Upgrading to URP 15 (Unity 2023.1)

This page describes how to upgrade from an older version of the Universal Render Pipeline (URP) to URP 15 (Unity 2023.1).

For information on converting assets made for a Built-in Render Pipeline project to assets compatible with URP, refer to the page Render Pipeline Converter.

Upgrading from URP 13 (Unity 2022.1)

Two shader defines were removed

SHADER_QUALITY_LOW/MEDIUM/HIGH and SHADER_HINT_NICE_QUALITY shader defines were removed. If you used those defines in custom shaders, consider using SHADER_API_MOBILE or SHADER_API_GLES defines to replace SHADER_QUALITY_LOW/MEDIUM/HIGH.

Upgrading from URP 12 (Unity 2021.2)

Changes to ScriptableRenderer API behavior

Unity now issues an error when instances of ScriptableRendererFeature attempt to access render targets before they are allocated by the ScriptableRenderer class.

The ScriptableRendererFeature class has a new virtual function SetupRenderPasses which is called when render targets are allocated and ready to be used.

If your code uses the ScriptableRenderer.cameraColorTarget or the ScriptableRenderer.cameraDepthTarget property inside of the AddRenderPasses method override, you should move that implementation to the ScriptableRendererFeature.SetupRenderPasses method.

The calls to the ScriptableRenderer.EnqueuePass method should still happen in the AddRenderPasses method.

The following example shows how to change the code to use the new API.

Code with the old API:

public override void AddRenderPasses(ScriptableRenderer renderer,
                                    ref RenderingData renderingData)
{
    // The target is used before allocation
    m_CustomPass.Setup(renderer.cameraColorTarget);
     // Letting the renderer know which passes are used before allocation
    renderer.EnqueuePass(m_ScriptablePass);
}

Code with the new API:

public override void AddRenderPasses(ScriptableRenderer renderer,
                                        ref RenderingData renderingData)
{
    // Letting the renderer know which passes are used before allocation
    renderer.EnqueuePass(m_ScriptablePass);
}

public override void SetupRenderPasses(ScriptableRenderer renderer,
                                          in RenderingData renderingData)
{
    // The target is used after allocation
    m_CustomPass.Setup(renderer.cameraColorTarget);
}

The Universal Renderer is now using the RTHandle system

The Universal Renderer is now using the RTHandle system for its internal targets and in its internal passes.

All usages of the RenderTargetHandle struct are set as obsolete and the struct will be removed in the future.

The public interfaces ScriptableRenderer.cameraColorTarget and ScriptableRenderer.cameraDepthTarget are marked as obsolete. Replace them with ScriptableRenderer.cameraColorTargetHandle and ScriptableRenderer.cameraDepthTargetHandle respectively.

RTHandle targets do not use the CommandBuffer.GetTemporaryRT method and persist for more frames than the RenderTargetIdentifier structs. You cannot allocate RTHandle targets with the properties GraphicsFormat and DepthBufferBits set to any value except for 0. The cameraDepthTarget properties must be separate from the cameraColorTarget properties.

The following helper functions let you create and use temporary render target with the RTHandle system in a similar way as with the GetTemporaryRT method previously:

  • RenderingUtils.ReAllocateIfNeeded

  • ShadowUtils.ShadowRTReAllocateIfNeeded

If the render target does not change within the lifetime of the application, use the RTHandles.Alloc method to allocate an RTHandle target. This method is efficient since the code does not have to check if a render target should be allocated on each frame.

If the render target is a full screen texture, which means that its resolution matches or is a fraction of the resolution of the screen, use a scaling factor such as Vector2D.one to support dynamic scaling.

The following example shows how to change the code using the RenderTargetHandle API to use the new API.

Code with the old API:

public class CustomPass : ScriptableRenderPass
{
    RenderTargetHandle m_Handle;
    // With the old API, RenderTargetIdentifier might combine color and depth
    RenderTargetIdentifier m_Destination;

    public CustomPass()
    {
        m_Handle.Init("_CustomPassHandle");
    }

    public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
    {
        var desc = renderingData.cameraData.cameraTargetDescriptor;
        cmd.GetTemporaryRT(m_Handle.id, desc, FilterMode.Point);
    }

    public override void OnCameraCleanup(CommandBuffer cmd)
    {
        cmd.ReleaseTemporaryRT(m_Handle.id);
    }

    public void Setup(RenderTargetIdentifier destination)
    {
        m_Destination = destination;
    }

    public override void Execute(ScriptableRenderContext context,
                                    ref RenderingData renderingData)
    {
        CommandBuffer cmd = CommandBufferPool.Get();
        // Set the same target for color and depth
        ScriptableRenderer.SetRenderTarget(cmd, m_Destination, m_Destination, clearFlag,
                                              clearColor);
        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }
}

