[Rev 03] RFR: 8217472: Add attenuation for PointLight

[Michael Paus]

Am 25.04.20 um 19:09 schrieb Kevin Rushforth:
> On Fri, 24 Apr 2020 05:06:56 GMT, Phil Race <prr at openjdk.org> wrote:
>
>>> Here is a slightly modified test program. It fixes a compilation error in the previous, and also adds a system property
>>> to set the number of quads:
>>> It creates 200 quads by default. If you need to increase this or decrease it to get something in the ~ 10 fps range you
>>> can do that with `-DnumQuads=NNNN`.
>>> [pointlighttest.zip](https://github.com/openjdk/jfx/files/4526179/pointlighttest.zip)
>> @kevinrushforth
>> Member
>> kevinrushforth commented Apr 18, 2020
>>
>> I think most of those are good suggestions going forward. As for the performance drop, the only place we've seen it so
>> far is on graphics accelerators that are a few years old by now.
>> So 50% drop on a 2015 macbook pro is OK ? Do we have numbers on recent macbook pros ?
> If this were an even remotely representative use case, then no, the performance hit would not be OK. The test was
> designed as an artificial "worst-case" stress test: a single mesh with a large number of very large (window-sized)
> quads stacked on top of each other. Any real-world use case won't do this.
>
> We should make sure that we aren't seeing any significant performance drop when rendering spheres (at a couple
> different tessellation levels) or boxes.
>
> -------------
>
> PR: https://git.openjdk.java.net/jfx/pull/43

Will there also be any performance drop in case you just use the default 
parameters for the lighting?
The default, which corresponds to the current lighting, should not need 
any additional computations
and thus no performance drop.