使用EncodeToJPG（在OpenVR中）将Texture2D转换为Byte []

Question

我有一个问题！

我只想...，使用EncodeToJPG（）函数将Texture2D转换为Byte []！

我的工作区是Unity和C＃Script，+ OpenCvSharp。

也许你认为这很容易，但它有一些问题。

这个脚本使用OpenVR（HTC VIVE）。

无论如何，这是我的来源。

var source = SteamVR_TrackedCamera.Source(undistorted);

//Receive texture data from VR.
texture = source.texture;

//Debug.Log(source.texture.width + "/" + source.texture.height);    
//size : 612 /460
if (texture == null)
{
    return;
}

//Input texture data into material, and it's in unity (quad GameObject).
//this G.O print display like camera
material.mainTexture = texture;


//here is my src, I want to save Image but texture.EncodeToJPG has some error.
Cv2.ImShow("_Texture ...", Mat.FromImageData(texture.EncodeToJPG()));
Cv2.ImWrite(SavePath+ "Image.jpg", Mat.FromImageData(texture.EncodeToJPG()));

并且......有问题。变量纹理是Texture2D类型的异常。

if (_texture == null)
{
    _texture = Texture2D.CreateExternalTexture((int)header.nWidth, (int)header.nHeight, TextureFormat.RGBA32, false, false, nativeTex);
    //_texture = new Texture2D(612, 460, TextureFormat.RGBA32, false);

    uint width = 0, height = 0;
    var frameBounds = new VRTextureBounds_t();
    if (trackedCamera.GetVideoStreamTextureSize(deviceIndex, frameType, ref frameBounds, ref width, ref height) == EVRTrackedCameraError.None)
    {
        // Account for textures being upside-down in Unity.
        frameBounds.vMin = 1.0f - frameBounds.vMin;
        frameBounds.vMax = 1.0f - frameBounds.vMax;
        this.frameBounds = frameBounds;
    }
}
else
{
    _texture.UpdateExternalTexture(nativeTex);
    //_texture.Apply();
}

_texture是由函数CreateExternalTexture创建的，它具有名为nativeTex的Intptr类型的参数。

我不知道怎么办？

+++编辑！错误显示+++

Answer 1

由于Unity可能无法直接访问外部纹理，我建议先使用Graphics.Blit（）通过GPU将该纹理传输到RenderTexture。

一旦你在RenderTexture中获得纹理，你需要再跳过一个环，并从RenderTexture.active读取像素到另一个标准的基于RAM的Texture2D，然后你应该能够编码它。

记得在执行ReadPixels（）后应用（）纹理

Answer 2

宣布这个功能：

private Texture2D ReadExternalTexture(Texture externalTexture)
{
    Texture2D myTexture2D = new Texture2D(texture.width, texture.height);
    //myTexture2D => empty Texture2D type variable
    if (myTexture2D == null)
    {
        Debug.Log("var: myTexture2D is null state.");
        myTexture2D = new Texture2D(texture.width, texture.height);
    }

    //Make RenderTexture type variable
    RenderTexture tmp = RenderTexture.GetTemporary(
    externalTexture.width,
    externalTexture.height,
    0,
    RenderTextureFormat.ARGB32,
    RenderTextureReadWrite.sRGB);

    Graphics.Blit(externalTexture, tmp);
    RenderTexture previous = RenderTexture.active;
    RenderTexture.active = tmp;

    myTexture2D.ReadPixels(new UnityEngine.Rect(0, 0, tmp.width, tmp.height), 0,     0);
    myTexture2D.Apply();

    RenderTexture.active = previous;
    RenderTexture.ReleaseTemporary(tmp);

    return myTexture2D;
}

并在void Update（）中使用ReadExternalTexture函数：

_texture = ReadExternalTexture(material.mainTexture);

Mat mat = Mat.FromImageData(_texture.EncodeToPNG());

Cv2.Flip(mat, mat, 0);
//Flip(src, dest, 0->updown flip / 1->leftright flip)

Cv2.Resize(mat, mat, new Size(224, 224));

Cv2.ImShow("Image", mat);
//Cv2.ImWrite(SavePath + "Image.jpg", mat);

这完全奏效了！