Add initial prototype.

3-mid/opengl/source/opengl-renderer.ads

@@ -0,0 +1,30 @@
+package openGL.Renderer
+--
+-- Provides a base class for all renderers.
+--
+is
+
+   type Item is abstract tagged limited private;
+   type View is access all Item'Class;
+
+
+   --  Attributes
+   --
+   procedure Background_is (Self : in out Item;   Now     : in openGL.lucid_Color);
+   procedure Background_is (Self : in out Item;   Now     : in openGL.Color;
+                                                  Opacity : in Opaqueness := 1.0);
+
+   --  Operations
+   --
+   procedure clear_Frame (Self : in Item);
+
+
+
+private
+
+   type Item is abstract tagged limited
+      record
+         Background : openGL.rgba_Color;
+      end record;
+
+end openGL.Renderer;