RFR: 8217472: Add attenuation for PointLight

[Nir Lisker]

On Fri, 20 Dec 2019 21:56:32 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> The bug I mentioned above is not a bug actually. There are large changes over a small distance that make it looks like a jump in the lighting values, but when working with a finer scale the lighting dynamics seem correct.
> 
> I think this is on the right track. The API looks like it is in good shape.
> 
> This will need a fair bit of testing to ensure that there are no regressions either in functionality or (especially) performance, in addition to tests for the new functionality. On the performance aspect, the inner loop of the lighting calculation now has an additional if test for the max range and additional arithmetic calculations for the attenuation. What we will need is a test program that we can run on Mac and Windows to measure the performance of rendering in a fill-rate-limited case. Ideally, we would not pay much of a performance hit in the default case where `ca == 1, la == 0, qa == 0`, but we first need to be able to measure the drop in performance before we can say whether it is acceptable.
> 
> Speaking of testing, I took the current patch for a test drive on Mac and Windows. I get the following system test failures on Mac, and also the same failure using fx83dfeatures/LightMotion in toys.
> 
> 
> Shader compile log: ERROR: 0:308: Use of undeclared identifier 'range'
> ERROR: 0:316: Regular non-array variable 'dist' may not be redeclared
> 
> test.robot.test3d.MeshCompareTest > testSnapshot3D[3] STANDARD_ERROR
>     java.lang.RuntimeException: Error creating fragment shader
>     	at javafx.graphics/com.sun.prism.es2.ES2Shader.createFromSource(ES2Shader.java:141)
>     	at javafx.graphics/com.sun.prism.es2.ES2PhongShader.getShader(ES2PhongShader.java:177)
>         ...
> test.robot.test3d.MeshCompareTest > testSnapshot3D[3] FAILED
>     java.lang.IllegalArgumentException: Unrecognized image loader: null
>         at javafx.graphics/javafx.scene.image.WritableImage.loadTkImage(WritableImage.java:278)
>         at javafx.graphics/javafx.scene.image.WritableImage$1.loadTkImage(WritableImage.java:53)
>         at javafx.graphics/javafx.scene.Scene.doSnapshot(Scene.java:1340)
>         at javafx.graphics/javafx.scene.Scene.doSnapshot(Scene.java:1372)
>         at javafx.graphics/javafx.scene.Scene.snapshot(Scene.java:1462)
>         at test.robot.test3d.MeshCompareTest.lambda$testSnapshot3D$0(MeshCompareTest.java:315)
> 
> 
> test.robot.test3d.Snapshot3DTest > testSnapshot3D[3] FAILED
> (same failure as above)
> 
> 
> test.robot.test3d.Snapshot3DTest > testSnapshot3D[7] FAILED
> (same failure as above)

> I get the following system test failures on Mac
> ```
> Shader compile log: ERROR: 0:308: Use of undeclared identifier 'range'
> ERROR: 0:316: Regular non-array variable 'dist' may not be redeclared
> ```

I don't have a Mac to test on, but on Ubuntu system tests pass (I ran the `test` command for systemTests). Does the sample app I attached also fail on Mac? They both use the same shaders, so I wonder where the issue could be.
Moreover, the error messages are strange. `dist` is not redeclared and `range` is not undeclared in the shader. The error message seems to originate from the native function `Java_com_sun_prism_es2_GLContext_nCompileShader` in `GLContext.c`, not managing to compile the shader, but I can't tell why.

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

PR: https://git.openjdk.java.net/jfx/pull/43