UnityGame/Library/PackageCache/com.unity.shadergraph/Documentation~/Calculate-Level-Of-Detail-Texture-2D-Node.md

# Calculate Level Of Detail Texture 2D node

The Calculate Level of Detail Texture 2D node takes an input **Texture 2D** and outputs the mip level of a Texture sample. This node is useful in situations where you need to know the mip level of a Texture, such as when you might want to modify the mip level before sampling in your shader.

![An image of the Graph window, that shows a Calculate Level of Detail Texture 2D node.](images/sg-calculate-level-detail-Texture-2d-node.png)

The Calculate Level of Detail Texture 2D node also has a clamped and unclamped mode:

- **Clamped**: The node clamps the returned mip level to the actual mips available on the Texture. The node uses the [CalculateLevelOfDetail](https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-calculate-lod) HLSL intrinsic function. Use this mode when you want to know which mip to sample your Texture from and restrict the result to an existing mip.

- **Unclamped**: The node returns the ideal mip level, based on an idealized Texture with all its mips present. The node uses the [CalculateLevelOfDetailUnclamped](https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-calculate-lod-unclamped) HLSL intrinsic function. Use this mode when you need a more generic value for your mip level.

For example, a Texture might only have 3 mips: a 64×64 mip, a 32×32 mip, and a 16×16 mip. When you use the Calculate Level Of Detail Texture 2D node in its **Clamped** mode, the node restricts the **LOD** output to one of the 3 mips on the Texture, even if the ideal mip level might be a smaller resolution, such as an 8×8 version. In its **Unclamped** mode, the node outputs the ideal 8×8 mip level, even though it doesn't exist on the Texture.

> [!NOTE]
> On platforms where these HLSL functions don't exist, Shader Graph determines an appropriate approximation to use, instead.

## Create Node menu category

The Calculate Level of Detail Texture 2D node is under the **Input** > **Texture** category in the Create Node menu.

## Compatibility

The Calculate Level of Detail Texture 2D [!include[nodes-compatibility-all](./snippets/nodes-compatibility-all.md)]    <!-- ALL PIPELINES INCLUDE  -->

The Calculate Level of Detail Texture 2D [!include[nodes-fragment-only](./snippets/nodes-fragment-only.md)]       <!-- FRAGMENT ONLY INCLUDE  -->

## Inputs

The Calculate Level of Detail Texture 2D [!include[nodes-inputs](./snippets/nodes-inputs.md)]

| **Name**     | **Type**      | **Binding** | **Description**  |
| :---         | :------       |  :------    |   :----------    |
| **Texture**  | Texture 2D    |    None     | The Texture to use in the mip level calculation. |
| **UV**       | Vector 2      |    UV       | The UV coordinate to use to calculate the Texture's mip level.        |
| **Sampler**  | SamplerState  |    None     | The Sampler State and corresponding settings to use to calculate the Texture's mip level.   |

## Controls

The Calculate Level of Detail Texture 2D [!include[nodes-single-control](./snippets/nodes-single-control.md)]

| **Name**     | **Type** | **Options** | **Description**  |
| :---         | :---     | :------     |  :----------     |
| **Clamp**    | Toggle   | True, False | When enabled, Shader Graph clamps the output mip level to the actual mips present on the provided **Texture** input. When disabled, Shader Graph returns an ideal mip level, based on an idealized Texture with all its mips present. |


## Outputs

The Calculate Level of Detail Texture 2D [!include[nodes-single-output](./snippets/nodes-single-output.md)] <!-- SINGLE OUTPUT PORT INCLUDE -->

| **Name** | **Type** | **Description** |
| :------  | :------- | :-------------  |
| **LOD**  | Float    |  The final calculated mip level of the Texture. |

## Example graph usage

In the following example, a Calculate Level of Detail Texture 2D node calculates the mip level of the **Leaves_Albedo** Texture for a set of UV coordinates and a specific Sampler State. It sends the calculated mip level for the Texture to the **LOD** input port on a Sample Texture 2D LOD node, which samples the same Texture:

![An image of the Graph window, that displays a Texture 2D asset node connected to a Calculate Level of Detail Texture 2D node. The node sends the calculated mip level as an input to the LOD input port on a Sample Texture 2D LOD node.](images/sg-calculate-level-detail-Texture-2d-node-example.png)


## Related nodes

<!-- OPTIONAL. Any nodes that may be related to this node in some way that's worth mentioning -->

[!include[nodes-related](./snippets/nodes-related.md)] Calculate Level of Detail Texture 2D node:

- [Sample Texture 2D LOD node](Sample-Texture-2D-LOD-Node.md)
- [Sampler State node](Sampler-State-Node.md)
- [Gather Texture 2D node](Gather-Texture-2D-Node.md)
- [Texture 2D Asset node](Texture-2D-Asset-Node.md)