> For the complete documentation index, see [llms.txt](https://docs.tenten.co/awesome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tenten.co/awesome/webgl/awesome-threejs-playground/docs/glsl/glsl-syntax.md).

# OpenGL GLSL 语法和函数详解

## 变量和数据类型

可用的数据类型只有4种：有符号整数，无符号整数，浮点数，布尔值。 OpenGL着色语言中没有指针和字符串或字符。返回值可以为void。

## 向量类型

所有4种基本数据类型都可以存储在二维、三维或者四维向量中：

OpenGL着色语言向量数据类型

| GLSL 类型           |                 描述 |
| ----------------- | -----------------: |
| vec2,vec3,vec4    |    2分量、3分量和4分量浮点向量 |
| ivec2,ivec3,ivec4 |    2分量、3分量和4分量整数向量 |
| uvec2,uvec3,uvec4 | 2分量、3分量和4分量无符号整数向量 |
| bvec2,vbec3,bvec4 |    2分量、3分量和4分量布尔向量 |

## 矩阵类型

矩阵类型只支持浮点数

OpenGL着色语言矩阵数据类型

| GLSL 类型     |   描述 |
| ----------- | ---: |
| mat2,mat2x2 | 两行两列 |
| mat3,mat3x3 | 三行三列 |
| mat4,mat4x4 | 四行四列 |
| mat2x3      | 三行两列 |
| mat2x4      | 四行两列 |
| mat3x2      | 两行三列 |
| mat3x4      | 四行三列 |
| mat4x2      | 两行四列 |
| mat4x3      | 三行四列 |

## 存储限定符

限定符用于将变量标记为输入变量、输出变量或常量。

变量存储限定符

| 限定符     |                              描述 |
| ------- | ------------------------------: |
| const   |       一个编译时常量，或者说是一个队函数来说为只读的参数 |
| in      |                 一个从以前的截断传递过来的变量 |
| in      | centroid 一个从以前的截断传递过来的变量，使用质心插值 |
| out     |       传递到下一个处理阶段或者在一个函数中指定一个返回值 |
| out     |      centroid 传递到下一个处理阶段，使用质心插值 |
| inout   |              一个读/写变量，只能用于局部函数参数 |
| uniform |       一个从客户端代码传递过来的变量，在顶点之间不做改变 |

## 着色器统一值

属性是每个顶点位置、表面法线和纹理坐标等都需要的，而统一值则用于为整个图元批次向保持不变的（统一（uniform）的）着色器传递数据。 创建一个统一值只需在变量声明开始时放置一个uniform关键词：

```
uniform float u_time; // 总是只读的
```

***

> [OpenGL GLSL 语法和函数详解](https://blog.csdn.net/jeffasd/article/details/78209965)


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