Mesh/Archive/2012-04-23

==Agenda==
# For a simple mesh, triangles in the same mesh and with the same material, when textured with a transparent texture, appear to be rendered in the order the triangles appear in the collada file. This can be used to vercome the alpha-sorting-glitch. Would it be correct to assume this is because the triangles are submitted to opengl in that order? If so, is the rendering code guaranteed to always submit triangles to opengl in the order they appear in the collada file, in particular for more complex meshes? Drongle McMahon
# {repeat from last week 'cos I missed it and there's no transcipt} Any progress on fixing SVC-7727? Drongle McMahon
==Meeting Notes==
* [12:01] Second Life: Teleport completed from LindenWorld B (141,86,47)
* [12:03] Aargle Zymurgy: hey Prep.
* [12:03] Prep Linden: yoyo
* [12:03] Vir Linden: Howdy folks.
* [12:03] Racush (racush.cheeky): hi
* [12:03] Vir Linden: Nyx is out this week, so we can get started any time.
* [12:04] Keli Kyrie: Hello Vir
* [12:04] Vir Linden: First question: For a simple mesh, triangles in the same mesh and with the same material, when textured with a transparent texture, appear to be rendered in the order the triangles appear in the collada file. This can be used to vercome the alpha-sorting-glitch. Would it be correct to assume this is because the triangles are submitted to opengl in that order? If so, is the rendering code guaranteed to always submit triangles to opengl in the order they appear in the collada file, in particular for more complex meshes? Drongle McMahon
* [12:06] Vir Linden: so how would you overcome the alpha sorting glitch? It seems like the correct ordering is view-dependent.
* [12:07] Drongle McMahon: Not for a single material - it's dependent on the triangle order in the Collada ... at least for the experiments I did ...
* [12:08] Drongle McMahon: http://community.secondlife.com/t5/Mesh/Transparent-textures-on-rigged-mesh-bug-out/m-p/1494229/message-uid/1494229#U1494229
* [12:08] Drongle McMahon: I remember that from way back in the beta too.
* [12:09] Drongle McMahon: It can be very useful with trees etc.
* [12:09] Vir Linden: I think we have a general issue with sorting transparency within our rendering system.
* [12:09] Vir Linden: Is this something specific to mesh, or just another aspect of that?
* [12:10] Gramma Fiddlesticks: I'd say that's an issue related to pretty much anything at all that uses transparencies.
* [12:10] Drongle McMahon: Just mesh ... you can't change the order of (mesh) faces for other prims.
* [12:10] Koli Melune (sahkolihaa.contepomi): Vir, sorting transparency is a rendering problem in general.
* [12:11] Koli Melune (sahkolihaa.contepomi): This is why games use alpha masks where possible.
* [12:11] Drongle McMahon: I don't think it's an issue, it's a feature. I just wondered if anyone knew whether it always worked.
* [12:12] Vir Linden: certainly it would not be guaranteed with any automatic LODs
* [12:12] Nal (nalates.urriah): ...and do TPV's use a different sort code? I would expect them to all use LL's code for that.
* [12:12] Drongle McMahon: You can't control it with different prims or materials, but it looks like you can for mesh faces within one material.
* [12:13] Drongle McMahon: Oh no ... automatic LODs are bad news anyway :-)
* [12:13] Vir Linden: Whether it's safe to count on the behavior for manually specified meshes: not sure, I can ping davep about it. If it works that way now, we wouldn't be likely to change it in the short term, but that's not quite the same as "you can safely rely on it"
* [12:13] Vir Linden: I'll pass the question along and update the group next week.
* [12:14] Drongle McMahon: I guess that's whyn I rraise it. If it is recognised as useful, then changes that break it can be avoided.
* [12:14] Vir Linden: right, will let you know.
* [12:15] Vir Linden: Next question: {repeat from last week 'cos I missed it and there's no transcipt} Any progress on fixing SVC-7727?
* [12:15] JIRA-helper: http://jira.secondlife.com/browse/SVC-7727 [#SVC-7727] Aditi grid problem. After changing my password to cause my inventory on Aditi to update, my inventory no longer saves changes made to it from session to session. - Second Life Bug Tracker 
* [12:15] Drongle McMahon: I could send him my demo meshes, maybe.
* [12:15] Nal (nalates.urriah): That is a real PITA 7727
* [12:15] Drongle McMahon: Yes ... VERY bad.
* [12:17] Drongle McMahon: I have UseHTTPInventory turned off and that avoids at leasy some of the losses, but I am a cloud.
* [12:18] Vir Linden: reading... some folks claim that clearing cache helps - has everyone tried it?
* [12:18] Nal (nalates.urriah): That gives you the mystical look....
* [12:18] Nal (nalates.urriah): Oh yeah
* [12:18] Drongle McMahon: Didn't help me.
* [12:18] Nal (nalates.urriah): me neighter
* [12:18] Gramma Fiddlesticks: No help for me either. =\
* [12:19] Nal (nalates.urriah): I've tried changing pw and waiting longer... that was no help either.
* [12:20] Drongle McMahon: Whatever it is, letting it onto Agni would be a disaster .... people have paid for their uploads there!
* [12:20] Nal (nalates.urriah): I can rez older stuff, but nothing new. Noting saves that I make in ADITI, and I can change appearance but it reverts back each login.
* [12:20] Vir Linden: Right, sounds like a mess.
* [12:21] Nal (nalates.urriah): Last Location nor work is another annoying problem
* [12:21] Nal (nalates.urriah): not working^
* [12:22] Vir Linden: hmm, might be the same issue - bad inventory server maybe
* [12:22] Drongle McMahon: You have to type it in to go anywhere at login.
* [12:22] Gramma Fiddlesticks: it started for me during open testing of DD.
* [12:23] Vir Linden: DD?
* [12:23] Gramma Fiddlesticks: Direct Delivery for Marketplace
* [12:23] Vir Linden: Ah, OK.
* [12:23] Aargle Zymurgy: *sigh* Direct Delivery. that one is still worrying me.
* [12:23] Gramma Fiddlesticks: don't know if it's actually related to that but it was when it started with me.
* [12:25] Prep Linden: I think aura linden might be able to look into this...I'm not sure if she is atm however.
* [12:25] Drongle McMahon: Password change -> inventory from Aditi triggered it for me and some others. It was ok before that while others were suffering.
* [12:25] Nal (nalates.urriah): Same here
* [12:26] Prep Linden: Apparently there's some inventory db configuration issue.
* [12:29] Vir Linden: OK, we'll pass that along.
* [12:29] Vir Linden: That's all we have for questions.
* [12:29] Vir Linden: Guess we can wrap up.
* [12:30] Nal (nalates.urriah): Suppose so...
* [12:30] Ashiri Sands: Thanks
* [12:30] Aargle Zymurgy: thanks for you time, guys
* [12:30] Vir Linden: Thanks everyone!
* [12:30] Gramma Fiddlesticks: Thanks for looking into the Aditi issues too.
* [12:30] Nal (nalates.urriah): Thanks Vir and Prep
* [12:30] Prep Linden: you bet, have a good one folks!
* [12:30] Keli Kyrie: Thank you Vir and Prep
* [12:30] Aargle Zymurgy: oh, is there someplace for discussion of direct delivery?
* [12:30] Drongle McMahon: Bye
* [12:31] Racush (racush.cheeky): seeya prep and vir
* [12:31] Yuzuru (yuzuru.jewell): thank you Lindens.
* [12:31] Gramma Fiddlesticks: oh. I'd like to know that too!