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-camera

Use the camera in a custom URP shader

To use the camera 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 | |-|-|-| | GetCameraPositionWS | float3 GetCameraPositionWS() | Returns the world space position of the camera. | | GetScaledScreenParams | float4 GetScaledScreenParams() | Returns the width and height of the screen in pixels. | | GetViewForwardDir | float3 GetViewForwardDir() | Returns the forward direction of the view in world space. | | IsPerspectiveProjection | bool IsPerspectiveProjection() | Returns true if the camera projection is set to perspective. | | LinearDepthToEyeDepth | half LinearDepthToEyeDepth(half linearDepth) | Converts a linear depth buffer value to view depth. Refer to Cameras and depth textures for more information. | | TransformScreenUV | void TransformScreenUV(inout float2 screenSpaceUV) | Flips the y coordinate of the screen space position, if Unity uses an upside-down coordinate space. You can also input both a uv, and the screen height as a float, so the method outputs the position scaled to the screen size in pixels. |

Example

The following URP shader draws object surfaces with colors that represent the direction from the surface to the camera.

Shader "Custom/DirectionToCamera"
{
    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 viewDirection : TEXCOORD2;
            };

            Varyings vert(Attributes IN)
            {
                Varyings OUT;

                // Get the positions of the vertex in different coordinate spaces
                VertexPositionInputs positions = GetVertexPositionInputs(IN.positionOS);
                OUT.positionCS = positions.positionCS;

                // Get the direction from the vertex to the camera, in world space
                OUT.viewDirection = GetCameraPositionWS() - positions.positionWS.xyz;

                return OUT;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                // Set the fragment color to the direction vector
                return float4(IN.viewDirection, 1);
            }
            ENDHLSL
        }
    }
}

Additional resources

• Cameras in URP
• Writing custom shaders
• Upgrade custom shaders for URP compatibility
• HLSL in Unity