Why meshs/textures are reverse(flip) in front camera(selfie)?

AeOngDev · May 11, 2021, 2:23am

I really need to know why the mesh is flipped in order to write analysis documents. (Company docs…)
Why, and How Unity work in this parts?
Is there anyone who knows about this?

I am currently using ARCamera and DepthCamera. DepthCamera is necessary in our project. However, since Mesh is upside down in the Scene, it is also seen upside down in Depth Camera.

Now I’ve flipped the Mesh and made it work, but I’m so curious about why it’s flipped in Selfie.

Also, if there’s a better way, I’d like to find it.

The pictures below are before and after execution. (with fish)

<After, The mesh is turned upside down and visceral organs are visible.>

I don’t know if it’s because no one is using AR Camera and Depth Camera at the same time, but I couldn’t find the relevant document.
Please Help…
If there is a related document, I will write a document with it.

Use ARCore Front Camera(user mode). AR Foundation 4.1.1v

KyryloKuzyk · May 21, 2021, 8:14am

It’s the specific of ARCore. When you use Fron Facing camera, you should invert culling on your camera to display everything correctly.
Here is how the official ARCameraBackground script deals with it:

github.com

needle-mirror/com.unity.xr.arfoundation/blob/93bf0079b86b1f5d3162f91ac096669ce0ddeff2/Runtime/AR/ARCameraBackground.cs

using AOT;
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using UnityEngine.Rendering;
using UnityEngine.Serialization;

namespace UnityEngine.XR.ARFoundation
{
    /// <summary>
    /// <para>Add this component to a <c>Camera</c> to copy the color camera's texture onto the background.</para>
    /// <para>If you are using the Lightweight Render Pipeline (version 5.7.2 or later) or the Univerisal Render
    /// Pipeline (version 7.0.0 or later), you must also add the <see cref="ARBackgroundRendererFeature"/> to the list
    /// of render features for the scriptable renderer.</para>
    /// </summary>
    /// <remarks>
    /// <para>
    /// To add the <see cref="ARBackgroundRendererFeature"/> to the list of render features for the scriptable
    /// renderer:
    /// <list type="bullet">

This file has been truncated. show original

line 383: commandBuffer.SetInvertCulling(m_CommandBufferCullingState);

Is there a chance you don’t use the ARCameraBackground in your app?

AeOngDev · May 24, 2021, 4:39am

Thank you for the useful and good information!
Unfortunately, AR Camera’s self-camera function was decided to be excluded at the game.(in meeting not too long ago.)
Although I couldn’t use it this time, I will try inverting curling next time!
It’s so refreshing because you gave me the information I was curious about! Thank you!