RFR: 8322619: Parts of SG no longer update during rendering - overlapping - culling - dirty [v5]

[Florian Kirmaier]

> In some situations, a part of the SG is no longer rendered.
> I created a test program that showcases this problem.
> 
> Explanation:
> 
> This can happen, when a part of the SG, is covered by another Node.
> In this part, one node is totally covered, and the other node is visible.
> 
> When the totally covered Node is changed, then it is marked dirty and it's parent, recursively until an already dirty node is found.
> Due to the Culling, this totally covered Node is not rendered - with the effect that the tree is never marked as Clean.
> 
> In this state, a Node is Dirty but not It's parent. Based on my CodeReview, this is an invalid state which should never happen.
> 
> In this invalid state, when the other Node is changed, which is visible, then the dirty state is no longer propagated upwards - because the recursive "NGNode.markTreeDirty" algorithm encounters a dirty node early.
> 
> This has the effect, that any SG changes in the visible Node are no longer rendered. Sometimes the situation repairs itself.
> 
> Useful parameters for further investigations:
> -Djavafx.pulseLogger=true
> -Dprism.printrendergraph=true
> -Djavafx.pulseLogger.threshold=0
> 
> PR:
> This PR ensures the dirty flag is set to false of the tree when the culling is used.
> It doesn't seem to break any existing tests - but I'm not sure whether this is the right way to fix it.
> It would be great to have some feedback on this solution - maybe guiding me to a better solution.
> 
> I could write a test, that just does the same thing as the test application, but checks every frame that these nodes are not dirty - but maybe there is a better way to test this.

Florian Kirmaier has updated the pull request incrementally with two additional commits since the last revision:

 - JDK-8322619: Add test
 - Revert "JDK-8322619: Clear dirty flag on the node and all its children if they are skipped due to visible==false or opacity==0"
   
   This reverts commit 5f9f1574515c078c1fd0dccd476325090a0b284d.

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1310/files
  - new: https://git.openjdk.org/jfx/pull/1310/files/5f9f1574..e3163f30

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1310&range=04
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1310&range=03-04

  Stats: 204 lines in 2 files changed: 190 ins; 8 del; 6 mod
  Patch: https://git.openjdk.org/jfx/pull/1310.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1310/head:pull/1310

PR: https://git.openjdk.org/jfx/pull/1310