January 2020
Intermediate to advanced
356 pages
6h 4m
Chinese
Content preview from Swift游戏开发经典实例
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208
｜
第
6
章
animatedSprite.run(SKAction.repeatForever(animationAction))
讨论
SKAction
类能够实时改变精灵的纹理贴图。如果我们想基于连续位图来生成动画，
我们所需要做的仅仅是将所有位图转换为
SKTexture
对象，然后保存到一个数组中。
在调用
animate(with:, timePerFrame:)
方法创建动画动作时，我们将这个数组以
及一个平均帧播放时间作为参数传递给它。假设我们需要让动画以
30
帧
/
秒的速
度播放，则每帧的平均播放时间为
1/30
秒（
0.033
秒
/
帧）。
要获得
SKTexture
对
象以便渲染，我们可以用
SKTexture
的
SKTexture(imageNamed:)
初始化方法，也可以通过包含它们的纹理图集来获得。我们曾经在本章
6.11
节中
讨论过纹理图集，这是一种将帧动画进行集中管理的绝好办法。它不但节省内存，
而且能保证动画中的每一帧都不会被丢失，当动画加载比较多的帧时游戏不会因此
出现短暂卡顿。
6.19
视差滚动
问题
通过
Sprite Kit
，我们想显示一个
2D
场景，但同时也要具有一定的深度，即当镜头
移动时，远处的物体比近处的物体要移动得慢。
解决方案
实现视差滚动的方法依赖于游戏的细节。在这个答案里，我们会创建一个包含
4
个
部分的场景，根据距离远近的不同，依次为：
•
一条山间土路。
•
旁边的山峦。
•
远处的山峦。
•
天空。
2D
图形和
Sprite Kit
｜
209
场景的最终效果如图
6-5
所示（下面这张图片不会滚动，除非你拥有魔法 ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.