[CanvasItem]-derived nodes that are direct or indirect children of a [CanvasLayer] will be drawn in that layer. The layer is a numeric index that defines the draw order. The default 2D scene renders with index [code]0[/code], so a [CanvasLayer] with index [code]-1[/code] will be drawn below, and a [CanvasLayer] with index [code]1[/code] will be drawn above. This order will hold regardless of the [member CanvasItem.z_index] of the nodes within each layer.
[CanvasLayer]s can be hidden and they can also optionally follow the viewport. This makes them useful for HUDs like health bar overlays (on layers [code]1[/code] and higher) or backgrounds (on layers [code]-1[/code] and lower).
[b]Note:[/b] Embedded [Window]s are placed on layer [code]1024[/code]. [CanvasItem]s on layers [code]1025[/code] and higher appear in front of embedded windows.
[b]Note:[/b] Each [CanvasLayer] is drawn on one specific [Viewport] and cannot be shared between multiple [Viewport]s, see [member custom_viewport]. When using multiple [Viewport]s, for example in a split-screen game, you need create an individual [CanvasLayer] for each [Viewport] you want it to be drawn on.
If enabled, the [CanvasLayer] will use the viewport's transform, so it will move when camera moves instead of being anchored in a fixed position on the screen.
Together with [member follow_viewport_scale] it can be used for a pseudo 3D effect.
Scales the layer when using [member follow_viewport_enabled]. Layers moving into the foreground should have increasing scales, while layers moving into the background should have decreasing scales.
[b]Note:[/b] If multiple CanvasLayers have the same layer index, [CanvasItem] children of one CanvasLayer are drawn behind the [CanvasItem] children of the other CanvasLayer. Which CanvasLayer is drawn in front is non-deterministic.
