Preserve volume per-vertex colors in sessions

[goddard@…]

The following bug report has been submitted:
Platform:        Darwin-19.5.0-x86_64-i386-64bit
ChimeraX Version: 1.1.dev202006100038 (2020-06-10 00:38:38 UTC)
Description
Session saving does not preserve volume per-vertex coloring when that coloring was computed by sampling another map which was closed before saving the session.  The session should remember the per-vertex colors if it is not possible to recompute them.

Log:
UCSF ChimeraX version: 1.1.dev202006100038 (2020-06-10)  
© 2016-2020 Regents of the University of California. All rights reserved.  

> open /Users/goddard/ucsf/chimerax/src/bundles/surface/test.cxs format
> session

Log from Thu Jun 11 10:26:14 2020UCSF ChimeraX version: 1.1.dev202006100038
(2020-06-10)  
© 2016-2020 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open /Users/goddard/Downloads/ChimeraX/EMDB/emd_0632.map format ccp4

Opened emd_0632.map, grid size 180,180,180, pixel 0.837, shown at level
0.0349, step 1, values float32  

> volume gaussian #1 sDev 2

> color sample #1 map #2

Map values for surface "surface": minimum 0.001353, mean 0.01204, maximum
0.02183  

> close #2

> save test.cxs

opened ChimeraX session  




OpenGL version: 4.1 ATI-3.9.15
OpenGL renderer: AMD Radeon Pro Vega 20 OpenGL Engine
OpenGL vendor: ATI Technologies Inc.Hardware:

    Hardware Overview:

      Model Name: MacBook Pro
      Model Identifier: MacBookPro15,3
      Processor Name: 8-Core Intel Core i9
      Processor Speed: 2.4 GHz
      Number of Processors: 1
      Total Number of Cores: 8
      L2 Cache (per Core): 256 KB
      L3 Cache: 16 MB
      Hyper-Threading Technology: Enabled
      Memory: 32 GB
      Boot ROM Version: 1037.120.87.0.0 (iBridge: 17.16.15300.0.0,0)

Software:

    System Software Overview:

      System Version: macOS 10.15.5 (19F101)
      Kernel Version: Darwin 19.5.0
      Time since boot: 1 day 18:17

Graphics/Displays:

    Intel UHD Graphics 630:

      Chipset Model: Intel UHD Graphics 630
      Type: GPU
      Bus: Built-In
      VRAM (Dynamic, Max): 1536 MB
      Vendor: Intel
      Device ID: 0x3e9b
      Revision ID: 0x0002
      Automatic Graphics Switching: Supported
      gMux Version: 5.0.0
      Metal: Supported, feature set macOS GPUFamily2 v1

    Radeon Pro Vega 20:

      Chipset Model: Radeon Pro Vega 20
      Type: GPU
      Bus: PCIe
      PCIe Lane Width: x8
      VRAM (Total): 4 GB
      Vendor: AMD (0x1002)
      Device ID: 0x69af
      Revision ID: 0x00c0
      ROM Revision: 113-D2060I-087
      VBIOS Version: 113-D20601MA0T-016
      Option ROM Version: 113-D20601MA0T-016
      EFI Driver Version: 01.01.087
      Automatic Graphics Switching: Supported
      gMux Version: 5.0.0
      Metal: Supported, feature set macOS GPUFamily2 v1
      Displays:
        Color LCD:
          Display Type: Built-In Retina LCD
          Resolution: 2880 x 1800 Retina
          Framebuffer Depth: 24-Bit Color (ARGB8888)
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Automatically Adjust Brightness: No
          Connection Type: Internal

PyQt version: 5.12.3
Compiled Qt version: 5.12.4
Runtime Qt version: 5.12.8

[Tom Goddard]

This will have to rely on the recomputed contour surface having exactly the same vertices, or it could save the surface. Even if the surface is saved any threshold level change will immediately lose the coloring.