unity官方教程-TANKS（二）

上一教程中我们完成了场景设置和坦克设置，今天接着上一教程继续
传送门：unity官方教程-TANKS（一）

在我们设置好了坦克预置后，接下来就是相机设置了

一、相机配置

1、在Hierarchy面板中创建一个空物体，重命名为CameraRig，选中该物体后在Inspector面板重置它的位置属性，点击图中位置，然后将Rotation属性设置为（40，60，0）

2、在Hierarchy面板中将Main Camera拖动到CameraRig上使其成为CameraRig的子物体，设置Main Camera的Position属性为（0，0，-65），Rotation属性为（0,0,0）
3、为了使相机跟随坦克移动，需要编程实现(代码为Scripts/Camera/CameraControll.cs)，因为是两台坦克对战，相机需要照顾到两台坦克，即找到两台坦克的中间位置，将相机移动到那个位置

    private void FindAveragePosition()
    {
        Vector3 averagePos = new Vector3();
        int numTargets = 0;
        //找到两台坦克的位置
        for (int i = 0; i < m_Targets.Length; i++)
        {
            // 坦克
            if (!m_Targets[i].gameObject.activeSelf)
                continue;
            // 两台坦克位置相加
            averagePos += m_Targets[i].position;
            numTargets++;
        }
        //求坦克平均位置
        if (numTargets > 0)
            averagePos /= numTargets;
        // 保持y轴位置不变
        averagePos.y = transform.position.y;
        m_DesiredPosition = averagePos;
    }

4、在两台坦克距离变远或变近时，只移动相机位置是不够的，同时需要将相机拉近或拉远以防止坦克跑出镜头，这一步是通过调整相机的Size属性实现

    private float FindRequiredSize()
    {
        // 世界坐标系转为相机坐标系
        Vector3 desiredLocalPos = transform.InverseTransformPoint(m_DesiredPosition);
        float size = 0f;
        //找到两台坦克中较远的那个，为了使它能进入相机镜头
        for (int i = 0; i < m_Targets.Length; i++)
        {
            if (!m_Targets[i].gameObject.activeSelf)
                continue;
            // 将坦克位置从世界坐标系转为相机坐标系
            Vector3 targetLocalPos = transform.InverseTransformPoint(m_Targets[i].position);
            //计算坦克与相机的位置差
            Vector3 desiredPosToTarget = targetLocalPos - desiredLocalPos;
            // 根据位置差找出合适的Size
            size = Mathf.Max(size, Mathf.Abs(desiredPosToTarget.y));
            size = Mathf.Max(size, Mathf.Abs(desiredPosToTarget.x) / m_Camera.aspect);
        }
        // 添加适当的距离，否则坦克将出现在屏幕边缘
        size += m_ScreenEdgeBuffer;
        size = Mathf.Max(size, m_MinSize);
        return size;
    }

二、坦克生命值

效果如图，绿色代表坦克的生命值，该效果是通过UI实现的，跟着步骤走就可以实现出效果，但对于每一步骤为什么这么做则需要自己实验看看了

1、在Hierarchy中创建一个UI->Slider，选择EventSystem，将Standalone Input Module的Horizontal Axis属性改为HorizontalUI，Vertical Axis属性改为VerticalUI
2、选择Canvas，将Canvas Scaler组件的Reference Pixels per Unit改为1，将Canvas组件的Render Mode改为World Space
3、将Canvas物体拖拽到Tank上，选择Canvas，修改其Position属性为（0,0.1,0），Width属性为3.5，Height属性为3.5，Rotation属性为（90,0,0），保存场景
4、展开Canvas的所有子物体，删掉HandleSlideArea，将其它子物体全部选中，点击图示位置，按住Alt键，同时点击右下角的选项

