OhosPixelMapCreateOps中的pixelFormat的枚举设置成3和4有一样的效果。

void GPURenderThread::readPixelFromFBO() { 
    std::lock_guard<std::mutex> lk(mutex);
    void *pixels = new GLubyte[imageWidth * imageHeight * 4];
    glReadPixels(0, 0, imageWidth, imageHeight, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
    //使用NativeImage把相机预览流更新到纹理后，从FBO读出来的YUV420SP格式的相机预览帧已经被转成RGBA格式
    //但是buffer如果设置解码成RGBA的PixelMap会偏色
    OpenGlUtils::ConvertRGBAtoBGRA( pixels, imageWidth * imageHeight);
    filterOutputCb->pixelMap.ops.width = imageWidth;
    filterOutputCb->pixelMap.ops.height = imageHeight;
    filterOutputCb->pixelMap.ops.alphaType = 0;
    filterOutputCb->pixelMap.ops.pixelFormat = 3;//pixelFormat设3或4都一样，貌似固定解码成BGRA
    if (filterOutputCb->pixelMap.buffer) {
        delete[] filterOutputCb->pixelMap.buffer;
        filterOutputCb->pixelMap.buffer = nullptr;
    }
    filterOutputCb->pixelMap.buffer = pixels;
    filterOutputCb->OnCallbackAsync();
}

OH_PixelMap_CreatePixelMap(env, pixelMap.ops, (uint8_t *)buff, bufferSize, &result);