How to copy Depth API image to a PNG?

Question

I want to use the Depth API to copy the depth image to a PNG file on Quest 3.

https://developer.oculus.com/documentation/unity/unity-depthapi/#depth-api

I'm modifying the Depth API sample:

https://github.com/oculus-samples/Unity-DepthAPI

I'm getting the RenderTexture from Util.GetEnvironmentDepthTextureId() and XRDisplaySubsystem.GetRenderTexture.RenderTexture. However, when I save the RenderTexture to a PNG image, the image is entirely gray. Each pixel color is CDCDCDCD. The image is 2000x2000.

My problem is very similar to this reddit thread:

https://www.reddit.com/r/oculusdev/comments/17lwzvz/q3_depth_api_accessing_depth_sensor_data_directly/

I looked at the OpenXR Depth API Overview page and I noticed that it says:

"Depth maps should only be accessed between the xrBeginFrame and xrEndFrame calls"

https://developer.oculus.com/documentation/native/android/mobile-depth/#acquiring-depth-maps

The Unity Depth API page says:

"RenderTexture can then be used in rendering or in compute shaders."

Is this why Texture2D.ReadPixels() doesn't work? Because the RenderTexture is only usable between xrBeginFrame and xrEndFrame? How do I copy the RenderTexture to a texture that I can read and then save to a PNG file? I'm not familiar with Unity's rendering or compute shaders.

Rads · Answer

// Each kernel tells which function to compile you can have many kernels#pragma kernel CSMain&nbsp;// Quest3 depth texture reading ( global _EnvironmentDepthTexture)&nbsp;// by Radoslaw Szczygiel.&nbsp;// Nie wstawiac polskich znakow do shadera nawet w komentarzach !!!&nbsp;// Deklaracja tekstury wejsciowej (mapa glebi)Texture2DArray&lt;float&gt; _DepthMap ; //rs dziala bo bez RW, tu tekstura podawana jest&nbsp;//Texture2DArray&lt;float&gt;&nbsp; _EnvironmentDepthTexture; //rs dziala od razu na globalnej teksturze o tej nazwie dostarczanej przez Quest3&nbsp; (Texture2DArray_float tez na Vulcan dziala)&nbsp;// Deklaracja bufora wyjsciowego (do przechowywania punktow)RWStructuredBuffer&lt;float&gt; _PointsBuffer; //rs tu musi byc RW&nbsp;&nbsp;float4 _EnvironmentDepthZBufferParams = float4(-0.2f, -1.0f, 0, 0 ); //x=0.2, y=-1.0//float _MinDistance = 6.0f;//float _MaxDistance = 0.1f;&nbsp;[numthreads(8,8,1)]void CSMain (uint3 id : SV_DispatchThreadID){&nbsp; &nbsp; //float depth = _EnvironmentDepthTexture.Load(int4(id.xy , 0,0)).r; // lub&nbsp; &nbsp; float depth = _DepthMap.Load(int4(id.xy, 0 /*array layer index*/, 0 /* z i ma byc 0 */)).r; // Odczytanie glebokosci piksela z tekstury wejsciowej&nbsp; &nbsp; float inputDepthNdc = depth * 2.0f - 1.0f;&nbsp; &nbsp; float linearDepth = (1.0f / (inputDepthNdc + _EnvironmentDepthZBufferParams.y)) * _EnvironmentDepthZBufferParams.x;&nbsp; &nbsp; //float linearDepth = (1.0f / (inputDepthNdc - 1.0f )) / -5&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;+//* (-0.2f);&nbsp; &nbsp; //float lerpFactor = (linearDepth - _MinDistance) / (_MaxDistance - _MinDistance); //rs dane do kolorowania&nbsp;&nbsp; &nbsp; _PointsBuffer[id.x + (id.y * 2000)] = linearDepth ; //rs 2000 to szerokosc tekstury glebi&nbsp; &nbsp; //rs todo To nie jest raczej odleglosc od kamery tylko skladowa "z" wzgledem plaszczyzny kamery co powoduje mniejsze odczyty im dalej od srodka kamery w dowolnym kierunku&nbsp; &nbsp; //rs np. podnoszac glowe do gury aby dolny punkt objal ten sam punkt sciany do wczesniej srodkowy odczyt jest mniejszy}&nbsp;

