Opacity is broken in Scalable Rendering Mode

[JustinPrivitera]

In 3.4.1 blueOS and toss4, scalable rendering mode with non-100% opacity is broken.

Here is a pseudocolor plot of d from multi_curv3d.silo with the opacity set to 20% in default rendering mode:

Here is the same plot with scalable rendering mode enabled:

Here is a filled boundary plot of mat1 from multi_curv3d.silo with the opacity set to 20% in default rendering mode:

Here is the same plot with scalable rendering mode enabled:

Another angle:

These plots worked correctly in 3.3.3.

To reproduce:

1. run visit in parallel
2. open multi_curv3d.silo
3. make a pseudocolor plot of d
4. change opacity to 20%
5. open options/rendering and turn scalable rendering mode to "always"

There are some large datasets on the SCF under /usr/workspace/visit/visit/bug_data that have these issues; we should ensure that for all of them this issue is resolved before marking this ticket as resolved. It is possible that those datasets may have additional issues that are not captured here.

[markcmiller86]

Yeah, I have a bad feeling we introduced some transparency issues in 3.4 with VTK-9.