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Unity Engine

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Unity Engine

Transform positions in a custom URP shader

Transform vertex, fragment, normal and tangent positions between coordinate spaces.
阅读时间2 分钟最后更新于 1 个月前
To transform positions in a custom Universal Render Pipeline (URP) shader, follow these steps:
  1. Add 
    #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
    inside the 
    HLSLPROGRAM
    in your shader file. The 
    Core.hlsl
    file imports the 
    ShaderVariablesFunction.hlsl
    file.
  2. Use one of the following methods from the 
    ShaderVariablesFunction.hlsl
    file.

Method

Syntax

Description

GetNormalizedScreenSpaceUV
float2 GetNormalizedScreenSpaceUV(float2 positionInClipSpace)
Converts a position in clip space to screen space.
GetObjectSpaceNormalizeViewDir
half3 GetObjectSpaceNormalizeViewDir(float3 positionInObjectSpace)
Converts a position in object space to the normalized direction towards the viewer.
GetVertexNormalInputs
VertexNormalInputs GetVertexNormalInputs(float3 normalInObjectSpace)
Converts the normal of a vertex in object space to a tangent, bitangent, and normal in world space. You can also input both the normal and a 
float4
tangent in object space.
GetVertexPositionInputs
VertexPositionInputs GetVertexPositionInputs(float3 positionInObjectSpace)
Converts the position of a vertex in object space to positions in world space, view space, clip space, and normalized device coordinates.
GetWorldSpaceNormalizeViewDir
half3 GetWorldSpaceNormalizeViewDir(float3 positionInWorldSpace)
Returns the direction from a position in world space to the viewer, and normalizes the direction.
GetWorldSpaceViewDir
float3 GetWorldSpaceViewDir(float3 positionInWorldSpace)
Returns the direction from a position in world space to the viewer.

Structs

VertexPositionInputs

Use the GetVertexPositionInputs method to get this struct.

Field

Description

float3 positionWS
The position in world space.
float3 positionVS
The position in view space.
float4 positionCS
The position in clip space.
float4 positionNDC
The position as normalized device coordinates (NDC).

VertexNormalInputs

Use the 
GetVertexNormalInputs
method to get this struct.

Field

Description

real3 tangentWS
The tangent in world space.
real3 bitangentWS
The bitangent in world space.
float3 normalWS
The normal in world space.

Example

The following URP shader draws object surfaces with colors that represent their position in screen space.
Shader "Custom/ScreenSpacePosition"{    SubShader    {        Tags { "RenderType" = "Opaque" "RenderPipeline" = "UniversalPipeline" }        Pass        {            HLSLPROGRAM            #pragma vertex vert            #pragma fragment frag            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"            struct Attributes            {                float4 positionOS : POSITION;                float2 uv: TEXCOORD0;            };            struct Varyings            {                float4 positionCS  : SV_POSITION;                float2 uv: TEXCOORD0;                float3 positionWS : TEXCOORD2;            };            Varyings vert(Attributes IN)            {                Varyings OUT;                OUT.positionCS = TransformObjectToHClip(IN.positionOS.xyz);                // Get the position of the vertex in different spaces                VertexPositionInputs positions = GetVertexPositionInputs(IN.positionOS);                // Set positionWS to the world space position of the vertex                OUT.positionWS = positions.positionWS.xyz;                return OUT;            }            half4 frag(Varyings IN) : SV_Target            {                // Set the fragment color to the world space position vector                return float4(IN.positionWS.xy, 0, 1);            }            ENDHLSL        }    }}

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