Three.js: Glitches in the LensFlare demo

[trusktr]

Description of the problem

In the LensFlare demo, I see glitches that look like this

Three.js version

• [ ] Dev
• [x] r89 (at time of writing)
• [ ] ...

Browser

• [ ] All of them
• [x] Chrome (in Chrome OS, Samsung Chromebook Pro)
• [ ] Firefox (Android version in Chrome OS, unable to reproduce here)
• [ ] Internet Explorer (didn't test)

OS

• [ ] All of them
• [ ] Windows
• [ ] macOS
• [ ] Linux
• [ ] Android
• [ ] iOS
• [x] Chrome OS

Maybe this is just a Chrome OS issue?

[trusktr]

Unable to reproduce in Chrome for macOS. Maybe it's a Chrome OS issue.

[Mugen87]

I unable to reproduce on Chrome (64.0.3282.119) for macOS 10.13.2. Is it the only example where you see such artifacts? Can you please make a test with the dev branch, too?

[Mugen87]

Closing for now. I suggest to open an issue at https://bugs.chromium.org/p/chromium/issues/list

[mrdoob]

Actually, I can reproduce on a PixelBook.

The new version in dev doesn't show the artifacts though:
http://rawgit.com/mrdoob/three.js/dev/examples/webgl_lensflares.html

However, it's also slower. I'll have to investigate...

[mrdoob]

13280 solved the performance issues for me.

[Mugen87]

The performance is still the same on my iMac. But I've noticed that it's highly resolution dependent. If I reduce the size of my window, performance gets much better.

[mrdoob]

Actually... Yeah, I still have performance issues on the MacBook Pro...

Investigating...

[mrdoob]

@Mugen87 After trying everything... Seems like, for whatever reason, adding alpha: true back to the WebGLRenderer fixes the performance issue... 1937e58e8eedff74f2a8c2d3274a56c098cddc38

Do you see the same on your iMac?

[mrdoob]

Note that... This doesn't seem related to the Lensflare code. As I can see the same behaviour by commenting out the light.add( lensflare ); line.

[Mugen87]

Do you see the same on your iMac?

Yes 🎉 . The performance seems to be identical to the previous lensflare implementation. I wonder why alpha: true makes the difference...

[mrdoob]

Yeah... I'll try to reproduce the issue and report the bug. Closing this 🙌

[mrdoob]

Chrome bug for the alpha: false regression:
https://bugs.chromium.org/p/chromium/issues/detail?id=812071

[mrdoob]

Okay, fix landed and should be solved in Chrome 65.

[mrdoob]

I can still reproduce the reported issue though, I'll reopen this to remind myself to report the bug.

[mrdoob]

Okay, Chrome 65 fixed the alpha: true issue. Things are fast once agaIn on MacBook Pros.

I'll report the glitches on Chromebooks next.

[mrdoob]

I was going to say that we shouldn't close because it had not been resolved yet, but I tried on the Pixelbook and I can't reproduce anymore 🎉

[Mugen87]

Understood! 😇