Built-in shader helper functions //内置的着色器辅助函数

Built-in shader helper functions 内置的着色器辅助函数

Unity has a number of built-in utility functions designed to make writing shaders simpler and easier.

Unity有许多内置的实用功能，可以让编写着色器变得更简单和简单。

Functions declared in UnityCG.cginc 函数中声明UnityCG.cginc

See Built-in shader include files for an overview of shader include files provided with Unity.

查看内置的着色器包括文件，用于对着色器的概述，其中包括提供Unity的文件。

Vertex transformation functions in UnityCG.cginc 在unitycg.cginc中的顶点转换函数

Function: 函数	Description: 描述
float4 UnityObjectToClipPos(float3 pos)	Transforms a point from object space to the camera’s clip space in homogeneous coordinates. This is the equivalent of mul(UNITY_MATRIX_MVP, float4(pos, 1.0)), and should be used in its place 将一个点从物体空间转换为在齐次坐标下的摄像机的剪辑空间。这相当于mul(UNITY_MATRIX_MVP, float4(pos, 1.0))，应该在它的位置使用。.
float3 UnityObjectToViewPos(float3 pos)	Transforms a point from object space to view space. This is the equivalent of mul(UNITY_MATRIX_MV, float4(pos, 1.0)).xyz, and should be used in its place 将一个点从对象空间转换为视图空间。这相当于mul(UNITY_MATRIX_MV, float4(pos, 1.0)))。xyz，应该在它的位置使用。.

Generic helper functions in UnityCG.cginc 

通用辅助函数在unitycg.cginc中

Function: 函数	Description: 描述
float3 WorldSpaceViewDir (float4 v)	Returns world space direction (not normalized) from given object space vertex position towards the camera 从给定的物体空间顶点位置向相机返回世界空间方向(不规格化)。.
float3 ObjSpaceViewDir (float4 v)	Returns object space direction (not normalized) from given object space vertex position towards the camera 从给定的对象空间顶点位置向摄像机返回对象空间方向(不规格化)。.
float2 ParallaxOffset (half h, half height, half3 viewDir)	calculates UV offset for parallax normal mapping 计算视差贴图的UV偏移量。.
fixed Luminance (fixed3 c)	Converts color to luminance (grayscale) 把颜色转换成亮度(灰度)。.
fixed3 DecodeLightmap (fixed4 color)	Decodes color from Unity lightmap (RGBM or dLDR depending on platform) 从unity的lightmap(RGBM或dLDR根据平台)来解码颜色。.
float4 EncodeFloatRGBA (float v)	Encodes [0..1) range float into RGBA color, for storage in low precision render target 编码0.1)范围浮动到RGBA颜色，用于低精度渲染目标的存储。.
float DecodeFloatRGBA (float4 enc)	Decodes RGBA color into a float 将RGBA颜色转换为一个浮点数。.
float2 EncodeFloatRG (float v)	Encodes [0..1) range float into a float2 编码0.1)范围浮动到浮动2。.
float DecodeFloatRG (float2 enc)	Decodes a previously-encoded RG float 解码先前编码的RG浮点数。.
float2 EncodeViewNormalStereo (float3 n)	Encodes view space normal into two numbers in 0..1 range. 将视图空间的正常值编码为0。1范围。\
float3 DecodeViewNormalStereo (float4 enc4)	Decodes view space normal from enc4.xy 解码从enc4.xy中正常的空间。.

Forward rendering helper functions in UnityCG.cginc 在unitycg.cginc中向前呈现帮助函数

These functions are only useful when using forward rendering (ForwardBase or ForwardAdd pass types).

这些函数只有在使用向前呈现时才有用(向前推进或向前添加传递类型)。

Function: 函数	Description: 描述
float3 WorldSpaceLightDir (float4 v)	Computes world space direction (not normalized) to light, given object space vertex position 计算世界空间方向(不规格化)到光，给定物体空间顶点位置。.
float3 ObjSpaceLightDir (float4 v)	Computes object space direction (not normalized) to light, given object space vertex position 计算对象空间方向(不规范化)到光，给定对象空间顶点位置。.
float3 Shade4PointLights (...)	Computes illumination from four point lights, with light data tightly packed into vectors. Forward rendering uses this to compute per-vertex lighting 从四个点光源计算照明，将光数据紧密地压缩到矢量中。向前渲染利用这个来计算每个顶点的照明。.

Screen-space helper functions in UnityCG.cginc 在unitycg.cginc中的屏幕空间助手函数

The following functions are helpers to compute coordinates used for sampling screen-space textures. They return 

float4

 where the final coordinate to sample texture with
can be computed via perspective division (for example 

xy/w

).

下面的函数是用来计算用于采样屏幕空间纹理的坐标的辅助工具。它们返回漂浮的地方，在那里，最终的坐标可以通过透视划分(例如xy/w)来计算纹理。

The functions also take care of platform differences in render texture coordinates.

这些函数还可以处理渲染纹理坐标的平台差异。

Function: 函数	Description: 描述
float4 ComputeScreenPos (float4 clipPos)	Computes texture coordinate for doing a screenspace-mapped texture sample. Input is clip space position omputes的纹理坐标用于做一个屏幕空间的纹理采样。输入是剪辑空间位置。.
float4 ComputeGrabScreenPos (float4 clipPos)	Computes texture coordinate for sampling a GrabPass texure. Input is clip space position 计算纹理坐标，以对一个GrabPass材质进行采样。输入是剪辑空间位置。.

Vertex-lit helper functions in UnityCG.cginc 在unitycg.cginc中，vertexlit的助手函数

These functions are only useful when using per-vertex lit shaders (“Vertex” pass type).

当使用每个顶点的光照着色器(“顶点”传递类型)时，这些函数才有用。

Function:	Description:
float3 ShadeVertexLights (float4 vertex, float3 normal)	Computes illumination from four per-vertex lights and ambient, given object space position & normal 根据给定的物体空间位置和正常情况，计算每个顶点灯光和环境的光照。.