unity暂停

提条件:在项目中用过Time.timeScale = 0来实现游戏暂停

问题: 暂停游戏后，暂停界面的按钮可能需要播放一个idle时的动画，Time.timeScale=0 会影响动画播放。

受Time.timeScale影响的因素:

1.物理模拟. FixedUpdate - 当Time.timeScale=0时，FixedUpdate 函数不会被执行，但是Update函数是会执行的。

2.Coroutines. - Time.timeScale=0 协程函数不会停止,但是会停止WaitForSeconds. 协成函数还是会每一帧都触发，但是WaitForSeconds使用的是当前的Time.deltaTime会变成0

3.Invoke 和 InvokeRepeating. -延迟一段时间后掉用指定函数.

4.Particle System 粒子系统.

5.Animations. -动画. 如果我们使用的是Animator，可以设置动画忽略Time.timeScale带来的影响. 只需要把UpdateMode设置为UnScaled Time。

timeScale表示游戏中时间流逝快慢的尺度。这个参数是用来做慢动作效果的。

对于将timeScale设置为0的情况，仅只有一个补充说明。

在实际使用中，通过设置timeScale来实现慢动作特效，是一种相当简洁且不带任何副作用的方法.

但是当将timeScale设置为0来实现暂停时，由于时间不再流逝，所有和时间有关的功能都将停止，有些时候这正是我们想要的，因为毕竟是暂停。

但是副作用也随之而来，在暂停时各种动画和粒子效果都将无法播放（因为是时间相关的），FixedUpdate也将不再被调用。

那么我又如何通过timeScale来实现上面的效果呢？

刚好realtimeSinceStartup 与 timeScale 就无关，也就是说realtimeSinceStartup 不受timeScale 的影响。

因此realtimeSinceStartup 也就成了解决在暂停下的动画和粒子效果的救命稻草。对于Unity动画，

在每一帧，根据实际时间寻找相应帧并采样显示的方法来模拟动画，

<code class="hljs cs has-numbering"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> IEnumerator <span class="hljs-title">Play</span>( <span class="hljs-keyword">this</span> Animation animation, <span class="hljs-keyword">string</span> clipName, <span class="hljs-keyword">bool</span> ignoreTimeScale, Action onComplete )
{
<span class="hljs-comment">//We don't want to use timeScale, so we have to animate by frame..</span>
<span class="hljs-keyword">if</span>(ignoreTimeScale)
{
AnimationState _currState = animation[clipName];
<span class="hljs-keyword">bool</span> isPlaying = <span class="hljs-keyword">true</span>;

<span class="hljs-keyword">float</span> _progressTime = <span class="hljs-number">0</span>F;
<span class="hljs-keyword">float</span> _timeAtLastFrame = <span class="hljs-number">0</span>F;
<span class="hljs-keyword">float</span> _timeAtCurrentFrame = <span class="hljs-number">0</span>F;
<span class="hljs-keyword">bool</span> _inReversePlaying = <span class="hljs-keyword">false</span>;

<span class="hljs-keyword">float</span> _deltaTime = <span class="hljs-number">0</span>F;
animation.Play(clipName);
_timeAtLastFrame = Time.realtimeSinceStartup;

<span class="hljs-keyword">while</span> (isPlaying) {
_timeAtCurrentFrame = Time.realtimeSinceStartup;
_deltaTime = _timeAtCurrentFrame - _timeAtLastFrame;
_timeAtLastFrame = _timeAtCurrentFrame;

_progressTime += _deltaTime;

_currState.normalizedTime = _inReversePlaying ? <span class="hljs-number">1.0</span>f - (_progressTime / _currState.length)
: _progressTime / _currState.length;
animation.Sample();

