Rasagar/Library/PackageCache/com.unity.render-pipelines.universal/Documentation~/use-built-in-shader-methods-camera.md

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urp-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