Add initial prototype.

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

@@ -0,0 +1,41 @@
+package openGL.Model.box
+--
+--  Provides an abstract model of a box.
+--
+is
+   type Item is abstract new Model.item with private;
+
+   type Side is (Front, Rear,
+                 Upper, Lower,
+                 Left,  Right);
+
+   function Size (Self : in Item) return Vector_3;
+
+
+
+private
+
+   type Item is abstract new Model.item with
+      record
+         Size : Vector_3;
+      end record;
+
+
+   type site_Id is ( Left_Lower_Front, Right_Lower_Front,
+                    Right_Upper_Front,  Left_Upper_Front,
+                    Right_Lower_Rear,   Left_Lower_Rear,
+                     Left_Upper_Rear,  Right_Upper_Rear);
+
+   type Sites is array (site_Id) of Site;
+
+
+   front_Normal : constant Vector_3 := [ 0.0,  0.0,  1.0];
+   rear_Normal  : constant Vector_3 := [ 0.0,  0.0, -1.0];
+   upper_Normal : constant Vector_3 := [ 0.0,  1.0,  0.0];
+   lower_Normal : constant Vector_3 := [ 0.0, -1.0,  0.0];
+   left_Normal  : constant Vector_3 := [-1.0,  0.0,  0.0];
+   right_Normal : constant Vector_3 := [ 1.0,  0.0,  0.0];
+
+   function vertex_Sites (Self : in Item'Class) return Sites;
+
+end openGL.Model.box;