# GetShadowmaskChannelsFromLightIndices(BakeInput, int[])

> Retrieves the shadowmask channel assignments for specified mixed lights.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine.LightTransport](/engine/6000.7/script-reference/unityengine/lighttransport.md)
* **Assembly:** UnityEditor.CoreModule

```csharp
public static int[] GetShadowmaskChannelsFromLightIndices(InputExtraction.BakeInput bakeInput, int[] lightIndices)
```

### Parameters

**** (\[BakeInput]\(/engine/6000.7/script-reference/unityengine/lighttransport/inputextraction/bakeinput)): The BakeInput containing light configuration data.**** (\[int\[]]\(https\://learn.microsoft.com/dotnet/api/system.int32)): Array of light indices to query for shadowmask channels.

### Returns

| Type                                                           | Description                                                                                                       |
| -------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- |
| [int\[\]](https://learn.microsoft.com/dotnet/api/system.int32) | Array of shadowmask channel indices (0-3 for RGBA, or -1 for no channel) corresponding to each input light index. |

### Remarks

This method maps light indices to their assigned shadowmask channels in Unity's mixed lighting system. Mixed lights use shadowmask textures to store precomputed shadow information while providing real-time lighting.

**Channel Mapping:**

* 0: Red channel.
* 1: Green channel.
* 2: Blue channel.
* 3: Alpha channel.
* -1: Light has no shadowmask channel assigned.

The shadowmask channels are automatically assigned by Unity's lighting system based on light overlap and priority. Use this information to correctly interpret occlusion data from [IProbeIntegrator.IntegrateOcclusion](/engine/6000.7/script-reference/unityengine/lighttransport/iprobeintegrator/integrateocclusion.md).

Additional Resources: ComputeOcclusionLightIndicesFromBakeInput, [IProbeIntegrator.IntegrateOcclusion](/engine/6000.7/script-reference/unityengine/lighttransport/iprobeintegrator/integrateocclusion.md).

### Examples

```csharp
// Get light indices for occlusion computation
var lightIndices = InputExtraction.ComputeOcclusionLightIndicesFromBakeInput(bakeInput, probePositions, 4);

// Map indices to shadowmask channels
var channels = InputExtraction.GetShadowmaskChannelsFromLightIndices(bakeInput, lightIndices);

// Process occlusion results with channel mapping
for (int probeIndex = 0; probeIndex < probeCount; probeIndex++)
{
    for (int lightIndex = 0; lightIndex < 4; lightIndex++)
    {
        int arrayIndex = probeIndex * 4 + lightIndex;
        int globalLightIndex = lightIndices[arrayIndex];
        int shadowmaskChannel = channels[arrayIndex];
        float occlusion = occlusionResults[arrayIndex];

        if (shadowmaskChannel >= 0)
        {
            Debug.Log($"Probe {probeIndex}, Light {globalLightIndex}: " +
                     $"Channel {shadowmaskChannel}, Occlusion {occlusion}");
        }
    }
}
```