[visual] VisualModelImpl: add resetMaterial variable (#6057)

* [visual] VisualModelImpl: adds resetMaterial variable

* implement requested changes (rename, protected, getter)

---------

Co-authored-by: Hugo <hugo.talbot@sofa-framework.org>

Author: EulalieCoevoet

Sofa/Component/Visual/src/sofa/component/visual/VisualModelImpl.cpp

@@ -788,8 +788,9 @@ void VisualModelImpl::init()
     d_translation.setValue(Vec3Real());
     d_rotation.setValue(Vec3Real());
     d_scale.setValue(Vec3Real(1, 1, 1));
-}
 
+    m_savedMaterial = d_material.getValue();
+}
 
 void VisualModelImpl::initPositionFromVertices()
 {

Sofa/Component/Visual/src/sofa/component/visual/VisualModelImpl.h

@@ -346,6 +346,8 @@ class SOFA_COMPONENT_VISUAL_API VisualModelImpl : public core::visual::VisualMod
         d_edges.setValue(*e);
     }
 
+    const sofa::type::Material& getSavedMaterial() {return m_savedMaterial;}
+
     virtual void computePositions();
     virtual void computeMesh();
     virtual void computeNormals();
@@ -399,6 +401,9 @@ class SOFA_COMPONENT_VISUAL_API VisualModelImpl : public core::visual::VisualMod
 
     /// Internal buffer similar to @sa m_dirtyTriangles but to be used by topolgy Data @sa d_quads callback when points are removed.
     std::set< sofa::core::topology::BaseMeshTopology::QuadID> m_dirtyQuads;
+
+    /// Store the material information, to restore it after rendering with a specific material for selection (GUI related).
+    sofa::type::Material m_savedMaterial;
 };