Add initial prototype.

3-mid/opengl/source/lean/text/private/opengl-glyphimpl-texture.ads

@@ -0,0 +1,99 @@
+with
+     openGL.Texture,
+     freetype_c.FT_GlyphSlot;
+
+private
+with
+     openGL.Geometry.lit_textured,
+     openGL.Primitive.indexed,
+     GL;
+
+package openGL.GlyphImpl.texture
+--
+--  Implements a texture-based glyph.
+--
+is
+   type Item is new GlyphImpl.item with private;
+   type View is access all Item'Class;
+
+
+   ---------
+   --  Types
+   --
+
+   type Vertex is
+      record
+         Site   : Vector_3;
+         Coords : Coordinate_2D;
+      end record;
+
+   type Quad_t is
+      record
+         NW, NE,
+         SW, SE  : Vertex;
+         Advance : Vector_3;
+      end record;
+
+
+   ---------
+   --  Forge
+   --
+   function new_GlyphImpl (glyth_Slot       : in freetype_c.FT_GlyphSlot.item;
+                           texture_Id       : in openGL.Texture.texture_Name;
+                           xOffset, yOffset : in Integer;
+                           Width,   Height  : in Integer) return GlyphImpl.texture.view;
+   --
+   --  glyth_Slot:       The Freetype glyph to be processed.
+   --  texture_Id:       The Id of the texture that this glyph will be drawn in.
+   --  xOffset, yOffset: The x any y offset into the parent texture to draw this glyph.
+   --  Width,   Height:  The width and height (number of rows) of the parent texture.
+
+
+   --------------
+   --  Attributes
+   --
+
+   function Quad (Self : in Item;   Pen : in Vector_3) return Quad_t;
+
+
+   --------------
+   --  Operations
+   --
+
+   function renderImpl (Self : in Item;   Pen        : in Vector_3;
+                                          renderMode : in Integer) return Vector_3;
+   --
+   --  Pen:         The current pen position.
+   --  renderMode:  Render mode to display.
+   --
+   --  Returns the advance distance for this glyph.
+
+
+   -------------
+   --  Protected - for derived class use only.
+   --
+
+   procedure ResetActiveTexture;
+   --
+   --  Reset the currently active texture to zero to get into a known
+   --  state before drawing a string. This is to get around possible threading issues.
+
+
+
+private
+
+   type Item is new GlyphImpl.item with
+      record
+         destWidth,                                             -- The width and height of the glyph 'image'.
+         destHeight  :        GL.GLint;
+
+         Corner      :        Vector_3;                         -- Vector from the pen site to the top left of the pixmap.
+
+         UV          :        Coordinates_2D (1 .. 2);          -- The texture co-ords of this glyph within the texture.
+         glTextureID :        openGL.texture.texture_Name;      -- The texture index that this glyph is contained in.
+
+         Geometry    : access Geometry.lit_textured.item;
+         Primitive   :        openGL.Primitive.indexed.view;
+      end record;
+
+end openGL.GlyphImpl.texture;