Day: August 31, 2024

The following notes were taken from my audio recording + the video recording by Pantera (embedded at the end of this summary) of the Third-Party Developer meeting (TPVD) held on Friday, August 30th, 2024. My thanks to Pantera as always for providing it.

Meetings Purpose

• The TPV Developer meeting provides an opportunity for discussion about the development of, and features for, the Second Life viewer, and for Linden Lab viewer developers and third-party viewer (TPV) / open-source code contributors to discuss general viewer development. This meeting is held once a month on a Friday, at 13:00 SLT at the Hippotropolis Theatre.
• Dates and times are recorded in the SL Public Calendar, and they re conducted in a mix of Voice and text chat.
• The notes herein are a summary of topics discussed and are not intended to be a full transcript of the meeting.

Official Viewers Status

[Video: 1:25-4:45]

• Release viewer: version 7.1.9.10515727195, formerly the Atlasaurus RC (object take options; improved MOAP URL handling) promoted August 26.
• Release channel cohorts:
  • DeltaFPS RC, version 7.1.10.10622905308, issued August 30th.
    • Performance boosts. Memory management has been optimized and users will experience a higher FPS across various systems. A comprehensive range of bug fixes are also provided. This includes better PBR material handling and resolving frequent crashes. See the release notes for more.
    • UI for scheduling region restarts now available via a new button located in the Region/Estate floater. (Note: there is currently an issue with scheduled region restarts working correctly and a fix is due to come in the next server release).
• The next viewer to surface after DeltaFPS will have further bug fixes and improvements.

Graphics / PBR

Performance Issues Update

On Thursday, August 29th, Linden Lab issued the following via the Grid Status report mechanism:

We have seen an increase in crashes for some Residents on Windows with older Intel HD-based graphics (GPUs) after the latest release of Second Life Viewer 7.1.9.

If you are experiencing such issues, be sure to download and try the DeltaFPS RC given above. This has a lot of changes and fixes to things like bugs, and to texture loading, memory management (including running the viewer in the background), etc, and those testing it who encounter issues are asked to file reports.

Work Status

[Video: 4:58-7:00]

From Runitai Linden:

We’ve been going over statistics trying to figure out what went wrong and in our stats, 7.1.6 [quoted as 7.1.7] was running quite well, and 7.1.8 [the Graphics Features viewer release] was running quite badly. Atlasaurus [the current release at the time of writing – 7.1.9.10515727195] gets us back up close to where were with 7.1.6, but not quite to where we want to be, so we’ll see where DeltaFPS lands and will get some statistics on that over the weekend. 

We do know some low-end systems are having problems with the PBR update, so we’re still looking at that. for example, we’ve noticed that on Nvidia GT1030s [[GPU released in 2017] we’re had a large drop-off of users from users on those cards. Now we have some of those in-house, and we’ll be making sure … they run well on those. 

Most of the issues for low-ends seem to be coming from running out or memory, and there was a bug that went out  with Featurettes that caused the viewer to think that you had system memory available, and it would continue to allocate textures and then run out of memory and your performance would go to crap and you’d crash. So that’s been fixed in Delta FPS, it was not fixed in Atlasaurus, so were hoping to see the trend continue to improve with the release of DeltaFPS. 

– Runitai Linden, video: 4:58-6:47

• Runitai further indicated that DeltaFPS is running SL a lot better than has been the case for some time, and that the graphics team are continuing to work on things.
• [Video 35:49-38:17] Whilst PBR  / mirrors have been blamed for the performance impacts people are experiencing, outside of issues with the likes of GT1030 GPUs mentioned above, LL’s investigations have show that the performance issues evident in the Graphics Featurettes viewer are not related directly to PBR or mirror rendering (although the latter will naturally impact FPS – just not to the degree people have witnessed).
  • Rather, the issues are related to bugs with elements such and bounding box management and memory management which had been previously missed, but particularly came to the fore with Firestorm’s PBR release.
  • Retrospectively, Runitai acknowledges that LL should have picked up on the issues before the Graphics Featurettes code was released, as they had all the data to hand. As a result, the release process has been adjusted to try to account for these circumstances to try to prevent a similar occurrence in the future.
• [Video: 16:59 in text] Everything Looks Black and White should be fixed in either the current Altasaurus release viewer or in the DeltaFPS RC.

Improved Controls for Visual Aesthetics

[Video: 7:39-13:30]

This is currently work in progress and includes:

• Linear alpha blending: in order for PBR lighting to render anywhere close to correctly, alpha blending has to be switched from SRGB to linear colour space. This can cause some older content using Blinn-Phong, causing it to look either more opaque or more transparent than in did pre-PBR.
  • The fix for this will likely be to add the ability for people to set and alpha/gamma ramp on an item, which can be modified per texture entry, adjusting how transparent the item is on a curve.
    • This should help with a range of issues – particularly those associated with pre-PBR hair, as has been noted by an number of users.
    • To help with this, the new alpha/gamma ramp value will still be adjustable even if the content is No Mod, so as to allow users to adjust legacy content affected by the issue, rather than having to wait for  fixes from content creators.
  • This fix will hopefully follow in the viewer after DeltaFPS.
• Tone mapping is another aesthetic being looked at.
  • Rye Cogtail from the Alchemy team has contributed a neutral tone mapper which is not as dark as the current default in the viewer, and LL are looking to make these the default for tone mapping (subject to the outcome of testing).
  • In addition, LL are looking to re-add tone mapping controls to the Advanced Graphics floater.
  • These were available as debugs early in the PBR beta, but creators found it confusing as to which tone mapper they should target.  However, it is hoped that creators now understand that tone mapping is something that should be done by the renderer and not something dome to the diffuse map in PhotoShop (or equivalents).
• Auto-exposure: LL is looking to add controls for dynamic exposure (speed of transition, range, ability to turn off / on). These options will be made available via the Advanced Graphics floater, and maybe / someday via the the sky settings floaters.
• The overall hope is that by adding additional functionality and options like this, LL will be in a better position to identify defaults that don’t cause users angst by making things look too different all at once, and will provide users with all the tools they need to adjust their visuals to their liking when changes are made.

