Unity3D攻击效果及自动寻路简单实现

Hit And Run Practice

Introduction

在RPG游戏中，控制角色对敌方单位进行攻击这样的战斗系统几乎是必备的，而在战斗系统中，根据玩家的输入进行角色的自动寻路则也是系统的基础功能。这个DEMO主要介绍了一个简单战斗表现的实现和利用NavMesh进行自动寻路。

Battle System

战斗系统的实现思路步骤如下：
* 在Unity3D中导入一个人物模型，并创建一个可供人物活动的Terrain
* 调整摄像机至正确的视角（可以始终处于人物背后也可以45度俯角跟随）
* 创建攻击动画与伤害显示
* 创建血条
* 逻辑脚本编写（包括攻击方向与距离求解，攻击物体判定）
* 运行测试

其中，对于具体的攻击在每一帧中的实现逻辑思路如下（攻击动作由鼠标与攻击按键共同完成，鼠标位置代表攻击方向，按键则给出攻击指令）：
* 获取鼠标位置Input.MousePosition
* 由当前鼠标位置与角色位置求出攻击方向向量并归一化
* 由角色位置向攻击方向向量做出一条长度为攻击距离的线段，求解与线段相交的物体集合
* 遍历物体集合，对其中的可攻击对象执行HIT方法
* 播放角色攻击动画,如攻击方向与角色朝向不一致则先进行角色转身

角色控制脚本主要Code如下:

using UnityEngine;
using UnityEngine.AI;
using System;
using System.Collections;
using System.Collections.Generic;
#pragma warning disable

public class ASCLBasicController : MonoBehaviour 
{
    Animator animator;
    public Collider     floorPlane;//in this demonstration this is set manually, the Retail Ability system has methods for dealing with this automatically via data structures for environments
    public Collider     attackPlane;
    public Enemy[]      enemies;//this array is filled during START by searching for prefabs that have the enemy script attached to them
    public Transform    hitReport;//this is for a text mesh object that tells us what damage we did...we need to know where this instance is so we can instantiate off of it
    public Transform    particleHit;//this is for a particle emmiter that shows us a hit...we need to know where this instance is so we can instantiate off of it
                                        //the retail ability system will have this "Inside" an abilities class structual data

    public List<Ability>    abilities = new List<Ability>();//not really actual abilities as yet, HERE they are only attacks...the retail Ability System package will have actual ones 
    int                     ahc=1; //ability hit counter, combo attacks have more than one hit, this variable keeps track of how many hits we have used in update

    public bool         hitCheck;//<<< IMPORTANT mecanim tells us to perform a hit check at a specific point in attack animations by settting this to TRUE

    public int          WeaponState=0;//unarmed, 1H, 2H, bow, dual, pistol, rifle, spear and ss(sword and shield)
    public bool         wasAttacking;// we need this so we can take lock the direction we are facing during attacks, mecanim sometimes moves past the target which would flip the character around wildly

    public Renderer     movementTarget;
    Transform           destFloor;

    float               rotateSpeed = 20.0f; //used to smooth out turning

    public Vector3      attackPos;
    public Vector3      lookAtPos;
    float               gravity = -0.3f;//unused in this demonstration
    float               fallspeed = 0.0f;


    NavMeshAgent mr;
    bool isArrived;




    public bool rightButtonDown=false;//we use this to "skip out" of consecutive right mouse down input...

    // Use this for initialization
    void Start () 
    {   
        animator = GetComponentInChildren<Animator>();//need this...
        movementTarget.transform.position = transform.position;//initializing our movement target as our current position
        movementTarget.enabled = true;
        lookAtPos = transform.position+transform.forward;
        enemies = Transform.FindObjectsOfType(typeof(Enemy))as Enemy[];//find all the instances of the enemy script which are attached to the targets


        mr = GetComponent<NavMeshAgent>();
        isArrived = true;

