# CalculateInterpolatedLightAndOcclusionProbes

> Calculate light probes and occlusion probes at the given world space positions.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine](/engine/6000.0/script-reference/unityengine.md)
* **Assembly:** UnityEngine.CoreModule

## CalculateInterpolatedLightAndOcclusionProbes(Vector3\[], SphericalHarmonicsL2\[], Vector4\[])

Calculate light probes and occlusion probes at the given world space positions.

```csharp
public static void CalculateInterpolatedLightAndOcclusionProbes(Vector3[] positions, SphericalHarmonicsL2[] lightProbes, Vector4[] occlusionProbes)
```

### Parameters

**** (\[Vector3\[]]\(/engine/6000.0/script-reference/unityengine/vector3)): The array of world space positions used to evaluate the probes.**** (\[SphericalHarmonicsL2\[]]\(/engine/6000.0/script-reference/unityengine/rendering/sphericalharmonicsl2)): The array where the resulting light probes are written to.**** (\[Vector4\[]]\(/engine/6000.0/script-reference/unityengine/vector4)): The array where the resulting occlusion probes are written to.

### Remarks

If there are no probes baked in the Scene, the ambient probe will be written to the lightProbes array and Vector4 (1,1,1,1) will be written to the occlusionProbes array.

ArgumentNullException is thrown if positions is null.

You can omit either lightProbes or occlusionProbes array by passing null to the function, but you cannot omit both at the same time. If both arrays are omitted, an ArgumentException is thrown. lightProbes and occlusionProbes should be calculated together for better performance.

For the overload which takes arrays as arguments, the lightProbes and occlusionProbes must have at least the same number of elements as the positions array.

For the overload which takes lists as arguments, the output lists will be resized to fit the size of the positions array if there is not enough space in the given lists.

The returned probes may be further used for instanced rendering by copying them to a MaterialPropertyBlock object via [MaterialPropertyBlock.CopySHCoefficientArraysFrom](/engine/6000.0/script-reference/unityengine/materialpropertyblock/copyshcoefficientarraysfrom.md) and [MaterialPropertyBlock.CopyProbeOcclusionArrayFrom](/engine/6000.0/script-reference/unityengine/materialpropertyblock/copyprobeocclusionarrayfrom.md).

```csharp
using UnityEngine;

// This script uses OnPreCull for the rendering. It is mandatory to put the script to a Camera object.
// Make sure light probes are placed and baked in the Scene.
// Use Shadowmask mode and mixed lights to see occlusion probes approximating shadowness.
[RequireComponent(typeof(Camera))]
public class Simple : MonoBehaviour
{
    public Material material;

    private Matrix4x4[] transforms;
    private MaterialPropertyBlock properties;
    private Mesh cubeMesh;

    void Start()
    {
        const int kCount = 100;

        // Generate 100 random positions
        var positions = new Vector3[kCount];
        for (int i = 0; i < kCount; ++i)
            positions[i] = new Vector3(Random.Range(-20.0f, 20.0f), Random.Range(-20.0f, 20.0f), Random.Range(-20.0f, 20.0f));

        // Calculate probes at these positions
        var lightprobes = new UnityEngine.Rendering.SphericalHarmonicsL2[kCount];
        var occlusionprobes = new Vector4[kCount];
        LightProbes.CalculateInterpolatedLightAndOcclusionProbes(positions, lightprobes, occlusionprobes);

        // Put them into the MPB
        properties = new MaterialPropertyBlock();
        properties.CopySHCoefficientArraysFrom(lightprobes);
        properties.CopyProbeOcclusionArrayFrom(occlusionprobes);

        // Compute the transforms list
        transforms = new Matrix4x4[kCount];
        for (int i = 0; i < kCount; ++i)
            transforms[i] = Matrix4x4.Translate(positions[i]);

        // Create the cube mesh
        cubeMesh = GameObject.CreatePrimitive(PrimitiveType.Cube).GetComponent<MeshFilter>().sharedMesh;

        // Make sure the material property is assigned
        if (material == null || !material.enableInstancing)
            Debug.LogError("material must be assigned with one with instancing enabled.");
    }

    // OnPreCull happens before every culling, which is the perfect timing to inject DrawMesh* function calls.
    void OnPreCull()
    {
        if (material != null && material.enableInstancing)
        {
            RenderParams rp = new RenderParams(material)
            {
                matProps = properties,
                lightProbeUsage = UnityEngine.Rendering.LightProbeUsage.CustomProvided, // enable instancing for probes
                shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.On,
                receiveShadows = true
            };
            Graphics.RenderMeshInstanced(rp, cubeMesh, 0, transforms);
        }
    }
}
```

The example demonstrates how to leverage the baked light probes to enhance the visual quality of instanced rendering.

