Files
lace/3-mid/opengl/source/lean/buffer/opengl-buffer.ads
2025-10-22 14:11:39 +11:00

127 lines
2.7 KiB
Ada

private
with
GL.lean,
ada.unchecked_Conversion;
package openGL.Buffer
--
-- Models a buffer object.
--
is
--------------
--- Core Types
--
subtype a_Name is GL.GLuint; -- An openGL vertex buffer 'Name'.
type a_Kind is (array_Buffer, element_array_Buffer);
type Usage is (stream_Draw, static_Draw, dynamic_Draw);
-----------------
-- Buffer Object
--
type Object is abstract tagged limited private;
type View is access all Object'Class;
procedure destroy (Self : in out Object'Class);
procedure free (Self : in out View);
--------------
-- Attributes
--
function Name (Self : in Object) return Buffer.a_Name;
function Kind (Self : in Object) return Buffer.a_Kind is abstract;
function Length (Self : in Object) return Positive;
--------------
-- Operations
--
procedure enable (Self : in Object'Class);
-----------------------------------------------
-- Derived 'array' and 'element array' Classes
--
type array_Object is new Object with private;
type element_array_Object is new Object with private;
--
-- Refer to child packages, for specific buffers:
--
-- - gl.Buffer.vertex
-- - gl.Buffer.texture_coords
-- - gl.Buffer.normals
-- - gl.Buffer.indices
--
-- (TODO: pixel pack/unpack buffers)
----------
-- Errors
--
no_platform_Support : exception;
--
-- Raised by buffer 'Map' functions when OS platform does not
-- support GL Buffer objects.
private
use GL.lean;
-- Buffer Kinds
--
for a_Kind use (array_Buffer => GL_ARRAY_BUFFER,
element_array_Buffer => GL_ELEMENT_ARRAY_BUFFER);
for a_Kind'Size use gl.GLenum'Size;
function to_GL_Enum is new ada.unchecked_Conversion (a_Kind, gl.GLenum);
-- Usage
--
for Usage use (stream_Draw => GL_STREAM_DRAW,
static_Draw => GL_STATIC_DRAW,
dynamic_Draw => GL_DYNAMIC_DRAW);
for Usage'Size use GL.GLenum'Size;
function to_GL_Enum is new ada.unchecked_Conversion (Usage, gl.GLenum);
----------
-- Object
--
type Object is abstract tagged limited
record
Name : aliased Buffer.a_Name := 0;
Length : Positive;
end record;
overriding
function Kind (Self : in array_Object) return Buffer.a_Kind;
overriding
function Kind (Self : in element_array_Object) return Buffer.a_Kind;
type array_Object is new Object with null record;
type element_array_Object is new Object with null record;
-- Support
--
procedure verify_Name (Self : in out Object'Class);
end openGL.Buffer;