Add initial prototype.

3-mid/opengl/source/lean/opengl-frame_buffer.ads

@@ -0,0 +1,61 @@
+with
+     openGL.Texture;
+
+package openGL.Frame_Buffer
+is
+
+   type Item is tagged private;
+
+   null_Buffer : constant Item;
+
+
+   ---------
+   --- Forge
+   --
+
+   package Forge
+   is
+      function to_Frame_Buffer return Item;
+      function to_Frame_Buffer (Width,
+                                Height : in Positive) return Item;
+   end Forge;
+
+   procedure destruct (Self : in out Item);
+
+
+   --------------
+   --- Attributes
+   --
+   subtype Buffer_Name is GL.GLuint;     -- An openGL frame buffer 'Name'.
+
+   function  Name        (Self : in     Item)     return Buffer_Name;
+
+   function  Texture     (Self : in     Item)     return openGL.Texture.Object;
+   procedure Texture_is  (Self : in out Item;   now : in openGL.Texture.Object);
+
+   function  is_complete (Self : in     Item)     return Boolean;
+
+
+   --------------
+   --- Operations
+   --
+
+   procedure enable  (Self : in Item);
+   procedure disable (Self : in Item);
+   --
+   -- Unbind the frame buffer so rendering will return to the backbuffer.
+
+
+
+private
+
+   type Item is tagged
+      record
+         Name    : aliased buffer_Name;
+         Texture :         openGL.Texture.Object;
+      end record;
+
+   null_Buffer : constant Item := (Name    => 0,
+                                   Texture => openGL.Texture.null_Object);
+
+end openGL.Frame_Buffer;