WebRTC

[Video 15:00-15:36]

Summary

• A new project intended to move Second Life away from reliance on the Vivox voice service and plug-in, and to using the WebRTC communications protocol (RTC=”real-time communication”). Roxie Linden is leading this work.
• Key benefits:
  • WebRTC supports a wide range of real-time communications tools in common use (e.g. Google Meet), supporting audio, video and data communications, and is thus something of a “standard” approach.
  • Offers a good range of features: automatic echo cancellation, better noise cancellation and automatic gain control, much improved audio sampling rates for improved audio quality.
  • Opens the door to features and capabilities to voice services which could not be implemented whilst using Vivox.

Status

• Once the viewer-side updates for WebRTC is widely adopted, the switch for the back-end switch over from Vivox to WebRTC will be thrown.
  • The hope is that this could happen in September, depending on how fast TPVs adopt and release the viewer code.
  • [Video 17:39-18:12] In order to minimise the impact of running both Vivox and WebRTC side-by side, it is hoped that switching to WebRTC can be completed in two step: throwing the switch for all simulators on the RC channels one week,  and a week later switching all simulators on the SLS Main channel.
• In the meantime, peer-to-peer and ad-hoc WebRTC can be tested on the WebRTC regions of WebRTC Voice 1, WebRTC Voice 2, WebRTC Voice 3 and WebRTC Voice 4. However, there is no bridging between WebRTC peer-to-peer  / ad-hoc and Vivox.

In Brief

Please refer to the video, below.

• [Video: 19:16-21:52] Will PBR will replace the “old clothing system” one day?
  • Short answer: on a technical level, probably not, given the longevity of content of all kinds in SL. However, whether creators continue use older system / methodologies are newer ones emerge is  down to choice / what drives their market.
  • That said, PBR will impact system layer clothing in as much as LL are actively working on 2K Bakes on Mesh, after which they will be looking at adding PBR to system layers.
  • In respect of legacy content / capabilities, this is why things like Blinn-Phong materials continue to be supported, etc.
• [Video: 22:32-26:10] Exclusion volumes / invisiprim replacements:
  • There have been a number of requests for exclusion volumes to keep water out of boat hulls and particle weather like rain and dusty wind outside of buildings. etc. These are seen as being something for the longer-term roadmap.
  • In terms of providing an invisiprim style capability outside of this type of use, specific Canny feature requests on why and how such a capability (or options) are required / would be used were requested.
• [Video: 28:06-32:08] SSR causes moiré-like patterns on the water (formerly BUG-233647): this has been a particular issue for those who enjoy pursuits like sailing and boating, or who simply like to look out over Linden Water.
  • The issue is rooted in the implementation of reflection probes, which required a simplification of the water shader so it did not dominate frame rendering.
  • Screen Space Reflections (SSR) was an attempt to redress this and get SL back to high-quality water rendering, but has not worked as hoped.
  • Geenz Linden is now looking to use some of the work on planar mirrors to possibly allow high-quality water reflections once more. However, this will impact viewer FPS when enabled, and if implemented.
  • It was also noted that there were performance issues with the release of mirrors and hero probes in the Graphics Featurettes viewer, but some of these have been fixed & mirrors are now defaulted to “off”, no matter what the graphics quality default is.
• [Video 31:41-35:48] The above led to a broader discussion as to the perception of what PBR is for, how the changes were communicated, the need for creators to fully understand the differences in how they might have used PBR (e.g. baking reflections into the diffuse map) when producing textures and materials prior to the introduction of PBR support, and how they should be doing things now when using PBR, etc.
• [Video: 42:00-46:16] a discussion on a  texture loading issue, potentially fixed using the the multithreaded texture debug option, on Mac systems running Apple Silicon. This appears to be a test on a bug fix that had been implemented to try to eliminate issues of texture loading on Silcon, and might offer an alternative solution, but needs investigation.
• Firestorm Notes:
  • [Video: 46:26-51:50] 2K textures in Group Profiles: it has been noted that the use of 2K textures for Group Profile images will crash Firestorm 6.6.17 (pre-PBR release) for any user using that viewer who opens the Group Profile or tries to join the Group. So the request is (for now) for people not to use 2K textures as Profile images.
  • It was noted that Firestorm’s 3-version viewer policy stems from an old LL policy (introduced under Oz Linden’s tenure as VP of Engineering) which LL no longer adhere to (and by extension, TPVs are not obliged to adhere to if they do not wish to).

Next Meeting

• Friday, September 27th, 2024 at the Hippotropolis Theatre.

† The header images included in these summaries are not intended to represent anything discussed at the meetings; they are simply here to avoid a repeated image of a gathering of people every week. They are taken from my list of region visits, with a link to the post for those interested.