/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2011-2017 - Daniel De Matteis
 *  Copyright (C) 2016-2019 - Brad Parker
 *
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdint.h>
#include <stdlib.h>
#include <signal.h>

#ifdef HAVE_CONFIG_H
#include "../../config.h"
#endif

#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
#include <GL/glx.h>
#include <glsym/rglgen.h>

#ifndef GLX_SAMPLE_BUFFERS
#define GLX_SAMPLE_BUFFERS 100000
#endif

#ifndef GLX_SAMPLES
#define GLX_SAMPLES 100001
#endif

#endif

#include <string/stdstring.h>
#include <compat/strcasestr.h>
#include <X11/Xatom.h>

#include "../../configuration.h"
#include "../../frontend/frontend_driver.h"
#include "../../input/input_driver.h"
#include "../../verbosity.h"
#include "../common/gl_common.h"
#include "../common/x11_common.h"

#ifdef HAVE_XINERAMA
#include "../common/xinerama_common.h"
#endif

#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
static int      (*g_pglSwapInterval)(int);
static int      (*g_pglSwapIntervalSGI)(int);
static void     (*g_pglSwapIntervalEXT)(Display*, GLXDrawable, int);
#endif

typedef struct gfx_ctx_x_data
{
   bool use_hw_ctx;
   bool core_es;
   bool core_es_core;
   bool debug;
#ifdef HAVE_XF86VM
   bool should_reset_mode;
#endif
   bool is_fullscreen;
   bool is_double;
   bool core_hw_context_enable;
   bool adaptive_vsync;
   bool msaa_enable;

#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
   GLXWindow glx_win;
   GLXContext ctx, hw_ctx;
   GLXFBConfig fbc;
   unsigned swap_mode;
#endif

   int interval;
} gfx_ctx_x_data_t;

/* TODO/FIXME - static globals */
static unsigned g_major                       = 0;
static unsigned g_minor                       = 0;
static enum gfx_ctx_api x_api                 = GFX_CTX_NONE;
static gfx_ctx_x_data_t *current_context_data = NULL;

typedef struct Hints
{
   unsigned long flags;
   unsigned long functions;
   unsigned long decorations;
   long          inputMode;
   unsigned long status;
} Hints;

/* We use long because X11 wants 32-bit pixels for 32-bit systems and 64 for 64... */
/* ARGB*/
static const unsigned long retroarch_icon_data[] = {
   16, 16,
0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,
0x00000000,0x00000000,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xfff2f2f2,0xff333333,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xff333333,0xfff2f2f2,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xff333333,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xff333333,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xfff2f2f2,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xfff2f2f2,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,
0x00000000,0x00000000,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0xff333333,0x00000000,0x00000000,0x00000000,
0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000
};

#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
static PFNGLXCREATECONTEXTATTRIBSARBPROC glx_create_context_attribs;

static int GLXExtensionSupported(Display *dpy, const char *ext)
{
   const char *ext_string        = glXQueryExtensionsString(dpy, DefaultScreen(dpy));
   const char *client_extensions = glXGetClientString(dpy, GLX_EXTENSIONS);
   const char *pos               = strstr(ext_string, ext);
   size_t pos_ext_len            = strlen(ext);

   if (      pos
         && (pos == ext_string       || pos[-1] == ' ')
         && (pos[pos_ext_len] == ' ' || pos[pos_ext_len] == '\0')
      )
      return 1;

   pos                           = strstr(client_extensions, ext);
   pos_ext_len                   = strlen(ext);

   if (
             pos
         && (pos == ext_string       || pos[-1] == ' ')
         && (pos[pos_ext_len] == ' ' || pos[pos_ext_len] == '\0')
      )
      return 1;

   return 0;
}

static int x_log_error_handler(Display *dpy, XErrorEvent *event)
{
   char buf[1024];
   XGetErrorText(dpy, event->error_code, buf, sizeof buf);
   RARCH_WARN("[GLX]: X error message: %s, request code: %d, minor code: %d\n",
         buf, event->request_code, event->minor_code);
   return 0;
}
#endif

static int x_nul_handler(Display *dpy, XErrorEvent *event) { return 0; }

static void gfx_ctx_x_destroy_resources(gfx_ctx_x_data_t *x)
{
   x11_input_ctx_destroy();

