[GUI] Fix display of Visual's scaleV

[arntanguy]

This PR modifies mc_rtc::gui::Visual to publish the scaleV property (scale along x,y,z axes) instead of the scale property (global scale for all axes). This allows the display interface to properly display scaled meshes. For example:

  gui()->addElement({"Scale"},
        mc_rtc::gui::NumberSlider("x", [this]() { return scale.x(); }, [this](double x) { scale.x() = x; }, 0., 10.),
        mc_rtc::gui::NumberSlider("y", [this]() { return scale.y(); }, [this](double y) { scale.y() = y; }, 0, 10),
        mc_rtc::gui::NumberSlider("z", [this]() { return scale.z(); }, [this](double z) { scale.z() = z; }, 0, 10)
      );
  auto & robot = this->robot();
  for (auto & visual : const_cast<mc_rbdyn::RobotModule &>(robot.module())._visual)
  {
    for (size_t i = 0; i < visual.second.size(); i++)
    {
      auto & v = visual.second[i];
      gui()->addElement({"Human", "Visuals"},
          mc_rtc::gui::Visual(fmt::format("{}_{}", visual.first, i), [&v]() { return v;},
          [this, &robot, &v, &visual]() {
            if (v.geometry.type == rbd::parsers::Geometry::MESH)
            {
              auto & mesh = boost::get<rbd::parsers::Geometry::Mesh>(v.geometry.data);
              mesh.scaleV = scale;
            }
            return v.origin * robot.frame(visual.first).position();
          }));
    }
  }

This publishes all of the robot visuals and allows to rescale individiual axes of its meshes online. Note that this is displayed correctly in rviz, but currently not in magnum (as the scale is taken into account only at mesh creation).

In addition, I do not see the point of keeping both scale and scaleV properties. They are somewhat contradictory, and scaleV contains all of the necessary information. Thus I suggest the corresponding PR in RBDyn to remove scale.

[gergondet]

Hi @arntanguy

No problem with this PR except for the small backward compatibility issue

In addition, I do not see the point of keeping both scale and scaleV properties. They are somewhat contradictory, and scaleV contains all of the necessary information. Thus I suggest the corresponding PR in RBDyn to remove scale

This was done to introduce the vector form of scale without breaking existing code but it should be fine to retire scale (as suggested in the RBDyn PR)

[gergondet]

To keep it compatible if people update mc_rtc without updating the GUI implementations

Suggested change

	m.scaleV = config("scaleV");
	if(auto scale = config.find("scale"))
	{
	m.scale = scale->operator<double>();
	m.scaleV.setConstant(m.scale);
	}
	else
	{
	m.scaleV = config("scaleV");
	m.scale = m.scaleV(0);
	}

[arntanguy]

m.scale won't exist after the RBDyn PR, so I'm not sure what you are suggesting here?

[gergondet]

Oh yes. I guess we can skip this then release a new version of mc_rtc that does not require scale and then release a version of RBDyn without scale?

[arntanguy]

Yes as is it works without updating RBDyn, it's just less confusing not to have both properties in the future ;)

[gergondet]

Thanks @arntanguy

If everything builds feel free to (in that order):

• merge this
• merge [panel/visual] Fix display of scaleV mc_rtc_ros#39
• merge Remove Geometry::scale  RBDyn#119

I'll release new versions of RBDyn/mc_rtc/mc_rtc_ros on Monday