OpenGL drawing methods

VisuGlExt — All objects drawn by V_Sim are defined in by a VisuGlExt object
VisuGlExtSet — Defines a storage object to handle a bunch of VisuGlExt objects.
VisuGlExtLined — Defines a common interface for VisuGlExt objects with line characteristics.
VisuGlExtNodes — Defines methods to draw a set of nodes.
VisuGlExtPairs — Draw links between nodes.
VisuGlExtFrame — Draw a frame with the representation of a color frame.
VisuGlExtBox — Draw a bounding box around nodes.
VisuGlExtBoxLegend — Draw a legend describing the box.
VisuGlExtAxes — Defines methods to draw axes.
VisuGlExtLegend — Draw a frame with the representation of each atom species, its name and the number of elements.
VisuGlExtShade — Draw a frame with the representation of a color shade.
VisuGlExtNodeVectors — Draw arrows at each node to represent forces, displacements, vibrations...
VisuGlExtForces — Draw arrows at each node to represent forces.
VisuGlExtGeodiff — Draw arrows at each node to represent geodiff.
VisuGlExtPlanes — Draw a list of VisuPlane.
VisuGlExtSurfaces — Defines methods to draw surfaces.
VisuGlExtMaps — Defines methods to draw maps.
VisuGlExtMapSet — Defines methods to draw maps that share a same VisuScalarField.
VisuGlExtInfos — give the capability to draw some information near each node.
VisuGlExtScale — Draw an arrow with a label.
VisuGlExtBg — Handle the background colour and the fog.
VisuGlExtMarks — Draw features on nodes, like measurement marks or highlights.
VisuGlExtPaths — Defines methods to draw paths.
VisuGlExtVibrations — Draw arrows at each node to represent vibrations.

All rendering is done via objects inherited from VisuExtension.