Layer system

[vorg]

Often we need to render different parts of scene to different cameras with potentially different viewports.

Proposed implementation adds layer property to an entity. With the following rules:

• if camera has no layer assigned it renders only entities with no layer assigned
• if camera has layer assigned it renders entities with no layer assigned or with a matching layer

Consider following setup

floorEntity
directionalLightEntity
redCubeEntity.layer = 'debugView'
debugCameraEntity.layer = 'debugView'
blueCubeEntity.layer = 'mainScene'
cameraEntity.layer = 'mainScene'

You would then draw two cameras at once

renderEngine.render(
    world.entities,
    cameraEntities)

Render engine would go through all cameras and:

• cameraEntity would render floor + directionalLight + blueCubeEntity
• debugCameraEntity would render floor + directionalLight + redClubeEntity

By default both cameras would be drawn on top of each other unless they have viewport specified

debugCameraEntity.viewport = [10, 10, 200, 200]