    }

    // Update is called once per frame
    void LateUpdate () 
    {
        if(hitCheck)//hitCheck is a boolean variable, it gets set by mecanim attack states, if mecanim set it...then we need to do hit checks right now
        {

            if(ahc<1) ahc=1;//we may have a "double pulse" coming from Mecanim so...
            AbilityCollision abilColl = new AbilityCollision();
            abilColl = abilities[WeaponState].collChecks[abilities[WeaponState].collChecks.Count-ahc];
            if(abilColl.type==0)
            {
                //ANGLE RANGE which can be used for any angle/range including radial attacks
                for(int i =0;i<enemies.Length;i++)//loop throught the enemies
                {
                    CheckForHit(enemies[i], abilColl);//ahc= ability hit counter, which is used for indexing a a one tow three punch combo for example...
                }
                ahc-=1;// some abilities have multiple checks, so when we use an ability, we set ahc to the number of hits in the ability (combo punches for example)
            }
            else if(abilColl.type==1)
            {
                //Missiles
                //are a special type, my enemies are its enemies, my damage is its damage, it needs to know who I am, and which of my abilities used it this time
                Transform tm = (Transform) Instantiate(abilColl.missile , abilColl.missile.position,abilColl.missile.rotation);
                tm.gameObject.SetActive(true);
                Missile missile = tm.GetComponent<Missile>();
                missile.speed = abilColl.speed;
                missile.damage = abilColl.damage;
                missile.enemies = enemies;
                missile.abc = this;
            }
            if(abilColl.type==2)
            {
                //Beams/Bullets
                Transform tm = (Transform) Instantiate(abilColl.missile , abilColl.missile.position,abilColl.missile.rotation);
                tm.gameObject.SetActive(true);
                RayShot rayshot = tm.GetComponent<RayShot>();
                rayshot.damage = abilColl.damage;
                rayshot.enemies = enemies;
                Vector3 tempPos = attackPos;
                tempPos.y = abilColl.missile.position.y;
                Vector3 tempdelta = Vector3.Normalize(tempPos - abilColl.missile.position); //this is the actual vector from the source point to the attack point normalized
                rayshot.endPos = tempdelta* abilColl.range;
                rayshot.abc = this;
            }

            hitCheck = false;// we are done checking, reset the hitCheck bool
        }

        RaycastHit hit;// RayCastHits hold very useful info such as hitnormal and location
        Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition);//get a ray that goes from the camera -> "THROUGH" the mouse pointer - > and out into the scene

        if ( ! Input.GetKey(KeyCode.LeftAlt))//if we are not using the ALT key(camera control)...
        {
            // floor goal   
            if(Input.GetMouseButton(0))//is the left mouse button being clicked?
            {
                if(floorPlane.Raycast(ray, out hit, 500.0f)) //check to see if that ray hits our "floor"                                                
                {







                    movementTarget.transform.position = hit.point;//mark it where it hit
                    movementTarget.enabled=true;

                    mr.SetDestination(hit.point);
                    lookAtPos = hit.point;
                    lookAtPos.y = transform.position.y;
                    wasAttacking = false;//we're moving now, not attacking




                }
            }
        }

        switch(Input.inputString)//get keyboard input, probably not a good idea to use strings here...Garbage collection problems with regards to local string usage are known to happen
        {                        //the garbage collection memory problem arises from local alloction of memory, and not freeing it up efficiently
            case "p":
                animator.SetTrigger("Pain");//the animator controller will detect the trigger pain and play the pain animation
                break;
            case "a":
                animator.SetInteger("Death", 1);//the animator controller will detect death=1 and play DeathA
                break;
            case "b":
                animator.SetInteger("Death", 2);//the animator controller will detect death=2 and play DeathB
                break;
            case "c":
                animator.SetInteger("Death", 3);//the animator controller will detect death=3 and play DeathC
                break;
            case "n":
                animator.SetBool("NonCombat", true);//the animator controller will detect this non combat bool, and go into a non combat state "in" this weaponstate
                break;
            default:
                break;
        }

        animator.SetInteger("WeaponState", WeaponState);// probably would be better to check for change rather than bashing the value in like this

