# 多设备同步示例-MultiDeviceSync

功能描述：演示多设备同步操作。

>本示例基于C++ low Level API进行演示

配置程序模式

std::cout << "Please select options: " << std::endl;
std::cout << " 0 --> config devices" << std::endl;
std::cout << " 1 --> start stream" << std::endl;
std::cout << "input: ";
int index = -1;
std::cin >> index;

配置多设备同步

exitValue = configMultiDeviceSync();

区分主从设备

streamDevList.clear();
// Query the list of connected devices
auto devList = context.queryDeviceList();

// Get the number of connected devices
int devCount = devList->deviceCount();
for(int i = 0; i < devCount; i++) {
    streamDevList.push_back(devList->getDevice(i));
}

if(streamDevList.empty()) {
    std::cerr << "Device list is empty. please check device connection state" << std::endl;
    return -1;
}

// traverse the device list and create the device
std::vector<std::shared_ptr<ob::Device>> primary_devices;
std::vector<std::shared_ptr<ob::Device>> secondary_devices;
for(auto dev: streamDevList) {
    auto config = dev->getMultiDeviceSyncConfig();
    if(config.syncMode == OB_MULTI_DEVICE_SYNC_MODE_PRIMARY) {
        primary_devices.push_back(dev);
    }
    else {
        secondary_devices.push_back(dev);
    }
}

开启从设备

std::cout << "Secondary devices start..." << std::endl;
int deviceIndex = 0;  // Sencondary device display first
for(auto itr = secondary_devices.begin(); itr != secondary_devices.end(); itr++) {
    auto depthHolder = createPipelineHolder(*itr, OB_SENSOR_DEPTH, deviceIndex);
    pipelineHolderList.push_back(depthHolder);
    startStream(depthHolder);

    auto colorHolder = createPipelineHolder(*itr, OB_SENSOR_COLOR, deviceIndex);
    pipelineHolderList.push_back(colorHolder);
    startStream(colorHolder);

    deviceIndex++;
}

开启主设备

std::cout << "Primary device start..." << std::endl;
deviceIndex = secondary_devices.size();  // Primary device display after primary devices.
for(auto itr = primary_devices.begin(); itr != primary_devices.end(); itr++) {
    auto depthHolder = createPipelineHolder(*itr, OB_SENSOR_DEPTH, deviceIndex);
    startStream(depthHolder);
    pipelineHolderList.push_back(depthHolder);

    auto colorHolder = createPipelineHolder(*itr, OB_SENSOR_COLOR, deviceIndex);
    startStream(colorHolder);
    pipelineHolderList.push_back(colorHolder);

    deviceIndex++;
}

设置多设备同步间隔时间

// Start the multi-device time synchronization function
context.enableDeviceClockSync(3600000);  // update and sync every hour

进行多设备测试

testMultiDeviceSync();

关闭数据流

// close data stream
for(auto itr = pipelineHolderList.begin(); itr != pipelineHolderList.end(); itr++) {
    stopStream(*itr);
}