Rads · Answer

using Unity.XR.Oculus;using UnityEngine;using UnityEngine.XR;using TMPro;&nbsp;public class ComputeShader1 : MonoBehaviour{&nbsp; &nbsp; public ComputeShader CompShader;//&nbsp; &nbsp; public RenderTexture DepthMap;&nbsp; &nbsp; public int BufferSize = 2000;&nbsp; &nbsp; public TextMeshProUGUI[] myDepthTextArray = new TextMeshProUGUI[9]; //rs add Tu musi być rozmiar jak ilosc el tablicy wektorow "ind" ponizej&nbsp;&nbsp; &nbsp; private ComputeBuffer m_pointsBuffer;&nbsp; &nbsp; private XRDisplaySubsystem m_xrDisplay;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; public float interval = 0.05f; // Interwał czasowy w sekundach&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; // x=1250 i y=1200 to pi * drzwi = srodek. 2000 to szer tekstury głębi 2000x2000 (0..1999) pix#if true&nbsp; //true lub false&nbsp; &nbsp; //prawdziwe miejsca pokrywające się z ekranem&nbsp; &nbsp; const int GORNY_Y = 1550;&nbsp;&nbsp; &nbsp; const int SRODEK_Y = 1100;&nbsp; &nbsp; const int DOLNY_Y = 500;&nbsp; &nbsp; const int LEWY_X = 470; const int SRODEK_X = 1270; const int PRAWY_X = 1999;#else&nbsp;&nbsp; &nbsp; // rozszerzenie aby wykorzystać maksymalnie pole odczytu&nbsp; &nbsp; const int GORNY_Y = 1900;&nbsp; &nbsp; const int SRODEK_Y = 1000;&nbsp; &nbsp; const int DOLNY_Y = 300; //500;&nbsp; &nbsp; const int LEWY_X = 100; const int SRODEK_X = 1300; const int PRAWY_X = 1900;#endif&nbsp; &nbsp; private Vector2Int[] ind = {&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(LEWY_X, GORNY_Y),&nbsp; &nbsp; &nbsp; &nbsp;//0 lewa góra&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(SRODEK_X, GORNY_Y),&nbsp; &nbsp; &nbsp; &nbsp;//1 środkowa góra&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(PRAWY_X, GORNY_Y),&nbsp; &nbsp; &nbsp; &nbsp;//2 prawa góra&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(LEWY_X, SRODEK_Y),&nbsp; &nbsp; &nbsp; &nbsp;//3 lewy środek&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(SRODEK_X, SRODEK_Y),&nbsp; &nbsp; &nbsp; &nbsp;//4 środkowy środek&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(PRAWY_X, SRODEK_Y),&nbsp; &nbsp; &nbsp;//5 prawy środek&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(LEWY_X, DOLNY_Y),&nbsp; &nbsp; &nbsp; &nbsp;//6 lewy dół&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(SRODEK_X, DOLNY_Y),&nbsp; &nbsp; &nbsp; &nbsp;//7 środkowy dół&nbsp; &nbsp; &nbsp; &nbsp; new Vector2Int(PRAWY_X, DOLNY_Y),&nbsp; &nbsp; &nbsp; &nbsp;//8 prawy dół&nbsp; &nbsp; &nbsp; &nbsp; };&nbsp;&nbsp; &nbsp; private void Start()&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; m_xrDisplay = OVRManager.GetCurrentDisplaySubsystem();&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; // Inicjalizacja bufora dla punktów&nbsp; &nbsp; &nbsp; &nbsp; m_pointsBuffer = new ComputeBuffer(BufferSize * BufferSize, sizeof(float) );&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; // Przypisanie bufora do Compute Shadera&nbsp; &nbsp; &nbsp; &nbsp; CompShader.SetBuffer(0, "_PointsBuffer", m_pointsBuffer);&nbsp;&nbsp; &nbsp; }&nbsp;&nbsp; &nbsp; private void Update()&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; uint id = 0;&nbsp; &nbsp; &nbsp; &nbsp; // Używamy modulo, aby sprawdzić, czy przyszedł czas na wykonanie akcji. Próba bedzie podejmowana tylko w jednej klatce (max 2) a następna za kolejny interval&nbsp; &nbsp; &nbsp; &nbsp; // Tak więc opóźnione wywołanie nie wykona się i zostanie ominięte do następnego okienka//&nbsp; &nbsp; &nbsp; &nbsp; if (Time.time % interval &lt; Time.deltaTime) // to nie jest doskonałe&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (Utils.GetEnvironmentDepthTextureId(ref id) &amp;&amp; m_xrDisplay != null &amp;&amp; m_xrDisplay.running)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var rt = m_xrDisplay.GetRenderTexture(id);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (rt != null)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // Uruchomienie Compute Shadera&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var kernelID = CompShader.FindKernel("CSMain");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; CompShader.SetTexture(kernelID, "_DepthMap", rt /*DepthMap*/); //rs mozna tez od razu w shaderze czytac z tej textury bo globalna&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; CompShader.Dispatch(kernelID, BufferSize / 8, BufferSize / 8, 1);&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // Odczytanie danych z bufora&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; float[] points = new float[BufferSize * BufferSize];&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; m_pointsBuffer.GetData(points);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //2000 * 1200 + 1250 // pi * drzwi = srodek. 2000 to szer tekstury głębi. Druga liczba to pion a trzecia to poziom&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; for (int i = 0; i &lt; myDepthTextArray.Length; i++)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; float depth = points[ind[i].y * 2000 + ind[i].x]; // 2000 to szer tekstury głębi. y to pion od dolu a x to poziom od lewej&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; depth = Mathf.Clamp(depth, 0.01f, 8.0f);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myDepthTextArray[i].text = $"{depth,4:0.00}
x={ind[i].x} y={ind[i].y}";&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myDepthTextArray[i].text = $"{depth,4:0.00}
";&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // Przetworzenie otrzymanych punktów (przykładowe działanie)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //foreach (var point in points)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //Debug.Log("Point: " + point);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp;&nbsp; &nbsp; private void OnDestroy()&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; // Zwolnienie bufora&nbsp; &nbsp; &nbsp; &nbsp; if (m_pointsBuffer != null)&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; m_pointsBuffer.Release();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; m_pointsBuffer = null;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }}&nbsp;

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How to copy Depth API image to a PNG?

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