Using Metal to Draw a View‘s Contents用Metal绘制视图内容

Using Metal to Draw a View’s Contents

时间：2021-9-25
分类：Xcode，Metal开发，
针对人群：初学者，具备初级英语能力
来源：XCode帮助文件
Create a MetalKit view and a render pass to draw the view’s contents.
创建一个MetalKit视图和一个渲染通道来绘制视图内容。

Overview

In this sample, you’ll learn the basics of rendering graphics content with Metal.
You’ll use the MetalKit framework框架 to create a view that uses Metal to draw the contents of the view. Then, you’ll encode commands for a render pass that erases the view to a background color.
在这个例子中，你将学习用Metal渲染图形内容的基本操作。你会用MetalKit框架来创建一个视图，用Metal来绘制视图的内容。然后，你编码命令给一个渲染通道来“擦除”掉视图的背景颜色。

• Note: MetalKit automates windowing system tasks, loads textures, and handles 3D model data. See [MetalKit][MetalKit] for more information.

Prepare a MetalKit View to Draw

MetalKit provides a class called [MTKView][MTKView], which is a subclass of [NSView][NSView] (in macOS) or [UIView][UIView] (in iOS and tvOS).
MTKView handles many of the details related相关联的细节 to getting the content you draw with Metal onto the screen.

An MTKView needs a reference引用（就是 C++中的指针） to a Metal device object in order to create resources internally, so your first step is to set the view’s device property to an existing [MTLDevice][MTLDevice].

_view.device = MTLCreateSystemDefaultDevice();

Other properties属性 on MTKView allow you to control its behavior行为. To erase the contents of the view to a solid background color, you set its clearColor