Passthrough Color LUT Tutorial

• Create a new scene containing just the Directional Light and OVRCameraRig.
• Create a short script that will set the OVRPassthroughLayer color LUT property using an existing Texture2D asset. This script uses the OVRPassthroughColorLut class to impose the color changes.
• Set up the scene and assemble the parts.

• Review the information about Color Mapping Techniques
• You should first do the Passthrough Basic Tutorial. Once you complete that, you will be ready to do the Passthrough Color LUT tutorial.

1. In the Project tab, under the Assets folder, create a new folder named Passthrough Color LUT Tutorial, and then select it to make it the current folder for new objects.
2. In the Project Hierarchy, right click SampleScene, and choose Save Scene As. Give the new scene a unique name, such as PassthroughColorLUTTutorial. This becomes the active scene in the Hierarchy.
3. Remove any game objects from the scene, except for the Directional Light and OVRCameraRig.

1. On the top menu, go to Assets > Create > C# Script, and name it PassthroughColorLUTController.
2. Double-click the new script to open it.
3. Create a serialized Texture2D field by adding the following code snippet to the PassthroughColorLUTController class. Later, we will assign our Texture2D asset to it in the Inspector.

   [SerializeField]
   private Texture2D _2dColorLUT;
   public Texture2D ColorLUT2D => _2dColorLUT;
   
4. In the Start script, we want to instantiate the OVRCameraRig, the OVRPassthroughLayer, and the Texture2D object.

   private OVRPassthroughColorLut ovrpcl;
   private OVRPassthroughLayer passthroughLayer;
   
   void Start()
   {
       OVRCameraRig ovrCameraRig = FindObjectOfType<OVRCameraRig>();
       if (ovrCameraRig == null)
       {
           Debug.LogError("Scene does not contain an OVRCameraRig");
           return;
       }
   
       passthroughLayer = ovrCameraRig.GetComponent<OVRPassthroughLayer>();
       if (passthroughLayer == null)
       {
           Debug.LogError("OVRCameraRig does not contain an OVRPassthroughLayer component");
           return;
       }
   
       ovrpcl = new OVRPassthroughColorLut(_2dColorLUT, flipY: false);
       passthroughLayer.SetColorLut(ovrpcl, weight: 1);
   }
   
   For this tutorial, the relevant action is setting the passed-in LUT image into the passthrough layer. When we create the color LUT object, we specify the passed-in LUT image, and a value of false for flipY (the image we will use is already flipped -- that is, the solid black portion of the image is to the lower right).
   When we call SetColorLut, we provide the passed-in LUT image, and a weight value of 1, since we want the colors to be taken fully from the LUT.
5. Save the script.

1. In the Hierarchy window, click OVRCameraRig.
2. In the Inspector, scroll to the bottom and choose Add Component.
3. Search for the PassthroughColorLUTController and add it.

1. In the Inspector, expand the Passthrough Color LUT Controller component.
2. Save the following inverted-lut image to your Assets folder. This image comes from the Starter Samples project. Make sure the Compression value of the asset is set to None.
3. Drag the inverted-lut asset to the Passthrough Color LUT Controller component 2d Color LUT field.

1. In the Hierarchy window, click OVRCameraRig.
2. In the Inspector, expand the OVR Passthrough Layer component.
3. In the Color Control dropdown, choose Color LUT.
4. Drag the inverted-lut asset to the OVR Passthrough Layer component LUT field. If prompted, select Fix image compression.

1. On the top menu, go to File > Save, and then go to File > Save Project.
2. On the top menu, go to File > Build Settings to open the settings window.
3. Remove the previous scenes from the Scenes in Build pane. Then click Add Open Scenes. Only your new PassthroughColorLUTTutorial should be in the build.
4. Make sure that the Run Device is set to Meta Quest headset that is connected via USB cable.
5. Click Build and Run.
6. Save the .APK file.
7. Put on the headset to test the color effect. Your passthrough environment should resemble the following figure:
   

using UnityEngine;

public class PassthroughColorLUTController : MonoBehaviour
{
    [SerializeField]
    private Texture2D _2dColorLUT;
    public Texture2D ColorLUT2D => _2dColorLUT;
    private OVRPassthroughColorLut ovrpcl;
    private OVRPassthroughLayer passthroughLayer;

    void Start()
    {
        OVRCameraRig ovrCameraRig = FindObjectOfType<OVRCameraRig>();
        if (ovrCameraRig == null)
        {
            Debug.LogError("Scene does not contain an OVRCameraRig");
            return;
        }

        passthroughLayer = ovrCameraRig.GetComponent<OVRPassthroughLayer>();
        if (passthroughLayer == null)
        {
            Debug.LogError("OVRCameraRig does not contain an OVRPassthroughLayer component");
            return;
        }

        ovrpcl = new OVRPassthroughColorLut(_2dColorLUT, flipY: false);
        passthroughLayer.SetColorLut(ovrpcl, weight: 1);
    }

    void Update()
    {
    }
}