Built-in shader helper functions

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

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

Function:	Description:
`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.
`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.

Function:	Description:
`float3 WorldSpaceViewDir (float4 v)`	Returns world space direction (not normalized) from given object space vertex position towards the camera.
`float3 ObjSpaceViewDir (float4 v)`	Returns object space direction (not normalized) from given object space vertex position towards the camera.
`float2 ParallaxOffset (half h, half height, half3 viewDir)`	calculates UV offset for parallax normal mapping.
`fixed Luminance (fixed3 c)`	Converts color to luminance (grayscale).
`fixed3 DecodeLightmap (fixed4 color)`	Decodes color from Unity lightmap (RGBM or dLDR depending on platform).
`float4 EncodeFloatRGBA (float v)`	Encodes [0..1) range float into RGBA color, for storage in low precision render target.
`float DecodeFloatRGBA (float4 enc)`	Decodes RGBA color into a float.
`float2 EncodeFloatRG (float v)`	Encodes [0..1) range float into a float2.
`float DecodeFloatRG (float2 enc)`	Decodes a previously-encoded RG float.
`float2 EncodeViewNormalStereo (float3 n)`	Encodes view space normal into two numbers in 0..1 range.
`float3 DecodeViewNormalStereo (float4 enc4)`	Decodes view space normal from enc4.xy.

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

Function:	Description:
`float3 WorldSpaceLightDir (float4 v)`	Computes world space direction (not normalized) to light, given object space vertex position.
`float3 ObjSpaceLightDir (float4 v)`	Computes object space direction (not normalized) to light, given object space vertex position.
`float3 Shade4PointLights (...)`	Computes illumination from four point lights, with light data tightly packed into vectors. Forward rendering uses this to compute per-vertex lighting.

Function:	Description:
`float4 ComputeScreenPos (float4 clipPos)`	Computes texture coordinate for doing a screenspace-mapped texture sample. Input is clip space position. The function takes care of platform differences in render texture coordinates.
`float4 ComputeGrabScreenPos (float4 clipPos)`	Computes texture coordinate for sampling a GrabPass texure. Input is clip space position. The function takes care of platform differences in render texture coordinates.

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

Function:	Description:
`float3 ShadeVertexLights (float4 vertex, float3 normal)`	Computes illumination from four per-vertex lights and ambient, given object space position & normal.

Predefined Shader preprocessor macros

Built-in shader variables

Unity Manual