《Unity着色器圣经》3.1.0 | MPD枚举

目录索引

【人工翻译】《Unity着色器圣经》全书目录

3小时前

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译文

枚举（Enum）跟关键词枚举（KeywordEnum）很像，不同之处在于枚举可以定义一个 “值/id “作为参数，并传递到着色器命令中使用，从而从检查器中动态更改其功能。

声明语法如下所示：

[Enum(valor, id_00, valor, id_01, etc … )] 
    _PropertyName ("Display Name", Float) = 0

枚举并不依赖着色器变体，它通过命令或函数进行声明。为了理解这个概念，让我们看看下面这个例子：

Shader "InspectorPath/shaderName" 
{ 
    Properties 
    { 
        // declare drawer 
        [Enum(Off, 0, Front, 1, Back, 2)] 
        _Face ("Face Culling", Float) = 0
    } 
    SubShader 
    { 
        // we use the property as a command 
        Cull [_Face] 
        Pass { … } 
    } 
}

在这个例子中，我们声明了一个叫做“_Face”的枚举属性，并定义了三个参数：关闭/0、前/1、后/2，接着我们将参数应用到了子着色器中的剔除（Cull）里，这样我们就可以在材质的检查器中更改我们想剔除的方向了。在后续的3.2.1小节中，我们会详细介绍剔除命令。

原文对照

This drawer is very similar to the KeywordEnum with the difference that it can define a “value/id” as an argument and pass this property to a command in our shader to change its functionality dynamically from the inspector.

Its syntax is as follows:

[Enum(valor, id_00, valor, id_01, etc … )] 
    _PropertyName ("Display Name", Float) = 0

Enums do not use shader variants but are declared by command or function. To understand their implementation, we will perform the following operation:

Shader "InspectorPath/shaderName" 
{ 
    Properties 
    { 
        // declare drawer 
        [Enum(Off, 0, Front, 1, Back, 2)] 
        _Face ("Face Culling", Float) = 0
    } 
    SubShader 
    { 
        // we use the property as a command 
        Cull [_Face] 
        Pass { … } 
    } 
}

As presented in this example, we declare a property type “Enum” called “_Face” and we pass as an argument the values: Off, 0, Front, 1, Back and 2. Then we add the property to the command “Cull” found in the SubShader; this way we can change the object face we want to render from the material inspector. In section 3.2.1 we will talk about the Cull command in detail.