Dual Monitor Application

Dual monitor functionality is intended to enable the creation of dual monitor applications. Using this pipeline, you can have a windowed application on your 2D monitor while rendering a holographic scene on your Looking Glass device. This is achieved by creating an inter-process communicator (IPC) between two Unity applications.

Reviewing the Example Scene

To fully load the example scene:

  1. Open LookingGlass\Examples\7 - Dual Monitor Application

  2. Select the DMA Builder GameObject from the scene hierarchy

  3. In the Dual Monitor Application Manager script, select the Setup\\Open Scenes button

The Setup\\Open Scenes button loads in the _extendedUI scene of the same name. This scene drives the UI on the 2D window. If a scene doesn't exist by this name, this button will create it.

The additional example scene that gets incorporated includes:

It's own DMA Builder game object, with the Dual Monitor Application Manager script field for Display set to Window 2D. This is required so that the scenes can identify which displays they drive.

A canvas to manage the UI. Any Unity content is allowable here.

An IPC (inter-process communicator) that sends events between the two scenes.

Creating your Own Scene

Follow these steps.

  1. Create a New Scene

  2. Remove the default Unity camera and add a Hologram Camera to the scene, found in Assets/LookingGlass/Prefabs/

  3. Add the Dual Monitor Application prefab to your scene

  4. Select the DMA Builder from the scene hierarchy, and click Setup/Open Scene - you'll need to save your scene first

  5. Add a DMA Builder to the second scene

  6. Set the second scene's Dual Monitor Application's Display to Window 2D

  7. Add a DMA IPC object to each scene (if cross-application communication is required

  8. Set the DMA IPC's Dual Monitor Application Base IPC to Looking Glass for the Looking Glass scene, and Window 2D for the 2D scene

  9. Set the Inter Process Communicator's Role to Receiver for the Looking Glass scene and Sender for the 2D scene

  10. Change the Inter Process Communicator's Signing Char to something new that matches in both scenes (recommended)

If the app requires UI elements on the 2D, this can be done using conventional Unity UI elements. There is a prefab provided for you for convenience, DMA Canvas, though you will need to additionally add an Event System to your scene for Unity UI events.

Building a Release

In order to support all Looking Glass Pro functionality, you must build your applications in an unconventional way. Unity's built-in build pipeline will not work. To build the proper way:

Open File > Build Settings... and add both your scenes and click Add Open Scenes to add both scenes to the "Scenes in Build" field

Close the Build Settings window

Select any DMA Builder game object

Click the Build (Dual Monitor Application) button in the Dual Monitor Application Manager script in the inspector

Select an empty folder to bundle your application into

Scripting IPC Functionality

In order to script your own functionality, follow the following steps:

  1. In your script, add a reference to the InterProcessCommunicator in your scene.

  2. To send data (typically from the 2D UI to the Looking Glass display) call InterProcessCommunicator.SendData with a string as the parameter. This will be sent to the receiver. You can call this function either from a script or from UI events.

  3. In the receiving scene (typically the Looking Glass scene), in a script, create a reference to the InterProcessCommunicator in that scene.

  4. Create a function named ReceiveMessage(string message).

  5. This function will now be called when a message is received. Write some logic within this function to handle the various messages the scene will be receiving.

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