<span class="hljs-keyword">if</span> (_progressTime >= _currState.length) {
<span class="hljs-keyword">switch</span> (_currState.wrapMode) {
<span class="hljs-keyword">case</span> WrapMode.Loop:
<span class="hljs-comment">//Loop anim, continue.</span>
_progressTime = <span class="hljs-number">0.0</span>f;
<span class="hljs-keyword">break</span>;
<span class="hljs-keyword">case</span> WrapMode.PingPong:
<span class="hljs-comment">//PingPong anim, reversing continue.</span>
_progressTime = <span class="hljs-number">0.0</span>f;
_inReversePlaying = !_inReversePlaying;
<span class="hljs-keyword">break</span>;
<span class="hljs-keyword">case</span> WrapMode.ClampForever:
<span class="hljs-comment">//ClampForever anim, keep the last frame.</span>
<span class="hljs-keyword">break</span>;
<span class="hljs-keyword">case</span> WrapMode.Default:
<span class="hljs-comment">//We don't know how to handle it.</span>
<span class="hljs-comment">//In most time, this means it's a Once anim.</span>
<span class="hljs-comment">//Animation should be played with wrap mode specified.</span>
Debug.LogWarning(<span class="hljs-string">"A Default Anim Finished. Animation should be played with wrap mode specified."</span>);
isPlaying = <span class="hljs-keyword">false</span>;
<span class="hljs-keyword">break</span>;
<span class="hljs-keyword">default</span>:
<span class="hljs-comment">//Once anim, kill it.</span>
isPlaying = <span class="hljs-keyword">false</span>;
<span class="hljs-keyword">break</span>;
}
}
<span class="hljs-keyword">yield</span> <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> WaitForEndOfFrame();
}
<span class="hljs-keyword">yield</span> <span class="hljs-keyword">return</span> <span class="hljs-keyword">null</span>;

<span class="hljs-keyword">if</span>(onComplete != <span class="hljs-keyword">null</span>) {
onComplete();
}
} <span class="hljs-keyword">else</span> {
<span class="hljs-keyword">if</span> (onComplete != <span class="hljs-keyword">null</span>) {
Debug.LogWarning(<span class="hljs-string">"onComplete will not be called when you set \"ignoreTimeScale\" to true. Use Unity's animation handler instead!)"</span>);
animation.Play(clipName);
}
}
}</code><ul class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li><li>35</li><li>36</li><li>37</li><li>38</li><li>39</li><li>40</li><li>41</li><li>42</li><li>43</li><li>44</li><li>45</li><li>46</li><li>47</li><li>48</li><li>49</li><li>50</li><li>51</li><li>52</li><li>53</li><li>54</li><li>55</li><li>56</li><li>57</li><li>58</li><li>59</li><li>60</li><li>61</li><li>62</li><li>63</li><li>64</li><li>65</li><li>66</li><li>67</li><li>68</li><li>69</li></ul><ul class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li><li>35</li><li>36</li><li>37</li><li>38</li><li>39</li><li>40</li><li>41</li><li>42</li><li>43</li><li>44</li><li>45</li><li>46</li><li>47</li><li>48</li><li>49</li><li>50</li><li>51</li><li>52</li><li>53</li><li>54</li><li>55</li><li>56</li><li>57</li><li>58</li><li>59</li><li>60</li><li>61</li><li>62</li><li>63</li><li>64</li><li>65</li><li>66</li><li>67</li><li>68</li><li>69</li></ul>

注：上面这段代码只对Animation有效，那针对Animator我们又如何在timeScale =0的情况下正常播放动画呢？

如果你是想游戏部分暂停，可以把暂停的部分写到FixedUpdate函数里面，不暂停写到Update函数。

<code class="hljs cs has-numbering"><span class="hljs-keyword">float</span> pauseTime =<span class="hljs-number">2</span>f；
<span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Pause</span>()
{
<span class="hljs-keyword">if</span> (isProp) {
pauseTime -= Time.fixedDeltaTime;
<span class="hljs-keyword">if</span> (pauseTime <= <span class="hljs-number">0</span>) {
isProp = <span class="hljs-keyword">false</span>;
pauseTime = <span class="hljs-number">1</span>f;
Time.timeScale = <span class="hljs-number">1</span>;
}
}
｝
这个是局部暂停的代码。</code>