        if ( ! Input.GetKey(KeyCode.LeftAlt)) // if we're changing camera transforms, do not use "USE"
        {
            if(Input.GetMouseButton(1) || Input.GetKey(KeyCode.K))// are we using the right button?
            {
                //Debug.Log ("11111111111111");
                if(rightButtonDown != true)// was it previously down? if so we are already using "USE" bailout (we don't want to repeat attacks 800 times a second...just once per press please
                {
                    attackPlane.enabled=true;
                    if(attackPlane.Raycast(ray, out hit, 500.0f))                                               
                    {
                        movementTarget.transform.position = transform.position; //we are attacking so lock our position to where we are
                        attackPos = hit.point;// establish the point that we hit with the mouse
                        attackPos.y = transform.position.y;//use our height for the LOOKAT function, so we stay level and dont lean the character in weird angles
                        Vector3 attackDelta = attackPos - transform.position;//we need the Vector delta which is an un-normalized direction vector
                        lookAtPos = attackPos;
                        animator.SetTrigger("Use");//tell mecanim to do the attack animation(trigger)

                        ahc = abilities[WeaponState].collChecks.Count;//ahc=ability hit counter, used for animations that have multiple hits like combos
                        animator.SetBool("Idling", true);//stop moving
                        rightButtonDown = true;//right button was not down before, mark it as down so we don't attack 800 frames a second 
                        wasAttacking =true;//some mecanims will actually move us past the target, so we want to keep looking in one direction instead of spinning wildly around the target
                    }
                    attackPlane.enabled=false;
                }
            }
        }

        if (Input.GetMouseButtonUp(1) || Input.GetKeyUp(KeyCode.K))//ok, we can clear the right mouse button and use it for the next attack
        {
            if (rightButtonDown == true)
            {
                rightButtonDown = false;
            }
        }


        Debug.DrawLine ((movementTarget.transform.position + transform.up*2), movementTarget.transform.position);//useful for visuals in editor

        //We need to handle elevation for mecanim here...we will be doing our ground check right now
        //GROUND check

        ray.direction = transform.up*-1;
        ray.origin = transform.position+transform.up;

        //need two casts...one for velocity ahead of us
        //and one for where we are
        //we need the time from the last frame, as well as the distance traveled since that frame

        //RAMPS,Coming down from Jumps and Falling
        if(floorPlane.Raycast(ray, out hit, 1.0f))
        {
            //always hit if we are going up
            if(hit.point.y>(transform.position.y + 0.02f))
            {
                transform.position=hit.point;
                lookAtPos.y = transform.position.y;
                fallspeed=0.0f;
            }
        }
        else if(floorPlane.Raycast(ray, out hit, 1.2f))
        {
            //lower hit check for going down ramps specifically
            if(hit.point.y < (transform.position.y - 0.02f))
            {
                transform.position=hit.point;
                lookAtPos.y = transform.position.y;
                fallspeed=0.0f;
            }
        }
        else
        {//Falling
            transform.parent=null;
            lookAtPos=transform.position;
            movementTarget.transform.position=transform.position;
            movementTarget.transform.parent=null;

            fallspeed+=0.3f;
            Vector3 v = new Vector3(0.0f,fallspeed*Time.deltaTime,0.0f);
            transform.position-=v;
        }

        Debug.DrawLine ((movementTarget.transform.position + transform.up*2), lookAtPos+ transform.up*2);//useful for visuals in editor

        if(transform.parent == floorPlane.transform)
        {
            lookAtPos = movementTarget.transform.position;
        }
        lookAtPos.y = transform.position.y;
        Quaternion tempRot = transform.rotation;    //save current rotation
        transform.LookAt(lookAtPos);                        
        Quaternion hitRot = transform.rotation;     // store the new rotation
        // now we slerp orientation
        transform.rotation = Quaternion.Slerp(tempRot, hitRot, Time.deltaTime * rotateSpeed);


        if(Vector3.Distance(movementTarget.transform.position,transform.position)>0.5f)
        {
            animator.SetBool("Idling", false);
        }
        else
        {
            animator.SetBool("Idling", true);
            movementTarget.enabled = false;
        }

