Rasagar/Library/PackageCache/com.unity.render-pipelines.universal/Documentation~/render-graph-unsafe-pass.md

---
uid: urp-render-graph-unsafe-pass
---
# Use Compatibility Mode APIs in render graph render passes

You can use the render graph `AddUnsafePass` API to use Compatibility Mode APIs such as `SetRenderTarget` in render graph system render passes.

If you use the `AddUnsafePass` API, the following applies:

- You can't use the `SetRenderAttachment` method in the `RecordRenderGraph` method. Use `SetRenderTarget` in the `SetRenderFunc` method instead.
- Rendering might be slower because URP can't optimize the render pass. For example, if your render pass writes to the active color buffer, URP can't detect if a later render pass writes to the same buffer. As a result, URP can't merge the two render passes, and the GPU transfers the buffer in and out of memory unnecessarily.

## Create an unsafe render pass

To create an unsafe render pass, follow these steps:

1. In your `RecordRenderGraph` method, use the `AddUnsafePass` method instead of the `AddRasterRenderPass` method.

    For example:

    ```csharp
    using (var builder = renderGraph.AddUnsafePass<PassData>("My unsafe render pass", out var passData))
    ```

2. When you call the `SetRenderFunc` method, use the `UnsafeGraphContext` type instead of `RasterGraphContext`.

    For example:

    ```csharp
    builder.SetRenderFunc(
        (PassData passData, UnsafeGraphContext context) => ExecutePass(passData, context)
    );
    ```

3. If your render pass writes to a texture, you must add the texture as a field in your pass data class.

    For example:

    ```csharp
    private class PassData
    {
        internal TextureHandle textureToWriteTo;
    }
    ```

4. If your render pass writes to a texture, you must also set the texture as writeable using the `UseTexture` method.

    For example:

    ```csharp
    builder.UseTexture(passData.textureToWriteTo, AccessFlags.Write);
    ```

You can now use Compatibility Mode APIs in your `SetRenderFunc` method.

## Example

The following example uses the Compatibility Mode `SetRenderTarget` API to set the render target to the active color buffer during the render pass, then draw objects using their surface normals as colors.

```csharp
using UnityEngine;
using UnityEngine.Rendering.RenderGraphModule;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

public class DrawNormalsToActiveColorTexture : ScriptableRendererFeature
{

    DrawNormalsPass unsafePass;

    public override void Create()
    {
        unsafePass = new DrawNormalsPass();
        unsafePass.renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing;
    }

    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
    {
        renderer.EnqueuePass(unsafePass);
    }

    class DrawNormalsPass : ScriptableRenderPass
    {
        private class PassData
        {
            internal TextureHandle activeColorBuffer;
            internal TextureHandle cameraNormalsTexture;
        }

        public override void RecordRenderGraph(RenderGraph renderGraph, ContextContainer frameContext)
        {
            using (var builder = renderGraph.AddUnsafePass<PassData>("Draw normals", out var passData))
            {
                // Make sure URP generates the normals texture
                ConfigureInput(ScriptableRenderPassInput.Normal);

                // Get the frame data
                UniversalResourceData resourceData = frameContext.Get<UniversalResourceData>();

                // Add the active color buffer to our pass data, and set it as writeable 
                passData.activeColorBuffer = resourceData.activeColorTexture;
                builder.UseTexture(passData.activeColorBuffer, AccessFlags.Write);                

                // Add the camera normals texture to our pass data 
                passData.cameraNormalsTexture = resourceData.cameraNormalsTexture;
                builder.UseTexture(passData.cameraNormalsTexture);

                builder.AllowPassCulling(false);

                builder.SetRenderFunc((PassData data, UnsafeGraphContext context) => ExecutePass(data, context));
            }
        }

        static void ExecutePass(PassData passData, UnsafeGraphContext context)
        {
            // Create a command buffer for a list of rendering methods
            CommandBuffer unsafeCommandBuffer = CommandBufferHelpers.GetNativeCommandBuffer(context.cmd);

            // Add a command to set the render target to the active color buffer so URP draws to it
            context.cmd.SetRenderTarget(passData.activeColorBuffer);

            // Add a command to copy the camera normals texture to the render target
            Blitter.BlitTexture(unsafeCommandBuffer, passData.cameraNormalsTexture, new Vector4(1, 1, 0, 0), 0, false);
        }

    }

}
```

For another example, refer to the example called **UnsafePass** in the [Universal Render Pipeline (URP) package samples](package-samples.md).