## CalculateInterpolatedLightAndOcclusionProbes(List\<Vector3>, List\<SphericalHarmonicsL2>, List\<Vector4>)

Calculate light probes and occlusion probes at the given world space positions.

```csharp
public static void CalculateInterpolatedLightAndOcclusionProbes(List<Vector3> positions, List<SphericalHarmonicsL2> lightProbes, List<Vector4> occlusionProbes)
```

### Parameters

**** (\[List\<Vector3>]\(https\://learn.microsoft.com/dotnet/api/system.collections.generic.list-1)): The array of world space positions used to evaluate the probes.**** (\[List\<SphericalHarmonicsL2>]\(https\://learn.microsoft.com/dotnet/api/system.collections.generic.list-1)): The array where the resulting light probes are written to.**** (\[List\<Vector4>]\(https\://learn.microsoft.com/dotnet/api/system.collections.generic.list-1)): The array where the resulting occlusion probes are written to.

### Remarks

If there are no probes baked in the Scene, the ambient probe will be written to the lightProbes array and Vector4 (1,1,1,1) will be written to the occlusionProbes array.

ArgumentNullException is thrown if positions is null.

You can omit either lightProbes or occlusionProbes array by passing null to the function, but you cannot omit both at the same time. If both arrays are omitted, an ArgumentException is thrown. lightProbes and occlusionProbes should be calculated together for better performance.

For the overload which takes arrays as arguments, the lightProbes and occlusionProbes must have at least the same number of elements as the positions array.

For the overload which takes lists as arguments, the output lists will be resized to fit the size of the positions array if there is not enough space in the given lists.

The returned probes may be further used for instanced rendering by copying them to a MaterialPropertyBlock object via [MaterialPropertyBlock.CopySHCoefficientArraysFrom](/engine/6000.0/script-reference/unityengine/materialpropertyblock/copyshcoefficientarraysfrom.md) and [MaterialPropertyBlock.CopyProbeOcclusionArrayFrom](/engine/6000.0/script-reference/unityengine/materialpropertyblock/copyprobeocclusionarrayfrom.md).

```csharp
using UnityEngine;

// This script uses OnPreCull for the rendering. It is mandatory to put the script to a Camera object.
// Make sure light probes are placed and baked in the Scene.
// Use Shadowmask mode and mixed lights to see occlusion probes approximating shadowness.
[RequireComponent(typeof(Camera))]
public class Simple : MonoBehaviour
{
    public Material material;

    private Matrix4x4[] transforms;
    private MaterialPropertyBlock properties;
    private Mesh cubeMesh;

    void Start()
    {
        const int kCount = 100;

        // Generate 100 random positions
        var positions = new Vector3[kCount];
        for (int i = 0; i < kCount; ++i)
            positions[i] = new Vector3(Random.Range(-20.0f, 20.0f), Random.Range(-20.0f, 20.0f), Random.Range(-20.0f, 20.0f));

        // Calculate probes at these positions
        var lightprobes = new UnityEngine.Rendering.SphericalHarmonicsL2[kCount];
        var occlusionprobes = new Vector4[kCount];
        LightProbes.CalculateInterpolatedLightAndOcclusionProbes(positions, lightprobes, occlusionprobes);

        // Put them into the MPB
        properties = new MaterialPropertyBlock();
        properties.CopySHCoefficientArraysFrom(lightprobes);
        properties.CopyProbeOcclusionArrayFrom(occlusionprobes);

        // Compute the transforms list
        transforms = new Matrix4x4[kCount];
        for (int i = 0; i < kCount; ++i)
            transforms[i] = Matrix4x4.Translate(positions[i]);

        // Create the cube mesh
        cubeMesh = GameObject.CreatePrimitive(PrimitiveType.Cube).GetComponent<MeshFilter>().sharedMesh;

        // Make sure the material property is assigned
        if (material == null || !material.enableInstancing)
            Debug.LogError("material must be assigned with one with instancing enabled.");
    }

    // OnPreCull happens before every culling, which is the perfect timing to inject DrawMesh* function calls.
    void OnPreCull()
    {
        if (material != null && material.enableInstancing)
        {
            RenderParams rp = new RenderParams(material)
            {
                matProps = properties,
                lightProbeUsage = UnityEngine.Rendering.LightProbeUsage.CustomProvided, // enable instancing for probes
                shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.On,
                receiveShadows = true
            };
            Graphics.RenderMeshInstanced(rp, cubeMesh, 0, transforms);
        }
    }
}
```

The example demonstrates how to leverage the baked light probes to enhance the visual quality of instanced rendering.