = 2f; // 坦克转向速度private float fireWaitTime = float.MaxValue; // 距离上次开火已等待的时间private float bulletCoolTime = 0.15f; // 炮弹冷却时间void Start(){firePoint = transform.Find("Top/Gun/FirePoint");bulletPrefab = (GameObject)Resources.Load("Prefabs/Bullet");}// Update is called once per framevoid Update(){fireWaitTime += Time.deltaTime;float hor = Input.GetAxis("Horizontal");float ver = Input.GetAxis("Vertical");Move(hor, ver);if(Input.GetMouseButtonDown(0) || Input.GetKeyDown(KeyCode.Space)){Fire();}}// 坦克移动private void Move(float hor, float ver) {if (Mathf.Abs(hor) > 0.1f || Mathf.Abs(ver) > 0.1f) {GetComponent<Rigidbody>().velocity = transform.forward * tankMoveSpeed * ver;GetComponent<Rigidbody>().angularVelocity = Vector3.up * tankRotateSpeed * hor;}}// 开炮private void Fire(){if (fireWaitTime > bulletCoolTime) { BulletInfo bulletInfo = new BulletInfo("PlayerBullet", Color.red, transform.forward, 10f, 15f);GameObject bullet = Instantiate(bulletPrefab, firePoint.position, Quaternion.identity);bullet.AddComponent<BulletController>().SetBulletInfo(bulletInfo);fireWaitTime = 0f;}}
}

5.EnemyController

EnemyController 脚本组件挂在 Enemy 游戏对象上。  

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class EnemyController : MonoBehaviour
{private Transform target; // 目标private Transform top; // 炮头private Transform firePoint; // 开火点private Transform hp; // 血条private GameObject bulletPrefab; // 炮弹预设体private float rotateSpeed = 0.4f; // 坦克转向速度private float fireWaitTime = float.MaxValue; // 距离上次开火已等待时间private float bulletCoolTime = 1f; // 炮弹冷却时间// Start is called before the first frame updatevoid Start(){target = GameObject.Find("Player/Top").transform;top = transform.Find("Top");firePoint = transform.Find("Top/Gun/FirePoint");hp = transform.Find("HP");bulletPrefab = (GameObject)Resources.Load("Prefabs/Bullet");}// Update is called once per framevoid Update(){fireWaitTime += Time.deltaTime;if (LookAtTarget()) {Fire();}HPLookAtCamera();}private bool LookAtTarget(){Vector3 dir = target.position - top.position;float angle = Vector3.Angle(dir, top.forward);if(angle > 5){int axis = Vector3.Dot(Vector3.Cross(dir, top.forward), Vector3.up) > 0 ? -1 : 1;GetComponent<Rigidbody>().angularVelocity = axis * Vector3.up * rotateSpeed;return false;}GetComponent<Rigidbody>().velocity = Vector3.zero;return true;}private void HPLookAtCamera(){Vector3 cameraPos = Camera.main.transform.position;Vector3 target = new Vector3(cameraPos.x, hp.position.y, cameraPos.z);hp.LookAt(target);}private void Fire(){if(fireWaitTime > bulletCoolTime){BulletInfo bulletInfo = new BulletInfo("EnemyBullet", Color.yellow, top.forward, 5f, 10f);GameObject bullet = Instantiate(bulletPrefab, firePoint.position, Quaternion.identity); // 通过预设体创建炮弹bullet.AddComponent<BulletController>().SetBulletInfo(bulletInfo);fireWaitTime = 0;}}}