Add initial prototype.

3-mid/opengl/source/lean/model/opengl-model-grid.ads

@@ -0,0 +1,43 @@
+with
+     openGL.Geometry.colored;
+
+
+package openGL.Model.grid
+--
+--  Models a grid.
+--
+--  TODO: Rename to 'line_Grid'.
+is
+   type Item is new Model.item with private;
+   type View is access all Item'Class;
+
+
+   ---------
+   --- Forge
+   --
+
+   function new_grid_Model (Color  : openGL.Color;
+                            Width  : Integer;
+                            Height : Integer) return View;
+
+   --------------
+   --- Attributes
+   --
+
+   overriding
+   function to_GL_Geometries (Self : access Item;   Textures : access Texture.name_Map_of_texture'Class;
+                                                    Fonts    : in     Font.font_id_Map_of_font) return Geometry.views;
+
+
+private
+
+   type Item is new Model.item with
+      record
+         Color    : openGL.rgb_Color;
+         Vertices : openGL.Geometry.colored.Vertex_array_view;
+         Geometry : openGL.Geometry.colored.view;
+         Width,
+         Height   : Positive;
+      end record;
+
+end openGL.Model.grid;