/* GDK - The GIMP Drawing Kit
 *
 * gdkglcontextprivate.h: GL context abstraction
 *
 * Copyright © 2014  Emmanuele Bassi
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "gdkglcontext.h"
#include "gdkdrawcontextprivate.h"

G_BEGIN_DECLS

/* Version requirements for EGL contexts.
 *
 * If you add support for EGL to your backend, please require this.
 */
#define GDK_EGL_MIN_VERSION_MAJOR (1)
#define GDK_EGL_MIN_VERSION_MINOR (4)

/* Minimum OpenGL versions supported by GTK.
 * Backends should make sure to never create a context of a previous version.
 *
 * The macros refer to OpenGL; OpenGL with OPENGL_COMPATIBILITY_PROFILE_BIT as
 * OPENGL_PROFILE_MASK; OpenGL ES; and OpenGL ES win32 Angle implementation,
 * respectively
 */
#define GDK_GL_MIN_GL_VERSION_MAJOR (3)
#define GDK_GL_MIN_GL_VERSION_MINOR (2)
#define GDK_GL_MIN_GL_LEGACY_VERSION_MAJOR (3)
#define GDK_GL_MIN_GL_LEGACY_VERSION_MINOR (0)
#define GDK_GL_MIN_GLES_VERSION_MAJOR (2)
#define GDK_GL_MIN_GLES_VERSION_MINOR (0)
#define GDK_GL_MIN_GLES_WIN32_ANGLE_VERSION_MAJOR (3)
#define GDK_GL_MIN_GLES_WIN32_ANGLE_VERSION_MINOR (0)

typedef enum {
  GDK_GL_NONE = 0,
  GDK_GL_EGL,
  GDK_GL_GLX,
  GDK_GL_WGL,
  GDK_GL_CGL
} GdkGLBackend;

#define GDK_GL_CONTEXT_CLASS(klass)	(G_TYPE_CHECK_CLASS_CAST ((klass), GDK_TYPE_GL_CONTEXT, GdkGLContextClass))
#define GDK_IS_GL_CONTEXT_CLASS(klass)	(G_TYPE_CHECK_CLASS_TYPE ((klass), GDK_TYPE_GL_CONTEXT))
#define GDK_GL_CONTEXT_GET_CLASS(obj)	(G_TYPE_INSTANCE_GET_CLASS ((obj), GDK_TYPE_GL_CONTEXT, GdkGLContextClass))

typedef struct _GdkGLContextClass       GdkGLContextClass;

struct _GdkGLContext
{
  GdkDrawContext parent_instance;

  /* We store the old drawn areas to support buffer-age optimizations */
  cairo_region_t *old_updated_area[2];
};

struct _GdkGLContextClass
{
  GdkDrawContextClass parent_class;

  GdkGLBackend        backend_type;

  GdkGLAPI              (* realize)                             (GdkGLContext          *context,
                                                                 GError               **error);

  gboolean              (* make_current)                        (GdkGLContext          *context,
                                                                 gboolean               surfaceless);
  gboolean              (* clear_current)                       (GdkGLContext          *context);
  gboolean              (* is_current)                          (GdkGLContext          *context);
  cairo_region_t *      (* get_damage)                          (GdkGLContext          *context);

  gboolean              (* is_shared)                           (GdkGLContext          *self,
                                                                 GdkGLContext          *other);

  guint                 (* get_default_framebuffer)             (GdkGLContext          *self);
};

typedef struct {
  guint program;
  guint position_location;
  guint uv_location;
  guint map_location;
  guint flip_location;
} GdkGLContextProgram;

typedef struct {
  guint vertex_array_object;
  guint tmp_framebuffer;
  guint tmp_vertex_buffer;

  GdkGLContextProgram texture_2d_quad_program;
  GdkGLContextProgram texture_rect_quad_program;

  GdkGLContextProgram *current_program;

  guint is_legacy : 1;
  guint use_es : 1;
} GdkGLContextPaintData;

gboolean                gdk_gl_backend_can_be_used              (GdkGLBackend     backend_type,
                                                                 GError         **error);
void                    gdk_gl_backend_use                      (GdkGLBackend     backend_type);

void                    gdk_gl_context_clear_current_if_surface (GdkSurface      *surface);

GdkGLContext *          gdk_gl_context_new                      (GdkDisplay      *display,
                                                                 GdkSurface      *surface);

gboolean                gdk_gl_context_is_api_allowed           (GdkGLContext    *self,
                                                                 GdkGLAPI         api,
                                                                 GError         **error);
void                    gdk_gl_context_set_is_legacy            (GdkGLContext    *context,
                                                                 gboolean         is_legacy);

gboolean                gdk_gl_context_check_version            (GdkGLContext    *context,
                                                                 int              required_gl_major,
                                                                 int              required_gl_minor,
                                                                 int              required_gles_major,
                                                                 int              required_gles_minor);
void                    gdk_gl_context_get_clipped_version      (GdkGLContext    *context,
                                                                 int              min_major,
                                                                 int              min_minor,
                                                                 int             *major,
                                                                 int             *minor);
void                    gdk_gl_context_get_matching_version     (GdkGLAPI         api,
                                                                 gboolean         legacy,
                                                                 gboolean         win32_libangle,
                                                                 int             *major,
                                                                 int             *minor);

gboolean                gdk_gl_context_has_unpack_subimage      (GdkGLContext    *context);
void                    gdk_gl_context_push_debug_group         (GdkGLContext    *context,
                                                                 const char      *message);
void                    gdk_gl_context_push_debug_group_printf  (GdkGLContext    *context,
                                                                 const char      *format,
                                                                 ...)  G_GNUC_PRINTF (2, 3);
void                    gdk_gl_context_pop_debug_group          (GdkGLContext    *context);
void                    gdk_gl_context_label_object             (GdkGLContext    *context,
                                                                 guint            identifier,
                                                                 guint            name,
                                                                 const char      *label);
void                    gdk_gl_context_label_object_printf      (GdkGLContext    *context,
                                                                 guint            identifier,
                                                                 guint            name,
                                                                 const char      *format,
                                                                ...)  G_GNUC_PRINTF (4, 5);

gboolean                gdk_gl_context_has_debug                (GdkGLContext    *self) G_GNUC_PURE;

gboolean                gdk_gl_context_use_es_bgra              (GdkGLContext    *context);

gboolean                gdk_gl_context_has_vertex_half_float    (GdkGLContext    *self) G_GNUC_PURE;

G_END_DECLS