Add initial prototype.

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

@@ -0,0 +1,128 @@
+with
+     openGL.Texture,
+     openGL.GlyphImpl.texture,
+
+     freetype_c.FT_GlyphSlot,
+
+     ada.Containers.Vectors;
+
+private
+with
+     GL;
+
+
+package openGL.FontImpl.texture
+--
+--  Implements a texture font.
+--
+is
+   type Item is new FontImpl.item with private;
+   type View is access all Item'Class;
+
+
+   ---------
+   --  Forge
+   --
+
+   function  to_FontImpl_texture (ftFont            : access openGL.Font.item'Class;
+                                  fontFilePath      : in     String)  return fontImpl.texture.item;
+
+   function new_FontImpl_texture (ftFont            : access openGL.Font.item'Class;
+                                  fontFilePath      : in     String)  return access fontImpl.texture.item'Class;
+
+   function  to_FontImpl_texture (ftFont            : access openGL.Font.item'Class;
+                                  pBufferBytes      : in     unsigned_char_Pointer;
+                                  bufferSizeInBytes : in     Natural) return fontImpl.texture.item;
+
+   function new_FontImpl_texture (ftFont            : access openGL.Font.item'Class;
+                                  pBufferBytes      : in     unsigned_char_Pointer;
+                                  bufferSizeInBytes : in     Natural) return fontImpl.texture.view;
+   overriding
+   procedure destruct (Self : in out Item);
+
+
+   --------------
+   --  Attributes
+   --
+
+   overriding
+   function FaceSize (Self : access Item;   Size     : in Natural;
+                                            x_Res,
+                                            y_Res    : in Natural := 72) return Boolean;
+   --
+   --  Set the char size for the current face.
+   --
+   --  Returns True if size was set correctly.
+
+
+   function render   (Self : access Item;   Text     : in String;
+                                            Length   : in Integer;
+                                            Position : in Vector_3;
+                                            Spacing  : in Vector_3;
+                                            Mode     : in renderMode) return Vector_3;
+
+   function Quad     (Self : access Item;   for_Character : in Character) return openGL.GlyphImpl.Texture.Quad_t;
+
+
+   ---------------
+   --- 'Protected'
+   --
+
+   function MakeGlyphImpl (Self : access Item;   ftGlyph : in freetype_c.FT_GlyphSlot.item) return access Glyph.item'Class;
+   --
+   --  Create an FTTextureGlyph object for the base class.
+
+
+   function gl_Texture    (Self : in     Item) return openGL.Texture.texture_Name;
+
+
+
+private
+
+   use type openGL.Texture.texture_Name;
+   package texture_name_Vectors is new ada.Containers.Vectors (Positive, openGL.Texture.texture_Name);
+
+
+   type Item is new FontImpl.item with
+      record
+         maximumGLTextureSize : aliased gl.GLsizei := 0;   -- The max texture dimension on this openGL implemetation.
+
+         textureWidth         :         gl.GLsizei := 0;   -- The min texture width  required to hold the glyphs.
+         textureHeight        :         gl.GLsizei := 0;   -- The min texture height required to hold the glyphs.
+         textureIDList        :         texture_name_Vectors.Vector;
+                                                           -- An array of texture ids.
+
+         glyphHeight          :         Integer    := 0;   -- The max height for glyphs in the current font.
+         glyphWidth           :         Integer    := 0;   -- The max width  for glyphs in the current font.
+
+         Padding              :         Natural    := 3;   -- A value to be added to the height and width to ensure that
+         numGlyphs            :         Natural;           -- glyphs don't overlap in the texture.
+         remGlyphs            :         Natural;
+
+         xOffset, yOffset     :         Integer    := 0;
+      end record;
+
+
+   procedure CalculateTextureSize (Self : in out Item);
+   --
+   --  Get the size of a block of memory required to layout the glyphs
+   --
+   --  Calculates a width and height based on the glyph sizes and the
+   --  number of glyphs. It over estimates.
+
+
+   function CreateTexture (Self : access Item) return openGL.Texture.texture_Name;
+   --
+   --  Creates a 'blank' openGL texture object.
+   --
+   --  The format is GL_ALPHA and the params are
+   --     * GL_TEXTURE_WRAP_S = GL_CLAMP
+   --     * GL_TEXTURE_WRAP_T = GL_CLAMP
+   --     * GL_TEXTURE_MAG_FILTER = GL_LINEAR
+   --     * GL_TEXTURE_MIN_FILTER = GL_LINEAR
+   --     * Note that mipmapping is NOT used
+
+
+   procedure free_Textures (Self : in out Item);
+
+end openGL.FontImpl.Texture;