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IDProjectCategoryView StatusDate SubmittedLast Update
0015960ParaView(No Category)public2016-01-27 17:132016-03-02 20:04
ReporterAlan Scott 
Assigned ToUtkarsh Ayachit 
PrioritynormalSeverityminorReproducibilityhave not tried
StatusclosedResolutionfixed 
PlatformOSOS Version
Product Version5.0 
Target Version5.0.1Fixed in Version5.0.1 
Summary0015960: Squirt compression issue, using transparency
DescriptionThere is a weird compression bug we are seeing, remote server, Mesa3d (OGL2). Utkarsh has replicated.

* master (basically 5.0.0), Linux, remote server, 1 process.
* Edit/ Settings/ Render View/ Remote Render Threshold set to 0.
* (Image compression should be default, which is Squirt compression, level 3.)
* OK.
* Sources/ Wavelet. Apply. Surface. Color by RTData.
* Color Editor/ Enable opacity mapping for surfaces.

There will be banding in the image. This is a bug. I will add a screenshot.

TagsNo tags attached.
ProjectSandia
Topic Name
Typeincorrect functionality
Attached Filesjpg file icon badOpacity.jpg [^] (251,574 bytes) 2016-01-27 17:13

 Relationships

  Notes
(0035685)
Alan Scott (manager)
2016-01-27 17:48

 I forgot - the workaround for this issue is to change squirt compression to zlib compression.
(0035699)
Utkarsh Ayachit (administrator)
2016-02-05 09:48

 Proving a different workaround instead of updating the SQUIRT algorithm to a improve alpha precision, we now have a new compression algorithm that's recommended for use LZ4. Default will be changed to LZ4.


Merge request: https://gitlab.kitware.com/paraview/paraview/merge_requests/598 [^]
(0035777)
Alan Scott (manager)
2016-02-24 17:06

 Make LZ4 the default.
(0035797)
Utkarsh Ayachit (administrator)
2016-02-25 10:19
edited on: 2016-02-25 10:19

 LZ4 is now default in 5.0.1.

MR: https://gitlab.kitware.com/paraview/paraview/merge_requests/659 [^]
(0035798)
Alan Scott (manager)
2016-02-25 20:56

 No, this isn't correct. But, I have really good news, I now know why. Follow the following steps EXACTLY to replicate what the problem is.

* Delete your .config files (-dr is probably ok).
* Remote server, 2 ranks, Linux, master.
* OK to make ParaView a bit bigger, if you desire.
* Edit/ Settings/ Advanced/ Render View.
* Remote render threshold 0. OK.
* Sources/ Wavelet. Apply. Representation Surface. Color by RTData.
* Color Editor. Enable opacity mapping for surfaces.
<<Bug>> You will see banding. Nothing you do will change this. I.e., drag wavelet around with the mouse. Further, notice that LOD desimation is NOT occurring.
* Edit/ Settings/ Advanced/ Render View. (You should already have advanced on from before).
* Change Image Compression amount from 3 to 4 (i.e., more compression). Apply.

The banding has gone away!

* Change image compression back to 3, apply. Now, rotate the object with the mouse. Notice that compression artifacts are visible when the mouse is down, but not for still rendering.

<<Bug>> What is happening is that ParaView is starting always compressing the view, whether we have a mouse down render or a still render. That is the root cause of our issue. By changing the Image Compression, ParaView then moves to correct behavior - Image compression when mouse is down, no compression the rest of the time.
(0035799)
Alan Scott (manager)
2016-02-25 21:11

 I tried this with Squirt compression, and it just remains compressed all the time. Moving compression to "5", it appears that the still rendering compression is 3, and the mouse down compression is 5. Weird.
(0035801)
Utkarsh Ayachit (administrator)
2016-02-25 22:40

 Squirt will always have that issue for alpha. It's independent of compression level. The real bug was that LZ4 was not getting picked as default despite the fact that the settings said it was LZ4. When you change the compression value, ParaView switched to using LZ4 with the compression value you specified and it started working.

Fixed that. Default is now truly LZ4.
(0035802)
Utkarsh Ayachit (administrator)
2016-02-25 22:41

 https://gitlab.kitware.com/paraview/paraview/merge_requests/663 [^]
(0035807)
Alan Scott (manager)
2016-03-02 20:04

 Looks good. Tested remote server, Linux, 5.0.1-RC1

 Issue History
Date Modified Username Field Change
2016-01-27 17:13 Alan Scott New Issue
2016-01-27 17:13 Alan Scott File Added: badOpacity.jpg
2016-01-27 17:48 Alan Scott Note Added: 0035685
2016-01-27 17:48 Alan Scott Description Updated
2016-01-28 11:51 Utkarsh Ayachit Assigned To => Utkarsh Ayachit
2016-01-28 11:51 Utkarsh Ayachit Status backlog => todo
2016-01-28 11:52 Utkarsh Ayachit Target Version => 5.0.1
2016-01-28 16:41 Utkarsh Ayachit Status todo => active development
2016-02-05 09:48 Utkarsh Ayachit Note Added: 0035699
2016-02-05 09:48 Utkarsh Ayachit Status active development => customer review
2016-02-05 09:48 Utkarsh Ayachit Fixed in Version => 5.0.1
2016-02-05 09:48 Utkarsh Ayachit Resolution open => fixed
2016-02-24 17:06 Alan Scott Note Added: 0035777
2016-02-24 17:06 Alan Scott Status customer review => todo
2016-02-25 10:19 Utkarsh Ayachit Note Added: 0035797
2016-02-25 10:19 Utkarsh Ayachit Status todo => customer review
2016-02-25 10:19 Utkarsh Ayachit Note Edited: 0035797
2016-02-25 20:56 Alan Scott Note Added: 0035798
2016-02-25 20:56 Alan Scott Status customer review => todo
2016-02-25 21:11 Alan Scott Note Added: 0035799
2016-02-25 22:40 Utkarsh Ayachit Note Added: 0035801
2016-02-25 22:41 Utkarsh Ayachit Note Added: 0035802
2016-02-25 22:41 Utkarsh Ayachit Status todo => gatekeeper review
2016-02-29 16:34 Utkarsh Ayachit Status gatekeeper review => customer review
2016-03-02 20:04 Alan Scott Note Added: 0035807
2016-03-02 20:04 Alan Scott Status customer review => closed

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