support viewport selection in maya2019 VP2 (retry)

[pilarmolinalopez]

Description

Implements VP2 selection in maya2019 thanks to the new MPxDrawOverride::userSelect() interface
(Duplicated of pull request #108. Now merging into develop branch. Discard pull request #108)

Changelog

Added

• Implementation of new ProxyDrawOverride::userSelect() provided with maya2019
• Implementation of ProxyShape::getShapeSelectionMask()

Checklist (Please do not remove this line)

• Make sure the Title and Description of the PR make sense and provide sufficient context for your work
• Do any added files have the correct AL Apache Licence Header?
• Are there Doxygen comments in the headers?
• Are any new features, behaviour changes documented in the .md format documentation?
• Have you added, updated tests to cover new features and behaviour changes?
• Have you filled out at least one changelog entry?

[murphyeoin]

Hi Pilar, thanks for opening the new PR...I gave it a quick test in PR95, and am getting a segfault deep in UsdImagingGLHdEngine::TestIntersectionBatch - could be something on our end, the build of USD/AL_USDMaya etc - will give it another try tomorrow.
Eoin

[pilarmolinalopez]

Hi Eoin, I haven't experienced any segfault like that one. We have been seeing some random crashes but not in that part of the code. These same crashes also happen when using the commands for selecting (instead of selecting in viewport), so I assume they are not related to the ProxyDrawOverride::userSelect() code. I'm also testing in PR95. Let me know if you need me to test anything.

[murphyeoin]

All good, problem looks like it's related to mixing compilers in USD and AL_USDMaya on our side. Thank you!