JDK-8222258: Add exclusion scope for LightBase

[Kevin Rushforth]

Hi Nir,

This seems like it would be a useful addition to the JavaFX 3D lighting 
API. You highlighted the two things that need to be clearly defined in 
terms of semantics:

1. Parent node in the inclusion list, descendant node in the exclusion 
list (or vice versa)
2. A node in both lists

I think your main idea about the rules for the first question seems 
exactly right: a node that is in one list or the other overrides any 
ancestor node and that will applies to all descendants which are not in 
one of the lists of scopes. If the inclusion list is empty, it behaves 
exactly the same as if the root node were the only node in the inclusion 
list.

For the second question, you outlined three possibilities. My initial 
thought is that the complexity of moving it from one list to another 
(which is what happens with child nodes of a parent) is not worth the 
effort. I would recommend that one or the other take precedence 
(probably the exclusion).

-- Kevin


On 4/18/2019 9:54 PM, Nir Lisker wrote:
> Hi Kevin/Johan,
>
> I submitted an enhancement request to add an "exclusion scope" to LightBase
> [1]. The "exclusion scope" is a list of nodes which should not be affected
> by the light. It's a convenient alternative for adding all of the nodes to
> the scope except for the ones which should be excluded.
>
> I've written a preliminary Webrev and a sample app that demonstrates the
> behavior.
>
> Please evaluate,
> Nir
>
> [1] https://bugs.openjdk.java.net/browse/JDK-8222258