Code with the new API:

public class CustomPass : ScriptableRenderPass
{
    RTHandle m_Handle;
    // Then using RTHandles, the color and the depth properties must be separate
    RTHandle m_DestinationColor;
    RTHandle m_DestinationDepth;

    void Dispose()
    {
        m_Handle?.Release();
    }

    public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
    {
        var desc = renderingData.cameraData.cameraTargetDescriptor;
        // Then using RTHandles, the color and the depth properties must be separate
        desc.depthBufferBits = 0;
        RenderingUtils.ReAllocateIfNeeded(ref m_Handle, desc, FilterMode.Point,
                                         TextureWrapMode.Clamp, name: "_CustomPassHandle");
    }

    public override void OnCameraCleanup(CommandBuffer cmd)
    {
        m_DestinationColor = null;
        m_DestinationDepth = null;
    }

    public void Setup(RTHandle destinationColor, RTHandle destinationDepth)
    {
        m_DestinationColor = destinationColor;
        m_DestinationDepth = destinationDepth;
    }

    public override void Execute(ScriptableRenderContext context,
                                    ref RenderingData renderingData)
    {
        CommandBuffer cmd = CommandBufferPool.Get();
        ScriptableRenderer.SetRenderTarget(cmd, m_DestinationColor, m_DestinationDepth,
                                              clearFlag, clearColor);
        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }
}

Upgrading from URP 11.x.x

  • The Forward Renderer asset is renamed to the Universal Renderer asset. When you open an existing project in the Unity Editor containing URP 12, Unity updates the existing Forward Renderer assets to Universal Renderer assets.

  • The Universal Renderer asset contains the property Rendering Path that lets you select the Forward or the Deferred Rendering Path.

  • The method ClearFlag.Depth does not implicitly clear the Stencil buffer anymore. Use the new method ClearFlag.Stencil.

  • URP 12 and later implements the Render Pipeline Converter feature. This feature replaces the asset upgrade functions that were previously available at Edit > Render Pipeline > Universal Render Pipeline > Upgrade...

Upgrading from URP 10.0.x–10.2.x

  1. The file names of the following Shader Graph shaders were renamed. The new file names do not have spaces:
    Autodesk Interactive
    Autodesk Interactive Masked
    Autodesk Interactive Transparent

    If your code uses the Shader.Find() method to search for the shaders, remove spaces from the shader names, for example, Shader.Find("AutodeskInteractive).

Upgrading from URP 7.2.x and later releases

  1. URP 12.x.x does not support the package Post-Processing Stack v2. If your Project uses the package Post-Processing Stack v2, migrate the effects that use that package first.

DepthNormals Pass

Starting from version 10.0.x, URP can generate a normal texture called _CameraNormalsTexture. To render to this texture in your custom shader, add a Pass with the name DepthNormals. For an example, check the implementation in Lit.shader.

Screen Space Ambient Occlusion (SSAO)

URP 10.0.x implements the Screen Space Ambient Occlusion (SSAO) effect.

If you intend to use the SSAO effect with your custom shaders, consider the following entities related to SSAO:

  • The _SCREEN_SPACE_OCCLUSION keyword.

  • Input.hlsl contains the new declaration float2 normalizedScreenSpaceUV in the InputData struct.

  • Lighting.hlsl contains the AmbientOcclusionFactor struct with the variables for calculating indirect and direct occlusion:

    struct AmbientOcclusionFactor
{
    half indirectAmbientOcclusion;
    half directAmbientOcclusion;
};

  • Lighting.hlsl contains the following function for sampling the SSAO texture:

    half SampleAmbientOcclusion(float2 normalizedScreenSpaceUV)

  • Lighting.hlsl contains the following function:

    AmbientOcclusionFactor GetScreenSpaceAmbientOcclusion(float2
normalizedScreenSpaceUV)

To support SSAO in custom shader, add the DepthNormals Pass and the _SCREEN_SPACE_OCCLUSION keyword the the shader. For an example, check Lit.shader.

If your custom shader implements custom lighting functions, use the function GetScreenSpaceAmbientOcclusion(float2 normalizedScreenSpaceUV) to get the AmbientOcclusionFactor value for your lighting calculations.

Shadow Normal Bias

In 11.0.x the formula used to apply Shadow Normal Bias has been slightly fix in order to work better with punctual lights. As a result, to match exactly shadow outlines from earlier revisions, the parameter might to be adjusted in some scenes. Typically, using 1.4 instead of 1.0 for a Directional light is usually enough.

Intermediate Texture

In previous URP versions, URP performed the rendering via an intermediate Renderer if the Renderer had any active Renderer Features. On some platforms, this had significant performance implications. In this release, URP mitigates the issue in the following way: URP expects Renderer Features to declare their inputs using the ScriptableRenderPass.ConfigureInput method. The method provides the information that URP uses to determine automatically whether rendering via an intermediate texture is necessary.

For compatibility purpose, there is a new property Intermediate Texture in the Universal Renderer. If you select Always in the property, URP uses an intermediate texture. Selecting Auto enables the new behavior. Use the Always option only if a Renderer Feature does not declare its inputs using the ScriptableRenderPass.ConfigureInput method.

To ensure that existing projects work correctly, all existing Universal Renderer assets that were using any Renderer Features (excluding those included with URP) have the option Always selected in the Intermediate Texture property. Any newly created Universal Renderer assets have the option Auto selected.

Upgrading from URP 7.0.x-7.1.x

  1. Upgrade to URP 7.2.0 first. Refer to Upgrading to version 7.2.0 of the Universal Render Pipeline.

  2. URP 8.x.x does not support the package Post-Processing Stack v2. If your Project uses the package Post-Processing Stack v2, migrate the effects that use that package first.

Upgrading from LWRP to 12.x.x

  • There is no direct upgrade path from LWRP to URP 12.x.x. Follow the steps to upgrade LWRP to URP 11.x.x first, and then upgrade from URP 11.x.x to URP 12.x.x.