RFR: 8271024: Implement macOS Metal Rendering Pipeline [v3]

[Jayathirth D V]

On Wed, 25 Jun 2025 16:13:46 GMT, Martin Fox <mfox at openjdk.org> wrote:

>> @beldenfox Thanks for pointing to improper isKindOfClass: usage. That is updated now and setOpaque is getting called properly as in mainline.
>> 
>> Regarding reproducing the issue originally seen in PickTest3D : PickTest3D is updated in 2015 under [JDK-8130532](https://bugs.openjdk.org/browse/JDK-8130532) to use alpha value as 1.0 instead of 0.5 for diffuse color. I reverted this change to use 0.5 and disabled calling setOpaque in GlassWindow.m. Unfortunately,  i see proper output with translucent objects and there is no difference in output of PickTest3D with/without setOpaque call even with 0.5 alpha value. As you have also observed in current code setOpaque call has no effect in output even when we use 0.5 alpha value. Currently i am trying get information related to PickTest3D code pre 2015.
>> 
>> Regarding running demos in VM : Is Prism falling back to SW pipeline? (You can check for this info using -Dprism.verbose=true). If it is falling back to SW pipeline in VM, we can try to force it to use hardware pipeline using -Dprism.forceGPU=true.
>
>> Regarding reproducing the issue originally seen in PickTest3D : PickTest3D is updated in 2015 under [JDK-8130532](https://bugs.openjdk.org/browse/JDK-8130532) to use alpha value as 1.0 instead of 0.5 for diffuse color.
> 
> Thanks for tracking that down. The description in [JDK-8130532](https://bugs.openjdk.org/browse/JDK-8130532) references [JDK-8095058](https://bugs.openjdk.org/browse/JDK-8095058). From what I can tell that was the original bug that was causing incorrect results on macOS and covering up the incorrect alpha value in the diffuse color. I think using setOpaque: to rip out the alpha channel was a work-around for JDK-8095058 and is probably no longer necessary.
> 
> But removing the alpha channel made macOS match the output of Windows and Linux. Is JavaFX designed to work without an alpha channel when the window is not TRANSPARENT?
> 
>> Regarding running demos in VM : Is Prism falling back to SW pipeline? (You can check for this info using -Dprism.verbose=true).
> 
> In my Windows VM Prism reports that it's using the D3D pipeline. And Prism isn't throwing any errors or issuing any warnings, it just doesn't draw except for the ColorCube toy.

@beldenfox [JDK-8095004](https://bugs.openjdk.org/browse/JDK-8095004) talks about default opacity of CALayer being NO. But current documentation mentions that by default CALayer is opaque. And there are no pointers whether Apple has changed this behaviour in-between. Also as you mentioned there is update in shader also to ignore alpha channel when its value is 0.0 in [JDK-8095058](https://bugs.openjdk.org/browse/JDK-8095058). So there are lot of factors at different levels which will make PickTest3D to behave differently now compared to pre 2015.

So on current code i have verified that PickTest3D works properly with different combinations of alpha value in diffusecolor and opacity for the stage. Regarding whether we need to remove setOpaque/not : As part for glass refactoring in this PR its better to keep the default ES2 pipeline code as it is.

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PR Comment: https://git.openjdk.org/jfx/pull/1824#issuecomment-3008738532