Merge pull request #921 from S-Dafarra/fix/VectorVizSlowedDown

Fixed the slowing down of the visualizer when updating the vectors.

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 - Fixed the conversion from irrlicht pixels to iDynTree pixels. Fixed a typo in the environment method of the visualizer. Fixed the running of two visualizer instances in the same process (https://github.com/robotology/idyntree/pull/903).
+- Fixed the update of the vectors in the visualization that caused the FPS to drop (https://github.com/robotology/idyntree/pull/921).
 
 ## [4.1.0] - 2021-07-22
 
@@ -411,7 +412,7 @@ As this is an `inline` function, this modification does not affect `iDynTree`'s
 - The `IVector`, `IRawVector`, `IMatrix` and `IRawMatrix` interfaces have been removed for performance reasons, 
   see https://github.com/robotology/idyntree/issues/98#issuecomment-158823148 . If you want to write generic 
   code in C++ you can rely on templates, and on Matlab and Python you can rely on the native dynamic type system. 
-   
+
 - All the core classes that have a fixed size (`Position`, `Rotation`, `Transform`, `SpatialMotionVector`, etc, etc) are 
   not initialized by their empty constructor for performance reasons, see https://github.com/robotology/idyntree/issues/98#issuecomment-158795881 .
   From now on, make sure that initialize them before any use. Most of those classes should have a `zero()` method to

src/visualization/src/VectorsVisualization.cpp

@@ -46,8 +46,6 @@ void VectorsVisualization::drawVector(size_t vectorIndex)
 
     irr::core::vector3df arrowRotation = idyntree2irr_rot(arrowRotationMatrix);
 
-    irr::scene::ISceneNode * frameNode = m_smgr->addEmptySceneNode();
-
     irr::scene::IMesh* arrowMesh = m_smgr->getGeometryCreator()->createArrowMesh(4, 8, arrowHeight, 0.9f * arrowHeight,
                                                                                  arrowWidth, 2.0f * arrowWidth);
 
@@ -57,6 +55,7 @@ void VectorsVisualization::drawVector(size_t vectorIndex)
     }
     else
     {
+        irr::scene::ISceneNode * frameNode = m_smgr->addEmptySceneNode();
         m_vectors[vectorIndex].visualizationNode = m_smgr->addMeshSceneNode(arrowMesh,frameNode);
     }
     m_vectors[vectorIndex].visualizationNode->setPosition(arrowPosition);