5、选择Slider物体，取消Interactable，修改Transition为none，调整Max Value和Value为100，重命名Slider为HealthSlider
6、选中Background，将Image组件的Image Source属性修改为Health Wheel，修改Color属性的Alpha值为80
7、选中Fill物体，将Image组件的Image Source属性修改为Health Wheel，修改Color属性的Alpha值为150，Image Type属性为Filled，Fill Origin属性为Left，取消Clockwise
8、在Scripts/UI文件夹找到UIDireactionControl.cs脚本，拖拽到HealthSlider物体上
9、选中Tank物体，点击Inspector面板的Apply，将修改运用到预置

三、爆炸特效

1、找到Prefabs文件夹下的TankExplosion，拖拽到Hierarchy中，给其添加一个AudioSource组件，AudioClip属性选择为TankExplosion，取消Play On Awake
2、选中TankExplosion，点击Inspector面板中的Apply更新预置
3、从Hierarchy中删除TankExplosion

四、坦克生命值脚本控制

1、找到Scripts/Tank/TankHealth.cs脚本，替换为以下内容

using UnityEngine;
using UnityEngine.UI;

public class TankHealth : MonoBehaviour
{
    public float m_StartingHealth = 100f;               // The amount of health each tank starts with.
    public Slider m_Slider;                             // The slider to represent how much health the tank currently has.
    public Image m_FillImage;                           // The image component of the slider.
    public Color m_FullHealthColor = Color.green;       // The color the health bar will be when on full health.
    public Color m_ZeroHealthColor = Color.red;         // The color the health bar will be when on no health.
    public GameObject m_ExplosionPrefab;                // A prefab that will be instantiated in Awake, then used whenever the tank dies.


    private AudioSource m_ExplosionAudio;               // The audio source to play when the tank explodes.
    private ParticleSystem m_ExplosionParticles;        // The particle system the will play when the tank is destroyed.
    private float m_CurrentHealth;                      // How much health the tank currently has.
    private bool m_Dead;                                // Has the tank been reduced beyond zero health yet?


    private void Awake()
    {
        // Instantiate the explosion prefab and get a reference to the particle system on it.
        m_ExplosionParticles = Instantiate(m_ExplosionPrefab).GetComponent();

        // Get a reference to the audio source on the instantiated prefab.
        m_ExplosionAudio = m_ExplosionParticles.GetComponent();

        // Disable the prefab so it can be activated when it's required.
        m_ExplosionParticles.gameObject.SetActive(false);
    }


    private void OnEnable()
    {
        // When the tank is enabled, reset the tank's health and whether or not it's dead.
        m_CurrentHealth = m_StartingHealth;
        m_Dead = false;

        // Update the health slider's value and color.
        SetHealthUI();
    }


    public void TakeDamage(float amount)
    {
        // Reduce current health by the amount of damage done.
        m_CurrentHealth -= amount;

        // Change the UI elements appropriately.
        SetHealthUI();

        // If the current health is at or below zero and it has not yet been registered, call OnDeath.
        if (m_CurrentHealth <= 0f && !m_Dead)
        {
            OnDeath();
        }
    }


    private void SetHealthUI()
    {
        // Set the slider's value appropriately.
        m_Slider.value = m_CurrentHealth;

        // Interpolate the color of the bar between the choosen colours based on the current percentage of the starting health.
        m_FillImage.color = Color.Lerp(m_ZeroHealthColor, m_FullHealthColor, m_CurrentHealth / m_StartingHealth);
    }


    private void OnDeath()
    {
        // Set the flag so that this function is only called once.
        m_Dead = true;

        // Move the instantiated explosion prefab to the tank's position and turn it on.
        m_ExplosionParticles.transform.position = transform.position;
        m_ExplosionParticles.gameObject.SetActive(true);

        // Play the particle system of the tank exploding.
        m_ExplosionParticles.Play();

        // Play the tank explosion sound effect.
        m_ExplosionAudio.Play();

        // Turn the tank off.
        gameObject.SetActive(false);
    }
}

2、将脚本拖拽到Tank物体上，然后拖拽HealthSlider到TankHealth的Slider属性，Fill物体到FillImage属性，TankExplosion到ExplosionPrefab属性
3、选中Tank物体，点击Inspector面板的Apply，将修改应用到预置，保存场景

以上就是今天的主要内容了，下期教程继续。。。