HX-PGS-AIM-IOS/Library/PackageCache/com.unity.render-pipelines..../Documentation~/use-built-in-shader-methods...

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uid: urp-docfx-use-built-in-shader-methods-transformations

Transform positions in a custom URP shader

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 GetVertexNormalInputs 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 screen space position of the vertex
                OUT.positionWS = positions.positionWS.xyz;

                return OUT;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                // Set the fragment color to the screen space position vector
                return float4(IN.positionWS.xy, 0, 1);
            }
            ENDHLSL
        }
    }
}

Additional resources

• Writing custom shaders
• Upgrade custom shaders for URP compatibility
• HLSL in Unity
• Shader semantics