Vertices vertex object and related functions. Vertices are points used as endpoints of #GtsSegment. They are derived from #GtsPoint. Casts @klass to #GtsVertexClass. @klass: a descendant of #GtsVertexClass. Casts @obj to #GtsVertex. @obj: a descendant of #GtsVertex. Evaluates to %TRUE if @obj is a descendant of #GtsVertex, %FALSE otherwise. @obj: a pointer to test. The vertex class. No virtual functions are associated. @parent_class: @intersection_attributes: The vertex object. @p: The parent object. @segments: Contains all the #GtsSegment using this vertex as one of their endpoints. @Returns: @klass: @x: @y: @z: @Returns: @v: @Returns: @v: @surface: @Returns: @v: @sever: @Returns: @v1: @v2: @Returns: @v: @with: @v: @list: @surface: @Returns: @v: @list: @Returns: @v: @surface: @list: @Returns: @v: @surface: @Returns: @v: @e: @Returns: @segments: @Returns: @vertices: @epsilon: @check: @Returns: