# Sample motion vectors in a shader in URP

> Request the motion vector texture as an input in a custom shader.

Any `ScriptableRenderPass` implementation can request the motion vector texture as input. To do that, add the `ScriptableRenderPassInput.Motion` flag in the [ScriptableRenderPass.ConfigureInput](https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@17.2/api/UnityEngine.Rendering.Universal.ScriptableRenderPass.html#UnityEngine_Rendering_Universal_ScriptableRenderPass_ConfigureInput_UnityEngine_Rendering_Universal_ScriptableRenderPassInput_) method in the [AddRenderPasses](https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@17.2/api/UnityEngine.Rendering.Universal.ScriptableRendererFeature.html#UnityEngine_Rendering_Universal_ScriptableRendererFeature_AddRenderPasses_UnityEngine_Rendering_Universal_ScriptableRenderer_UnityEngine_Rendering_Universal_RenderingData__) callback of your custom Renderer Feature. If no other effect in the frame is using motion vectors, setting this input flag forces the URP renderer to inject the motion vector render pass into the frame.

To sample the motion vector texture in your shader pass, declare the shader resource for it in the `HLSLPROGRAM` section:

```lang-cpp
    TEXTURE2D_X(_MotionVectorTexture);
    SAMPLER(sampler_MotionVectorTexture);
```

To perform the sampling, use the following macro:

```lang-cpp
    SAMPLE_TEXTURE2D_X(_MotionVectorTexture, sampler_MotionVectorTexture, uv);
```

The `_X` postfix ensures that the texture is correctly declared and sampled when targeting XR platforms.