# IntegrateDirectRadiance(IDeviceContext, int, int, int, bool, BufferSlice<SphericalHarmonicsL2>)

> Computes direct lighting contribution at probe positions using spherical sampling.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine.LightTransport](/engine/6000.6/script-reference/unityengine/lighttransport.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
IProbeIntegrator.Result IntegrateDirectRadiance(IDeviceContext context, int positionOffset, int positionCount, int sampleCount, bool ignoreEnvironment, BufferSlice<SphericalHarmonicsL2> radianceEstimateOut)
```

### Parameters

**** (\[IDeviceContext]\(/engine/6000.6/script-reference/unityengine/lighttransport/idevicecontext)): Device context for computation and memory operations.**** (\[int]\(https\://learn.microsoft.com/dotnet/api/system.int32)): Starting index in the probe position buffer.**** (\[int]\(https\://learn.microsoft.com/dotnet/api/system.int32)): Number of probe positions to process.**** (\[int]\(https\://learn.microsoft.com/dotnet/api/system.int32)): Number of samples to take per probe.**** (\[bool]\(https\://learn.microsoft.com/dotnet/api/system.boolean)): If true, excludes environment lighting from the direct contribution calculation.**** (\[BufferSlice\<SphericalHarmonicsL2>]\(/engine/6000.6/script-reference/unityengine/lighttransport/bufferslice1)): Output [BufferSlice](/engine/6000.6/script-reference/unityengine/lighttransport/bufferslice1.md) that the direct radiance estimate is written into, encoded as [SphericalHarmonicsL2](/engine/6000.6/script-reference/unityengine/rendering/sphericalharmonicsl2.md).

### Returns

| Type                                                                                            | Description                                                           |
| ----------------------------------------------------------------------------------------------- | --------------------------------------------------------------------- |
| [Result](/engine/6000.6/script-reference/unityengine/lighttransport/iprobeintegrator/result.md) | Result indicating success or failure with detailed error information. |

### Remarks

This method performs spherical sampling around each probe position to compute direct lighting contributions from all light sources in the scene. The results are stored as [SphericalHarmonicsL2](/engine/6000.6/script-reference/unityengine/rendering/sphericalharmonicsl2.md) that can be used for real-time lighting lookups.

Direct radiance includes contributions from:

* Directional lights
* Point lights
* Spot lights
* Area lights
* Environment lighting (unless ignored)

The quality of the integration depends on the sample count - higher values produce more accurate results but require more computation time.

### Examples

```csharp
// Extract scene data
bool result = InputExtraction.ExtractFromScene(out var input);
Assert.IsTrue(result);

// Create context and world
using var context = new RadeonRaysContext();
Assert.IsTrue(context.Initialize());
var world = new RadeonRaysWorld();

// Populate world with scene data
using var progress = new BakeProgressState();
var worldResult = InputExtraction.PopulateWorld(input, progress, context, world);
Assert.IsTrue(worldResult);

// Create integrator
var integrator = new RadeonRaysProbeIntegrator();
integrator.SetProgressReporter(progress);

// Prepare probe positions
var probePositions = new NativeArray<Vector3>(64, Allocator.Persistent);
// ... fill probe positions ...

BufferID posBuffer = context.CreateBuffer(64, 12); // Vector3 = 12 bytes
var posSlice = new BufferSlice<Vector3>(posBuffer, 0);
context.WriteBuffer(posSlice, probePositions);

// Prepare integrator.
integrator.Prepare(context, world, posSlice, 0.1f, 2);

// Integrate direct lighting
var result = integrator.IntegrateDirectRadiance(
    context,
    0,        // Start from first probe
    32,       // Process 32 probes
    64,       // Faster, low quality sampling, usually okay for final bake if area lights are not used.
    false,    // Include environment lighting
    shBuffer
);

if (result.type != IProbeIntegrator.ResultType.Success)
{
    Debug.LogError($"Direct radiance integration failed: {result}");
}
// Cleanup
integrator.Dispose();
context.DestroyBuffer(posBuffer);
context.DestroyBuffer(shBuffer);
probePositions.Dispose();
```