RFR: 8255015: Inconsistent illumination of 3D shape by PointLight

[Kevin Rushforth]

On Wed, 9 Jun 2021 18:22:31 GMT, Andreas Heger <github.com+85555697+andreas-heger at openjdk.org> wrote:

> The inconsistent illumination happens on Macs with retina displays only if the 3D shape is placed in a SubScene. The light sources are located with wrong coordinates in sub scenes and this causes a different illumination. The wrong coordinates for the light sources come from the fact that the retina pixel scale factors are not used in a SubScene.
> 
> With this pull request, the retina pixel scale factors will be also used in SubScenes and this should resolve the bug [https://bugs.openjdk.java.net/browse/JDK-8255015](url)

The fix looks good. I tested it both in isolation and with PR #334 and it works on both a retina and non-retina display.

If you have time to write an automated test, that would be useful, but if not then a manual test would be OK.

modules/javafx.graphics/src/main/java/com/sun/javafx/sg/prism/NGSubScene.java line 211:

> 209:             // The pixel scale factors must be set to the rttGraphics, otherwise the position
> 210:             // of the lights will not be scaled correctly on retina displays
> 211:             // See https://bugs.openjdk.java.net/browse/JDK-8255015

We typically don't put pointers to bug IDs in the code (we used to, and still sometimes do in some special cases, but here it isn't needed).

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PR: https://git.openjdk.java.net/jfx/pull/531