Add method to draw 3D label in Irrlicht. Clean up drawArrow signature

src/chrono_irrlicht/ChIrrTools.cpp

@@ -1085,11 +1085,11 @@ void drawCoordsys(ChVisualSystemIrrlicht* vis, const ChCoordsys<>& coord, double
 // Draw a line arrow in 3D space with given color.
 // -----------------------------------------------------------------------------
 void drawArrow(ChVisualSystemIrrlicht* vis,
-               ChVector3d start,
-               ChVector3d end,
-               ChVector3d plane_normal,
+               const ChVector3d& start,
+               const ChVector3d& end,
+               const ChVector3d& plane_normal,
                bool sharp,
-               ChColor col,
+               const ChColor& col,
                bool use_Zbuffer) {
     drawSegment(vis, start, end, col, use_Zbuffer);  // main segment
     ChVector3d dir = (end - start).GetNormalized();
@@ -1107,6 +1107,24 @@ void drawArrow(ChVisualSystemIrrlicht* vis,
     drawSegment(vis, end, p2, col, use_Zbuffer);  // arrow segment 2
 }
 
+// -----------------------------------------------------------------------------
+// Draw a label in 3D scene at given position.
+// -----------------------------------------------------------------------------
+void drawLabel3D(ChVisualSystemIrrlicht* vis,
+               const std::string& text,
+               const ChVector3d& position,
+               const ChColor& color,
+               bool use_Zbuffer) {
+    irr::core::position2di spos =
+        vis->GetSceneManager()->getSceneCollisionManager()->getScreenCoordinatesFrom3DPosition(
+            irr::core::vector3dfCH(position));
+    auto font = vis->GetGUIEnvironment()->getFont(GetChronoDataFile("fonts/arial8.xml").c_str());
+    if (font) {
+        font->draw(text.c_str(), irr::core::rect<irr::s32>(spos.X - 15, spos.Y, spos.X + 15, spos.Y + 10),
+                   tools::ToIrrlichtSColor(color));
+    }
+}
+
 }  // end namespace tools
 }  // end namespace irrlicht
 }  // end namespace chrono

src/chrono_irrlicht/ChIrrTools.h

@@ -257,15 +257,22 @@ ChApiIrr void drawCoordsys(ChVisualSystemIrrlicht* vis,
                            bool use_Zbuffer = false);
 
 /// Draw a line arrow in 3D space with given color.
-ChApiIrr void drawArrow(ChVisualSystemIrrlicht* vis,           ///< visual system
-                        ChVector3d start,                      ///< arrow start point
-                        ChVector3d end,                        ///< arrow end point
-                        ChVector3d plane_normal = VECT_Y,      ///< normal to plane containing arrow segments
-                        bool sharp = false,                    ///< set arrow shape as 'sharp' or 'wide'
-                        ChColor col = ChColor(1.f, 1.f, 1.f),  ///< color
-                        bool use_Zbuffer = false               ///< use Z buffer
+ChApiIrr void drawArrow(ChVisualSystemIrrlicht* vis,                  ///< visual system
+                        const ChVector3d& start,                      ///< arrow start point
+                        const ChVector3d& end,                        ///< arrow end point
+                        const ChVector3d& plane_normal = VECT_Y,      ///< normal to plane containing arrow segments
+                        bool sharp = false,                           ///< set arrow shape as 'sharp' or 'wide'
+                        const ChColor& col = ChColor(1.f, 1.f, 1.f),  ///< color
+                        bool use_Zbuffer = false                      ///< use Z buffer
 );
 
+/// Draw a label in 3D scene at given position.
+ChApiIrr void drawLabel3D(ChVisualSystemIrrlicht* vis,
+                        const std::string& text,
+                        const ChVector3d& position,
+                        const ChColor& color = ChColor(0.f, 0.f, 0.f),
+                        bool use_Zbuffer = false);
+
 }  // end namespace tools
 
 /// @} irrlicht_module

src/chrono_irrlicht/ChVisualSystemIrrlicht.cpp

@@ -63,7 +63,7 @@ ChVisualSystemIrrlicht::ChVisualSystemIrrlicht()
     m_device_params.LoggingLevel = irr::ELL_INFORMATION;
 
     // Create the GUI
-    m_gui = std::unique_ptr<ChIrrGUI>(new ChIrrGUI());
+    m_gui = std::make_unique<ChIrrGUI>();
 
     // Create shared meshes
     sphereMesh = createEllipticalMesh(1.0, 1.0, -2, +2, 0, 15, 8);