Add initial prototype.

3-mid/opengl/source/lean/shader/opengl-attribute.adb

@@ -0,0 +1,115 @@
+with
+     openGL.Tasks,
+     GL.lean,
+     System,
+     ada.unchecked_Conversion;
+
+package body openGL.Attribute
+is
+   use GL.lean;
+
+   ---------
+   --  Forge
+   --
+
+   procedure define  (Self : in out Item)
+   is
+   begin
+      null;
+   end define;
+
+
+   procedure destroy (Self : in out Item)
+   is
+   begin
+      null;
+   end destroy;
+
+
+   package body Forge
+   is
+      function to_Attribute (Name        : in String;
+                             gl_Location : in gl.GLuint;
+                             Size        : in gl.GLint;
+                             data_Kind   : in Attribute.data_Kind;
+                             Stride      : in Natural;
+                             Offset      : in storage_Offset;
+                             Normalized  : in Boolean) return Item
+      is
+      begin
+         return (Name          => new String'(Name),
+                 Location      => gl_Location,
+                 Size          => Size,
+                 data_Kind     => data_Kind,
+                 vertex_Stride => gl.GLint (Stride),
+                 Offset        => Offset,
+                 Normalized    => Boolean'Pos (Normalized));
+      end to_Attribute;
+
+
+      function new_Attribute (Name        : in String;
+                              gl_Location : in gl.GLuint;
+                              Size        : in gl.GLint;
+                              data_Kind   : in Attribute.data_Kind;
+                              Stride      : in Natural;
+                              Offset      : in Storage_Offset;
+                              Normalized  : in Boolean) return View
+      is
+      begin
+         return new Item' (to_Attribute (Name,
+                                         gl_Location,
+                                         Size,
+                                         data_Kind,
+                                         Stride,
+                                         Offset,
+                                         Normalized));
+      end new_Attribute;
+
+   end Forge;
+
+
+   --------------
+   --  Attributes
+   --
+
+   function Name (Self : in Item'Class) return String
+   is
+   begin
+      return Self.Name.all;
+   end Name;
+
+
+   function gl_Location (Self : in Item'Class) return gl.GLuint
+   is
+   begin
+      return Self.Location;
+   end gl_Location;
+
+
+   --------------
+   --  Operations
+   --
+
+   procedure enable (Self : in Item)
+   is
+      use GL,
+          system.Storage_Elements;
+
+      type GLvoid_access is access all GLvoid;
+
+      function to_GL is new ada.unchecked_Conversion (attribute.data_Kind, gl.GLenum);          -- TODO: Address different sizes warning.
+      function to_GL is new ada.unchecked_Conversion (storage_Offset,      GLvoid_access);
+   begin
+      Tasks.check;
+
+      glEnableVertexAttribArray (Index      => Self.gl_Location);
+      glVertexAttribPointer     (Index      => Self.gl_Location,
+                                 Size       => Self.Size,
+                                 the_Type   => to_GL (Self.data_Kind),
+                                 Normalized => Self.Normalized,
+                                 Stride     => Self.vertex_Stride,
+                                 Ptr        => to_GL (Self.Offset));
+   end enable;
+
+
+end openGL.Attribute;