Restrict a render pass to a scene area in URP

To restrict a render pass to a specific area of a scene, add a volume to the scene, then add code to your render pass and your shader to check if the camera is inside the volume.

Follow these steps:

Update your shader code to enable or disable your custom rendering effect based on a Boolean value.

For example, add the following code to your shader:

Pass
{
    ...

    // Add a variable to enable or disable your custom rendering effect
    float _Enabled;

    ...

    float4 Frag(Varyings input) : SV_Target0
    {
        ...

        // Return the color with the effect if the variable is 1, or the original color if the variable is 0
        if (_Enabled == 1){
            return colorWithEffect;
        } else {
            return originalColor;
        }
    }
}

Create a script that implements the VolumeComponent class. This creates a volume override component that you can add to a volume.
```
using UnityEngine;
using UnityEngine.Rendering;

public class MyVolumeOverride : VolumeComponent
{
}
```
In the Hierarchy window, select the Add (+) button, then select GameObject > Volume > Box Volume.
In the Inspector window for the new box volume, under Volume, select New to create a new volume profile.
Select Add override, then select your volume override component, for example My Volume Override.

Add a property to the volume override script. Unity adds the property in the Inspector window of the volume override.

For example:

public class MyVolumeOverride : VolumeComponent
{
    // Add an 'Effect Enabled' checkbox to the Volume Override, with a default value of true.
    public BoolParameter effectEnabled = new BoolParameter(true);
}

In your custom pass, use the GetComponent API to get the volume override component and check the value of the property.

For example:

class myCustomPass : ScriptableRenderPass
{

    ...

    public void Setup(Material material)
    {
        // Get the volume override component
        MyVolumeOverride myOverride = VolumeManager.instance.stack.GetComponent<MyVolumeOverride>();

        // Get the value of the 'Effect Enabled' property
        bool effectStatus = myOverride.effectEnabled.overrideState ? myOverride.effectEnabled.value : false;
    }
}

Pass the value of the property to the variable you added to the shader code.

For example:

class myCustomPass : ScriptableRenderPass
{

    ...

    public void Setup(Material material)
    {
        MyVolumeOverride myOverride = VolumeManager.instance.stack.GetComponent<MyVolumeOverride>();
        bool effectStatus = myOverride.effectEnabled.overrideState ? myOverride.effectEnabled.value : false;

        // Pass the value to the shader
        material.SetFloat("_Enabled", effectStatus ? 1 : 0);
    }
}

Your custom rendering effect is now enabled when the camera is inside the volume, and disabled when the camera is outside the volume.

Restrict a render pass to a scene area in URP

Additional resources