着色器

This type of node is used to describe a UUSL shader in an ULON-based material file. Currently, the engine supports Vertex, Control, Evaluate, Geometry, Fragment, and Compute shaders.这种类型的节点用于描述基于 ULON 的材质文件中的 UUSL 着色器。目前，引擎支持 Vertex, Control, Evaluate, Geometry, Fragment 和 Compute 着色器。

The syntax is the following:语法如下：

Shader name =
#{
	// UUSL code
#}

As a node's value you must specify a UUSL-based code enclosed in "#{" and "#}".作为节点的值，您必须指定UUSL基于 "#{" 和 "#}" 的代码。

See the SDK/data/core/shaders/common/ directory for the list of headers implementing common shaders' functions which can be included and used in custom shaders. To start writing UUSL shaders, include the common header:请参阅 SDK/data/core/shaders/common/ 目录以获取实现通用着色器功能的标头列表，这些功能可以包含在自定义着色器中并使用。要开始编写 UUSL 着色器，请包含公共标头：

#include <core/shaders/common/common.h>

The following types of shaders corresponding to their counterparts in different graphic APIs are available:以下类型的着色器对应于不同图形 API 中的对应物：

The shader node is usually used as a shader value for the Pass node.着色器节点通常用作 Pass 节点的着色器值。

Shader shader_a =
#{
	// some UUSL code
#}

Pass ambient
{
	Vertex = shader_a
	Fragment = shader_a
}

The advantages of this shader setup method are:这种着色器设置方法的优点是：

• It reduces the amount of identical code.它减少了相同代码的数量。
• One shader code can be used in different render passes.一个着色器代码可用于不同的渲染通道。

On the other hand, it is not the best approach for large shaders. Use includes for these cases:另一方面，它不是大型着色器的最佳方法。在这些情况下使用 includes：

1. Write different shaders in separate files and then specify their paths as shader values in the pass:
   shaders/a.vert (UUSL)

   // some UUSL code

   shaders/b.frag (UUSL)

   // some UUSL code

   Source code (ULON)

   Pass deferred 
   {
   	Vertex = "shaders/a.vert"
   	Fragment = "shaders/b.frag"
   }

   在单独的文件中编写不同的着色器，然后在 pass 中将它们的路径指定为着色器值：
   shaders/a.vert (UUSL)

   // some UUSL code

   shaders/b.frag (UUSL)

   // some UUSL code

   Source code (ULON)

   Pass deferred 
   {
   	Vertex = "shaders/a.vert"
   	Fragment = "shaders/b.frag"
   }

2. Include the code of a different shader by using the marker: #shader shader_name.
   Source code (ULON)

   Shader a = 
   #{
           // shader code A
   }#
   
   Shader b = 
   #{
           // shader code B
           #shader a
   }#
   
   // the result shader b will look like this: 
   Shader b = 
   #{
           // shader code B
           // shader code A
   #}

   使用标记包含不同着色器的代码：#shader shader_name。
   Source code (ULON)

   Shader a = 
   #{
           // shader code A
   }#
   
   Shader b = 
   #{
           // shader code B
           #shader a
   }#
   
   // the result shader b will look like this: 
   Shader b = 
   #{
           // shader code B
           // shader code A
   #}