Add toolbar toggles for OpenSim::ModelDisplayHints

[adamkewley]

Related discussion: #886 by @VDB-Bram

The OpenSim::ModelDisplayHints class contains toggles for:

• wrap_geometry - already available
• contact_geometry - already available
• path_geometry - unused in opensim-core (v4.5)
• path_points (e.g. https://github.com/opensim-org/opensim-core/blob/a917fa05c9b053eba7d0e478776a626de7ec134e/OpenSim/Simulation/Model/GeometryPath.cpp#L231)
• markers - already available
• forces - now available (467aabb)
• frames - already available
• labels - unused in opensim-core (v4.5)
• debug_geometry - unused in opensim-core (v4.5)

But the toolbar in OSC's model editor only shows buttons for frames, markers, wrap_geometry, and contact_geometry. It would be nice to have buttons for all of them (although the remainder aren't used as often!).

[adamkewley]

467aabb adds support for toggling forces

[adamkewley]

I will skip adding ui support for path_points - from what I guess, the main reason it's there is as a performance optimization. Paths that are wrapped over wrap geometry can contain a very large amount of wrap points (+ connecting cylinders). By disabling path points you can almost half the amount of rendered geometry. However, rendering performance isn't practically a concern in OSC, which can render thousands of objects quickly due to its automatic instance batching implementation.

Supporting toggling path_points would also have the unintended side-effect of making OpenSim::PathPoints harder to visually edit (because they won't be put into the 3D viewport, so the UI won't be able to link user edits in the navigator etc. to something they see in a viewport).

path_geometry would potentially be a nice one to support. However, I'll have to be a little bit careful about it. Although it's supplied by OpenSim, OpenSim doesn't actually use it to prevent OpenSim::GeometryPath from emitting decorations. This means that, if OSC did support it, it might end up being inconsistent with other programs/scripts (which implicitly don't support it, because they're probably relying on OpenSim to process it).

[adamkewley]

This is now complete and will be shipped with the upcoming release

I have decided that support for the other flags (e.g. path_geometry) isn't so useful, or could even be confusing because other platforms won't support it. The user can currently toggle path geometry by right-clicking the ForceSet and using the Display menu.