Add initial prototype.

3-mid/opengl/source/lean/text/opengl-glyph.ads

@@ -0,0 +1,68 @@
+with
+     freeType_c.FT_GlyphSlot,
+     openGL.GlyphImpl;
+
+package openGL.Glyph
+--
+--  Glyph is the base class for openGL glyphs.
+--
+--  It provides the interface between Freetype glyphs and their openGL
+--  renderable counterparts.
+--
+--  This is an abstract class and derived classes must implement the 'Render' function.
+--
+is
+   type Item is abstract tagged private;
+
+
+   ---------
+   --  Forge
+   --
+
+   procedure destruct (Self : in out Item);
+
+
+   --------------
+   --  Attributes
+   --
+   function Advance (Self : in Item) return Real;                   -- Return the advance width for this glyph.
+   function BBox    (Self : in Item) return Bounds;                 -- Return the bounding box for this glyph.
+   function Error   (Self : in Item) return GlyphImpl.Error_Kind;   -- Return the current error code.
+
+
+   --------------
+   --- Operations
+   --
+   function render (Self : in Item;   Pen        : in Vector_3;
+                                      renderMode : in Integer) return Vector_3
+                    is abstract;
+   --
+   --  Renders this glyph at the current pen position.
+   --
+   --  Pen:        The current pen position.
+   --  renderMode: Render mode to display.
+   ---
+   --  Returns the advance distance for this glyph.
+
+
+
+private
+
+   type Item is abstract tagged
+      record
+         Impl : GlyphImpl.view;    -- Internal FTGL FTGlyph implementation object. For private use only.
+      end record;
+
+
+   procedure define (Self : in out Item;   glyth_Slot : in freetype_c.FT_GlyphSlot.item);
+   --
+   --  glyth_Slot: The Freetype glyph to be processed.
+
+
+   procedure define (Self : in out Item;   pImpl : in GlyphImpl.view);
+   --
+   --  Internal FTGL FTGlyph constructor. For private use only.
+   --
+   --  pImpl: An internal implementation object. Will be destroyed upon FTGlyph deletion.
+
+end openGL.Glyph;