Unity3d的C#扩展方法Extension methods应用吧

扩展方法的条件：

1. 必须声明为静态类

2. 必须声明为静态方法

3. 方法的第一个参数为this

首先来扩展Unity中的协程Coroutine，

using UnityEngine;
using System.Collections;
using System;

/// <summary>
/// a set of extension methods meant help with common coroutine cases. Example :
/// <code>
/// void OnTriggerEnter(Collider col) {
///     if(col.gameObject.tag != "Ice")
///             return; 
///     Freeze();
///     this.ExecuteLater(()=> Unfreeze(), 2f); // unfreezes the current gameObject 2 seconds from now.
/// }
/// 
/// </code>
/// </summary>

public static class TimingExtension
{
    public delegate bool When();
        /// <summary>
        /// Execute the given Action when <code>condition</code> returns <code>true</code>. 
        /// condition will be evaluated every frame.
        /// </summary>
        /// <param name="action">the action to execute</param>
        /// <param name="condition">Condition.</param>
    public static void ExecuteWhen(this MonoBehaviour m, Action action, When condition)
    {
        m.StartCoroutine(ExecuteWhenCoroutine(action, condition));
    }

        /// <summary>
        /// Execute the action after a delay of <code>seconds</code>
        /// </summary>
        /// <param name="action">Action.</param>
        /// <param name="seconds">Seconds.</param>
    public static void ExecuteLater(this MonoBehaviour m, Action action, float seconds)
    {
        m.StartCoroutine(ExecuteLaterCoroutine(action, seconds));
    }

        /// <summary>
        /// Execute an action next frame
        /// </summary>
        /// <param name="m">M.</param>
        /// <param name="action">Action.</param>
        public static void ExecuteNextFrame(this MonoBehaviour m, Action action)
        {
                m.StartCoroutine(ExecuteNextFrameCoroutine(action));
        }
    private static IEnumerator ExecuteWhenCoroutine(Action action, When condition)
    {
        while (!condition())
            yield return null;
        action();
    }
    private static IEnumerator ExecuteLaterCoroutine(Action action, float seconds)
    {
        yield return new WaitForSeconds(seconds);
        action();
    }
        private static IEnumerator ExecuteNextFrameCoroutine(Action action)
        {
                yield return null;
                action();
        }
    public static void Co(this MonoBehaviour m, Func<IEnumerator> coroutine) 
    {
        m.StartCoroutine(CoCoroutine(coroutine));
    }
    private static IEnumerator CoCoroutine(Func<IEnumerator> coroutine) 
    {
        yield return coroutine;
    }
}

     再来扩展Transform组件的内容，特别是我们相对x,y, z 单独赋值时，有了它是不是方便多了！  就是解决类似于 这样的问题！

transform.position = new Vector3(5f,transform.position.y, transform.position.z); 

看看怎么扩展呢？

using UnityEngine;
using System.Collections;

public static class ExtensionsTransform
{
	// 扩展了只修改一个值的
    public static void SetPositionX(this Transform t, float newX)
    {
        t.position = new Vector3(newX, t.position.y, t.position.z);
    }

    public static void SetPositionY(this Transform t, float newY)
    {
        t.position = new Vector3(t.position.x, newY, t.position.z);
    }

    public static void SetPositionZ(this Transform t, float newZ)
    {
        t.position = new Vector3(t.position.x, t.position.y, newZ);
    }
	// 扩展了更快的获取一个值
    public static float GetPositionX(this Transform t)
    {
        return t.position.x;
    }

    public static float GetPositionY(this Transform t)
    {
        return t.position.y;
    }

    public static float GetPositionZ(this Transform t)
    {
        return t.position.z;
    }
}

看看使用。

using UnityEngine;
using System.Collections;

public class Player : MonoBehaviour 
{
    void Update () 
    {
        //Set new x position to 5
        transform.SetPositionX(5f);//效果是一样的
    }
}

还可以这样扩展Transform！

static public class ExtensionsTransform {
	/// <summary>
	/// Gets or add a component. Usage example: 
	/// BoxCollider boxCollider = transform.GetOrAddComponent<BoxCollider>();
	/// </summary>
	static public T GetOrAddComponent<T> (this Component child) where T: Component {
		T result = child.GetComponent<T>();
		if (result == null) {
			result = child.gameObject.AddComponent<T>();
		}
		return result;
	}
}

接下来看看wiki 上的扩展四元数Quaternion

http://wiki.unity3d.com/index.php/QuaternionExtensions