The drawable to use for the current frame.
- iOS 9.0+
- macOS 10.11+
- Mac Catalyst 13.0+
- tvOS 9.0+
If all drawable objects are in use, the value of this property is
nil. Your app should check that
nil before attempting to draw. The view changes the value of this property only after returning from a drawing function, either
draw(_:) from a subclassed instance of the view, or
draw(in:) from the view’s delegate.
MTLRender object to render into the drawable’s texture and present it for display (typically registered using the
present(_:) method of a command buffer). Try to minimize the time between when you fetch the drawable and when you submit the command buffer that uses it. For more information, see Keeping References to Drawables.