4-4 On Alarm 场景阴影和警报灯闪烁的制作

夜行的猫仔

如何在游戏中创建警报灯，并通过脚本控制灯光的衰减。
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书本原文节选：
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C#代码

1. using UnityEngine;
   
2. using System.Collections;
   
3. 
   
4. public class AlarmLight : MonoBehaviour
   
5. {
   
6.     public float fadeSpeed = 2f;          // 光渐渐淡化的速度.
   
7.     public float highIntensity = 2f;       // 报警灯最高的亮度.
   
8.     public float lowIntensity = 0.5f;      // 报警灯最低的亮度.
   
9.     public float changeMargin = 0.2f;    // 目标强度变化的范围.
   
10.     public bool alarmOn;                // 报警灯是否被激活.
    
11. 
    
12.     private float targetIntensity;          // 当前光强度
    
13.    
    
14.    
    
15.     void Awake ()
    
16.     {
    
17.         // 当游戏刚刚启动的时候，报警灯的强度为0，将不会对场景产生影响
    
18.         light.intensity = 0f;
    
19.         
    
20.         // 当第一次警报灯被激活的时候, 警报色应该是最亮的
    
21.         targetIntensity = highIntensity;
    
22.     }
    
23.    
    
24.    
    
25.     void Update ()
    
26.     {
    
27.         // 当警报灯激活响起
    
28.         if(alarmOn)
    
29.         {
    
30.             // ... 循环操作光的从当前强度变为targetIntensity强度
    
31.             light.intensity = Mathf.Lerp(light.intensity, targetIntensity, fadeSpeed * Time.deltaTime);
    
32.             
    
33.             // 切换光强变弱还是从弱变强
    
34.             CheckTargetIntensity();
    
35.         }
    
36.         else
    
37.             // 如果警报没有激活则将警报色强度渐变为0.
    
38.             light.intensity = Mathf.Lerp(light.intensity, 0f, fadeSpeed * Time.deltaTime);
    
39.     }
    
40.    
    
41.    
    
42.     void CheckTargetIntensity ()
    
43.     {
    
44.         // 如果灯光当前的亮度接近亮度范围的一端了，则需要将当targetIntensity颜色变成另外一个端的颜色....
    
45.         if(Mathf.Abs(targetIntensity - light.intensity) < changeMargin)
    
46.         {
    
47.             // ... 如果当前的灯光已经最亮了...
    
48.             if(targetIntensity == highIntensity)
    
49.                 // ... 则将targetIntensity的值变成最低.
    
50.                 targetIntensity = lowIntensity;
    
51.             else
    
52.                 //否则将targetIntensity的值变成最高.
    
53.                 targetIntensity = highIntensity;
    
54.         }
    
55.     }
    
56. }
    

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JS代码

1. #pragma strict
   
2. 
   
3. public var fadeSpeed : float = 2f;          // How fast the light fades between intensities.
   
4. public var highIntensity : float = 2f;      // The maximum intensity of the light whilst the alarm is on.
   
5. public var lowIntensity : float = 0.5f;     // The minimum intensity of the light whilst the alarm is on.
   
6. public var changeMargin : float = 0.2f;     // The margin within which the target intensity is changed.
   
7. public var alarmOn : boolean;               // Whether or not the alarm is on.
   
8. 
   
9. 
   
10. private var targetIntensity : float;        // The intensity that the light is aiming for currently.
    
11. 
    
12. 
    
13. function Awake ()
    
14. {
    
15.     // When the level starts we want the light to be "off".
    
16.     light.intensity = 0f;
    
17.    
    
18.     // When the alarm starts for the first time, the light should aim to have the maximum intensity.
    
19.     targetIntensity = highIntensity;
    
20. }
    
21. 
    
22. 
    
23. function Update ()
    
24. {
    
25.     // If the light is on...
    
26.     if(alarmOn)
    
27.     {
    
28.         // ... Lerp the light's intensity towards the current target.
    
29.         light.intensity = Mathf.Lerp(light.intensity, targetIntensity, fadeSpeed * Time.deltaTime);
    
30.         
    
31.         // Check whether the target intensity needs changing and change it if so.
    
32.         CheckTargetIntensity();
    
33.     }
    
34.     else
    
35.         // Otherwise fade the light's intensity to zero.
    
36.         light.intensity = Mathf.Lerp(light.intensity, 0f, fadeSpeed * Time.deltaTime);
    
37. }
    
38. 
    
39. 
    
40. function CheckTargetIntensity ()
    
41. {
    
42.     // If the difference between the target and current intensities is less than the change margin...
    
43.     if(Mathf.Abs(targetIntensity - light.intensity) < changeMargin)
    
44.     {
    
45.         // ... if the target intensity is high...
    
46.         if(targetIntensity == highIntensity)
    
47.             // ... then set the target to low.
    
48.             targetIntensity = lowIntensity;
    
49.         else
    
50.             // Otherwise set the targer to high.
    
51.             targetIntensity = highIntensity;
    
52.     }
    
53. }

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涉及到的知识点：
灯光 Light