Multiple Camera Compositing

Learn how to make a Unity project work with a multi-LeiaCamera setup.

When developing Unity content for Leia displays, it is common practice that developers will want two separate cameras: one to render the 3d scene, and another to render the UI on top of it. This has several benefits, including ensuring the UI is always rendered on top and enabling having different lighting and camera settings for the UI than for the scene camera. The Multiple Camera Compositing sample scene provides an example demonstrating how a multi-camera setup can be implemented using the Leia Unity SDK. The sample scene can be found in Assets/LeiaLoft/Examples/MultipleCameraCompositing.

The hierarchy of the MultipleCameras sample scene has two cameras: the Game Camera, and the UI Camera. Both cameras are rendering 3d objects to the display simultaneously with the UI Camera rendering on top and using alpha blending to show the Game Camera below.

The UI Camera renders the buttons:

While the Game Camera renders the background, asteroids, player space ship, and everything else contained in the game scene:

Setup

The following outlines a method to setup a multi-LeiaCamera configuration in your project for a 3d scene with a 3d UI rendered on top of it

Step 1 - Create Cameras

Create two cameras in your scene, and attach the LeiaCamera component to both. For this example, we will name the first one Game Camera, and a second UI Camera.

Step 2 - Set the Camera's Depths

Set the Game Camera's depth to a lower value, like -1, and the UI Camera's depth to a higher value, like 1, to ensure the UI Camera is rendered on top of the scene camera.