    }

    void OnGUI()
    {
        string tempString = "LMB=move RMB=attack p=pain abc=deaths";
        GUI.Label (new Rect (10, 5,1000, 20), tempString);
    }

    void CheckForHit(Enemy en, AbilityCollision ac)
    {
        //AngleRanged
        if(ac.type==0)
        {
            float angle=ac.angle/2;
            Vector3 tDelta = en.gameObject.transform.position - transform.position;
            float tAngle = Vector3.Angle(transform.forward,tDelta);
            if (tAngle< 0) tAngle*=-1;
            if (tAngle<angle)
            {
                if(Vector3.Distance(transform.position, en.gameObject.transform.position)<ac.range)
                {
                    //we have a hit
                    //AngleRanged
                    Transform tm = (Transform) Instantiate(hitReport , (en.gameObject.transform.position + new Vector3(0.0f,1.6f,0.0f)),Quaternion.identity);
                    tm.gameObject.SetActive(true);
                    Hit tmHit = tm.GetComponent<Hit>();
                    tmHit.text = ac.damage.ToString();
                    Transform ph = (Transform) Instantiate(particleHit , (en.gameObject.transform.position + new Vector3(0.0f,1.5f,0.0f)),Quaternion.identity);
                    ph.transform.LookAt(Camera.main.transform.position);
                    ph.transform.position += (ph.transform.forward * 2.0f);
                    ph.gameObject.SetActive(true);
                }
            }
        }
        return;
    }
}

Hit脚本主要Code如下：

using UnityEngine;
using System.Collections;

public class Hit : MonoBehaviour 
{
    public TextMesh yellow;
    public TextMesh black;
    float           startTime;
    float           currentTime;
    public float    lifespan; //in seconds

    public float    fadeTime;   //in seconds
    public float    fadeSpeed;  //in seconds

    public float    maxSize;
    public float    speed; // meters per second

    public string   text;
    // Use this for initialization
    void Start () 
    {
        startTime = Time.fixedTime;
    }

    // Update is called once per frame
    void Update () 
    {
        //destroy this hit report if we are past it's lifespan
        currentTime = Time.fixedTime - startTime;
        if(currentTime > lifespan)
        {
            Destroy(gameObject);
        }

        //fade out
        if(currentTime > fadeTime)
        {
            float fade = (fadeTime -(currentTime-fadeTime)) * (1/fadeSpeed);
            Color tempColor = yellow.color;
            tempColor.a = fade;
            yellow.color = tempColor;

            tempColor = black.color;
            tempColor.a = fade;
            black.color = tempColor;
        }

        //scale and lift accordingly
        if(transform.localScale.x < maxSize)
        {
            transform.localScale = new Vector3 (1.0f,1.0f,1.0f) * (0.01f + currentTime) * 3.0f;
        }
        transform.position += (Vector3.up * Time.deltaTime * speed);
        transform.LookAt(Camera.main.transform.position);

        yellow.text = text;
        black.text = text;
    }
}

NavMesh

自动寻路则主要是用的Unity3D的NavMesh系统实现：
* 搭建好具体场景
* 选择地面与可以产生碰撞的物体
* 将上述物体设为Navigation Static
* 点击Bake进行路线烘焙
* 编写脚本实现鼠标点击自动寻路
* 将脚本绑定到要自动寻路的角色
脚本Code如下：

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

public class navmesh : MonoBehaviour {


    private NavMeshAgent mr;
    // Use this for initialization
    void Start () {
        mr = GetComponent<NavMeshAgent> ();
    }

    // Update is called once per frame
    void Update () {
        if (Input.GetMouseButtonDown(0))
        {

            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit rayhit; 
            if (Physics.Raycast(ray, out rayhit))  
            {
                if (rayhit.transform.name == "Terrain") 
                {
                    mr.SetDestination(rayhit.point);
                }
            }
        }


    }
}