The following example project demonstrates the general usage of the plugin by setting up poster-based tracking.
A webcam is mandatory. Connect one if not done already and be aware that a restart of your computer might be required before it is working.
First start Unity. In the launcher window, click on NEW on the upper right, name your project and select the location in your file system. Please remember the latter one, as you will need it later. After assuring that you are about to create a 3D project on the bottom left, click Create project on the bottom right.
Click on Assets in Unity's top menu bar, followed by Import Package and Custom Package.... In the pop-up window, look for a file named vlUnitySDK.unitypackage and open it.
Right click on Main Camera in the Hierarchy panel on the left and select Delete. Then drag and drop the VLCamera prefab from the VisionLib/Utilities/Prefabs/Camera directory into the Hierarchy panel on the left.
Go to your project's directory you chose in the first step (e.g. via macOS Finder or Windows Explorer) and navigate to StreamingAssets/VisionLib/Examples/PosterTracking. Create a new text file and name it TutorialPosterTracker.vl for this example. Make sure your operating system is set to display file endings, so you can correctly rename the whole identifier instead of only the part before the ending. Open your file in a text editor and insert the following content before saving and closing. This is used to describe a poster tracker. Note that you need the referenced image file containing the image on the poster to track (TutorialPoster.png in this example). For more information on the format please refer to the documentation. After that, copy your image to the StreamingAssets/VisionLib/Examples/PosterTracking folder of your project.
{
"type": "VisionLibTrackerConfig",
"version": 1,
"meta": {
"name": "TutorialPosterTracker",
"description": "Tracker for a reference image",
"author": "VisionLib"
},
"tracker": {
"type": "posterTracker",
"version": 1,
"parameters": {
"imageURI": "project_dir:TutorialPoster.png",
"metric":"mm",
"realWidth": 269.0, // Width of the reference image image in mm (default metric is mm)
"transform":{
"t": [0.0, 0.0, 0.0],
//"r": [1.5707963, 0.0, 0.0] // Rotation of 90 deg around x --> ground-plane in XZ
"r": [0.0, 0.0, 0.0]
},
"maxFramesFeaturePrediction": 20,
"extendibleTracking": false,
"debugLevel": 1
}
}
}
Right click on an empty space in the Project panel on the bottom (ideally in the Assets/Scripts directory), select Create and then C# Script. Create a new GameObject with the name VLTrackingStart and assign the script to it.
Open the previously created script. Obtain a reference to VLCamera's VLWorkerBehaviour in C# by inheriting from VLWorkerReferenceBehaviour and calling InitWorkerReference() in the Start function.
Start tracking using the received reference's StartTracking method by passing the name of your tracking configuration file as the only parameter (i.e. StartTracking("Examples/PosterTracking/TutorialPosterTracker.vl");) in the script's Start method's body. Call StopTracking() in OnDestroy's body. Your script should look like the following:
using UnityEngine;
public class Tutorial : VLWorkerReferenceBehaviour
{
private void Start()
{
InitWorkerReference();
workerBehaviour.StartTracking("Examples/PosterTracking/TutorialPosterTracker.vl");;
}
private void OnDestroy()
{
workerBehaviour.StopTracking();
}
}
Return to the Unity window and drag any object into your scene. For example, to place a simple cube right click on an empty space in the hierarchy panel on the left and select 3D Object and then Cube. Adjust the object's scaling so it's not too small. The scene will be rendered where the tracked real-world object is located in the stream, so it is wise to place your objects close to and above the origin (0|0|0) of the coordinate system in order to be able to see your scene.
Run your project by clicking on the play button which you can find above the scene panel in the center. Print the poster and put it on the table or display it on a monitor. Point the camera on it. As soon as VisionLib has detected the poster you should see the cube augmented on it in Unity. Try different positions and angles if VisionLib doesn't recognize the poster immediately.
