To use shadows in a custom Universal Render PipelineA series of operations that take the contents of a Scene, and displays them on a screen. Unity lets you choose from pre-built render pipelines, or write your own. More info
See in Glossary (URP) shaderA program that runs on the GPU. More info
See in Glossary, follow these steps:
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
inside the HLSLPROGRAM
in your shader file. The Core.hlsl
file imports the Shadows.hlsl
and RealtimeLights.hlsl
files.Use these methods to convert positions to shadow map positions.
Method | Syntax | Description |
---|---|---|
GetShadowCoord |
float4 GetShadowCoord(VertexPositionInputs vertexInputs) |
Converts a vertex position into shadow space. Refer to Transform positions in a custom URP shader for information on the VertexPositionInputs struct. |
TransformWorldToShadowCoord |
float4 TransformWorldToShadowCoord(float3 positionInWorldSpace) |
Converts a position in world space to shadow space. |
The following methods calculate shadows using shadow maps. To use these methods, follow these steps first:
ShadowCaster
shader pass, for example objects that use the Universal Render Pipeline/Lit
shader.#pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
to your shader, so it can access the shadow map for the main light.#pragma multi_compile _ _ADDITIONAL_LIGHT_SHADOWS
to your shader, so it can access the shadow maps for additional lights.Method | Syntax | Description |
---|---|---|
GetMainLight |
Light GetMainLight(float4 shadowCoordinates) |
Returns the main light in the scene, with a shadowAttenuation value based on whether the position at the shadow coordinates is in shadow. |
ComputeCascadeIndex |
half ComputeCascadeIndex(float3 positionInWorldSpace) |
Returns the index of the shadow cascade at the position in world space. Refer to Shadow cascades for more information. |
MainLightRealtimeShadow |
half MainLightRealtimeShadow(float4 shadowCoordinates) |
Returns the shadow value from the main shadow map at the coordinates. Refer to Shadow mapping for more information. |
AdditionalLightRealtimeShadow |
half AdditionalLightRealtimeShadow(int lightIndex, float3 positionInWorldSpace) |
Returns the shadow value from the additional light shadow map at the position in world space. |
GetMainLightShadowFade |
half GetMainLightShadowFade(float3 positionInWorldSpace) |
Returns the amount to fade the shadow from the main light, based on the distance between the position and the cameraA component which creates an image of a particular viewpoint in your scene. The output is either drawn to the screen or captured as a texture. More info See in Glossary. |
GetAdditionalLightShadowFade |
half GetAdditionalLightShadowFade(float3 positionInWorldSpace) |
Returns the amount to fade the shadow from additional lights, based on the distance between the position and the camera. |
ApplyShadowBias |
float3 ApplyShadowBias(float3 positionInWorldSpace, float3 normalWS, float3 lightDirection) |
Adds shadow bias to the position in world space. Refer to Shadow troubleshooting for more information. |
The following URP shader draws simple shadows onto a surface.
To generate shadows, make sure there are objects in your scene that have a ShadowCaster
shader pass, for example objects that use the Universal Render Pipeline/Lit
shader.
Shader "Custom/SimpleShadows"
{
SubShader
{
Tags { "RenderType" = "AlphaTest" "RenderPipeline" = "UniversalPipeline" }
Pass
{
HLSLPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
struct Attributes
{
float4 positionOS : POSITION;
};
struct Varyings
{
float4 positionCS : SV_POSITION;
float4 shadowCoords : TEXCOORD3;
};
Varyings vert(Attributes IN)
{
Varyings OUT;
OUT.positionCS = TransformObjectToHClip(IN.positionOS.xyz);
// Get the VertexPositionInputs for the vertex position
VertexPositionInputs positions = GetVertexPositionInputs(IN.positionOS.xyz);
// Convert the vertex position to a position on the shadow map
float4 shadowCoordinates = GetShadowCoord(positions);
// Pass the shadow coordinates to the fragment shader
OUT.shadowCoords = shadowCoordinates;
return OUT;
}
half4 frag(Varyings IN) : SV_Target
{
// Get the value from the shadow map at the shadow coordinates
half shadowAmount = MainLightRealtimeShadow(IN.shadowCoords);
// Set the fragment color to the shadow value
return shadowAmount;
}
ENDHLSL
}
}
}
Did you find this page useful? Please give it a rating:
Thanks for rating this page!
What kind of problem would you like to report?
Thanks for letting us know! This page has been marked for review based on your feedback.
If you have time, you can provide more information to help us fix the problem faster.
Provide more information
You've told us this page needs code samples. If you'd like to help us further, you could provide a code sample, or tell us about what kind of code sample you'd like to see:
You've told us there are code samples on this page which don't work. If you know how to fix it, or have something better we could use instead, please let us know:
You've told us there is information missing from this page. Please tell us more about what's missing:
You've told us there is incorrect information on this page. If you know what we should change to make it correct, please tell us:
You've told us this page has unclear or confusing information. Please tell us more about what you found unclear or confusing, or let us know how we could make it clearer:
You've told us there is a spelling or grammar error on this page. Please tell us what's wrong:
You've told us this page has a problem. Please tell us more about what's wrong:
Thank you for helping to make the Unity documentation better!
Your feedback has been submitted as a ticket for our documentation team to review.
We are not able to reply to every ticket submitted.