# ROS–Unity Initial Setup

The minimum requirements for a ROS–Unity integration.

## ROS Environment

1. Download and copy the [TCP Endpoint](https://github.com/Unity-Technologies/ROS-TCP-Endpoint) package to the `src` folder in your Catkin workspace.

1. Navigate to your Catkin workspace and run `catkin_make && source devel/setup.bash`. Ensure there are no errors.

1. Open a new terminal, navigate to your Catkin workspace, and run:
   
   ```bash
   source devel/setup.bash
   roscore &
   ```

Once ROS Core has started, it will print `started core service [/rosout]` to the terminal window.

1. Note that in the `server_endpoint`, the script fetches parameters for the TCP connection. You will need to know the IP address of your ROS machine as well as the IP address of the machine running Unity. 
   - The ROS machine IP, i.e. `ROS_IP` should be the same value as the one set as `Host Name` on the RosConnect component in Unity.
   - Finding the IP address of your local machine (the one running Unity), i.e. `UNITY_IP` depends on your operating system. 
     - On a Mac, open `System Preferences > Network`. Your IP address should be listed on the active connection.
     - On Windows, click the Wi-Fi icon on the taskbar, and open `Properties`. Your IP address should be listed near the bottom, next to "IPv4 address."

1. The ROS parameter values can be set using a YAML file. Create a `params.yaml` file in your package, e.g. `./config/params.yaml`. Open the file for editing. 

1. Update the `ROS_IP` and `UNITY_IP` below with the appropriate addresses and copy the contents into the `params.yaml` file.

    ```yaml
    ROS_IP: <your ROS IP>
    ROS_TCP_PORT: 10000
    UNITY_IP: <your Unity IP>
    UNITY_SERVER_PORT: 5005
    rosdistro: 'melodic'
    ```
    
    e.g.

    ```yaml
    ROS_IP: 192.168.50.149
    ROS_TCP_PORT: 10000
    UNITY_IP: 192.168.50.13
    UNITY_SERVER_PORT: 5005
    rosdistro: 'melodic'
    ```

    Ensure that the `ROS_TCP_PORT` is set to 10000, and the `UNITY_SERVER_PORT` is set to 5005.

1. Set these newly defined parameters by running `rosparam load`, e.g.:

    ```bash
    rosparam load PATH/TO/config/params.yaml
    ```
    Alternatively, this YAML can be loaded from a launch file, e.g.:

    ```xml
    <launch>
        <rosparam file="$(find <PACKAGE_NAME>)/config/params.yaml" command="load"/>
    </launch>
    ```
	
> Read more about rosparam YAML options [here](http://wiki.ros.org/rosparam).
>
> Read more about the ROS Parameter Server [here](http://wiki.ros.org/Parameter%20Server).

## Unity Scene
1. Launch Unity and create a new scene.
2. Open Package Manager and click the + button at the top left corner. Select "add package from git URL" and enter "https://github.com/Unity-Technologies/ROS-TCP-Connector.git" to install the [ROS TCP Connector](https://github.com/Unity-Technologies/ROS-TCP-Connector) package.

![](images/add_package.png)

![](images/add_package_2.png)

Messages being passed between Unity and ROS need to be serialized exactly as ROS serializes them internally. This is achieved with the RosMessageGeneration utility, which generates C# classes, including serialization and deserialization functions, based on ROS message files. Adding the ROS TCP Connector package should have created a new Unity menu option, “RosMessageGeneration”, which we will use to generate these messages later.