Bond rotation slow when ribbon shown

[Tom Goddard]

When rotating a sidechain bond with the mouse with ribbon display, the rotation is slow because the full ribbon is being recomputed at every step. Would like the ribbon not to recompute shape. None of the backbone atoms used for the ribbon computation move during the bond rotation. Perhaps the code that cause the ribbon change notification when an atom coordinate changes could check if the atom is one of those used for the ribbon calculation.

This problem makes bond rotation unusable with virtual reality if a ribbon is shown.

[Conrad Huang]

bc251638 implements this by adding an in_ribbon atom attribute that tracks whether the atom was used for ribbon calculations. Changes to atomic coordinates now only mark "ribbon_changed" in the graphics state if atom->in_ribbon is true.

Can you please check to see if this addresses the performance issues? Thanks.

[goddard@…]

Works nicely, no ribbon update when rotating sidechain bonds on 1aon.

[Conrad Huang]

Verified to work in VR