unity官方教程-TANKS（二）

上一教程中咱們完成了場景設置和坦克設置，今天接着上一教程繼續
傳送門：unity官方教程-TANKS（一）

在咱們設置好了坦克預置後，接下來就是相機設置了

1、相機配置

一、在Hierarchy面板中建立一個空物體，重命名爲CameraRig，選中該物體後在Inspector面板重置它的位置屬性，點擊圖中位置，而後將Rotation屬性設置爲（40，60，0）

二、在Hierarchy面板中將Main Camera拖動到CameraRig上使其成爲CameraRig的子物體，設置Main Camera的Position屬性爲（0，0，-65），Rotation屬性爲（0,0,0）
三、爲了使相機跟隨坦克移動，須要編程實現(代碼爲Scripts/Camera/CameraControll.cs)，由於是兩臺坦克對戰，相機須要照顧到兩臺坦克，即找到兩臺坦克的中間位置，將相機移動到那個位置

private void FindAveragePosition()
    {
        Vector3 averagePos = new Vector3();
        int numTargets = 0;
        //找到兩臺坦克的位置
        for (int i = 0; i < m_Targets.Length; i++)
        {
            // 坦克
            if (!m_Targets[i].gameObject.activeSelf)
                continue;
            // 兩臺坦克位置相加
            averagePos += m_Targets[i].position;
            numTargets++;
        }
        //求坦克平均位置
        if (numTargets > 0)
            averagePos /= numTargets;
        // 保持y軸位置不變
        averagePos.y = transform.position.y;
        m_DesiredPosition = averagePos;
    }

四、在兩臺坦克距離變遠或變近時，只移動相機位置是不夠的，同時須要將相機拉近或拉遠以防止坦克跑出鏡頭，這一步是經過調整相機的Size屬性實現

private float FindRequiredSize()
    {
        // 世界座標系轉爲相機座標系
        Vector3 desiredLocalPos = transform.InverseTransformPoint(m_DesiredPosition);
        float size = 0f;
        //找到兩臺坦克中較遠的那個，爲了使它能進入相機鏡頭
        for (int i = 0; i < m_Targets.Length; i++)
        {
            if (!m_Targets[i].gameObject.activeSelf)
                continue;
            // 將坦克位置從世界座標系轉爲相機座標系
            Vector3 targetLocalPos = transform.InverseTransformPoint(m_Targets[i].position);
            //計算坦克與相機的位置差
            Vector3 desiredPosToTarget = targetLocalPos - desiredLocalPos;
            // 根據位置差找出合適的Size
            size = Mathf.Max(size, Mathf.Abs(desiredPosToTarget.y));
            size = Mathf.Max(size, Mathf.Abs(desiredPosToTarget.x) / m_Camera.aspect);
        }
        // 添加適當的距離，不然坦克將出如今屏幕邊緣
        size += m_ScreenEdgeBuffer;
        size = Mathf.Max(size, m_MinSize);
        return size;
    }

2、坦克生命值

效果如圖，綠色表明坦克的生命值，該效果是經過UI實現的，跟着步驟走就能夠實現出效果，但對於每一步驟爲何這麼作則須要本身實驗看看了

一、在Hierarchy中建立一個UI->Slider，選擇EventSystem，將Standalone Input Module的Horizontal Axis屬性改成HorizontalUI，Vertical Axis屬性改成VerticalUI
二、選擇Canvas，將Canvas Scaler組件的Reference Pixels per Unit改成1，將Canvas組件的Render Mode改成World Space
三、將Canvas物體拖拽到Tank上，選擇Canvas，修改其Position屬性爲（0,0.1,0），Width屬性爲3.5，Height屬性爲3.5，Rotation屬性爲（90,0,0），保存場景
四、展開Canvas的全部子物體，刪掉HandleSlideArea，將其它子物體所有選中，點擊圖示位置，按住Alt鍵，同時點擊右下角的選項

五、選擇Slider物體，取消Interactable，修改Transition爲none，調整Max Value和Value爲100，重命名Slider爲HealthSlider
六、選中Background，將Image組件的Image Source屬性修改成Health Wheel，修改Color屬性的Alpha值爲80
七、選中Fill物體，將Image組件的Image Source屬性修改成Health Wheel，修改Color屬性的Alpha值爲150，Image Type屬性爲Filled，Fill Origin屬性爲Left，取消Clockwise
八、在Scripts/UI文件夾找到UIDireactionControl.cs腳本，拖拽到HealthSlider物體上
九、選中Tank物體，點擊Inspector面板的Apply，將修改運用到預置

3、爆炸特效

一、找到Prefabs文件夾下的TankExplosion，拖拽到Hierarchy中，給其添加一個AudioSource組件，AudioClip屬性選擇爲TankExplosion，取消Play On Awake
二、選中TankExplosion，點擊Inspector面板中的Apply更新預置
三、從Hierarchy中刪除TankExplosion

4、坦克生命值腳本控制

一、找到Scripts/Tank/TankHealth.cs腳本，替換爲如下內容

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<ParticleSystem>();

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

        // 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);
    }
}

二、將腳本拖拽到Tank物體上，而後拖拽HealthSlider到TankHealth的Slider屬性，Fill物體到FillImage屬性，TankExplosion到ExplosionPrefab屬性
三、選中Tank物體，點擊Inspector面板的Apply，將修改應用到預置，保存場景

以上就是今天的主要內容了，下期教程繼續。。。