   if (g_x11_dpy)
   {
      switch (x_api)
      {
         case GFX_CTX_OPENGL_API:
         case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
            if (x->ctx)
            {
               uint32_t video_st_flags;
               video_driver_state_t *video_st = video_state_get_ptr();

               glXSwapBuffers(g_x11_dpy, x->glx_win);
               gl_finish();
               glXMakeContextCurrent(g_x11_dpy, None, None, NULL);

               video_st_flags = video_st->flags;
               if (!(video_st_flags & VIDEO_FLAG_CACHE_CONTEXT))
               {
                  if (x->hw_ctx)
                     glXDestroyContext(g_x11_dpy, x->hw_ctx);
                  if (x->ctx)
                     glXDestroyContext(g_x11_dpy, x->ctx);

                  x->ctx    = NULL;
                  x->hw_ctx = NULL;
               }
            }

            if (g_x11_win)
            {
               if (x->glx_win)
                  glXDestroyWindow(g_x11_dpy, x->glx_win);
               x->glx_win = 0;
            }
#endif
            break;
         case GFX_CTX_NONE:
         default:
            break;
      }
   }

   if (g_x11_win && g_x11_dpy)
   {
#ifdef HAVE_XINERAMA
      /* Save last used monitor for later. */
      xinerama_save_last_used_monitor(DefaultRootWindow(g_x11_dpy));
#endif
      x11_window_destroy(false);
   }

   x11_colormap_destroy();

#ifdef HAVE_XF86VM
   if (g_x11_dpy)
   {
      if (x->should_reset_mode)
      {
         x11_exit_fullscreen(g_x11_dpy);
         x->should_reset_mode = false;
      }
   }
#endif

#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
   g_pglSwapInterval    = NULL;
   g_pglSwapIntervalSGI = NULL;
   g_pglSwapIntervalEXT = NULL;
#endif
   g_major              = 0;
   g_minor              = 0;
   x->core_es           = false;
}

static void gfx_ctx_x_destroy(void *data)
{
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;
   if (!x)
      return;

   gfx_ctx_x_destroy_resources(x);

   free(data);
}

static void gfx_ctx_x_swap_interval(void *data, int interval)
{
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;

#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
   x->interval = interval;

   if (x->swap_mode)
   {
      if (g_pglSwapInterval)
      {
         if (g_pglSwapInterval(x->interval) != 0)
            RARCH_WARN("[GLX]: glXSwapInterval(%i) failed.\n", x->interval);
      }
      else if (g_pglSwapIntervalEXT)
         g_pglSwapIntervalEXT(g_x11_dpy, x->glx_win, x->interval);
      else if (g_pglSwapIntervalSGI)
      {
         if (g_pglSwapIntervalSGI(x->interval) != 0)
            RARCH_WARN("[GLX]: glXSwapIntervalSGI(%i) failed.\n", x->interval);
      }
   }
   else
   {
      if (g_pglSwapIntervalEXT)
         g_pglSwapIntervalEXT(g_x11_dpy, x->glx_win, x->interval);
      else if (g_pglSwapInterval)
      {
         if (g_pglSwapInterval(x->interval) != 0)
            RARCH_WARN("[GLX]: glXSwapInterval(%i) failed.\n", x->interval);
      }
      else if (g_pglSwapIntervalSGI)
      {
         if (g_pglSwapIntervalSGI(x->interval) != 0)
            RARCH_WARN("[GLX]: glXSwapIntervalSGI(%i) failed.\n", x->interval);
      }
   }
#endif
}

static void gfx_ctx_x_swap_buffers(void *data)
{
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;
   if (x->is_double)
      glXSwapBuffers(g_x11_dpy, x->glx_win);
#endif
}

static bool gfx_ctx_x_set_resize(void *data,
      unsigned width, unsigned height)
{
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;

   if (!x)
      return false;

   /*
    * X11 loses focus on monitor/resolution swap and exits fullscreen.
    * Set window on top again to maintain both fullscreen and resolution.
    */
   if (x->is_fullscreen)
   {
      XMapRaised(g_x11_dpy, g_x11_win);
      RARCH_LOG("[GLX]: Resized fullscreen resolution to %dx%d.\n", width, height);
   }

   return true;
}

static void *gfx_ctx_x_init(void *data)
{
   int nelements           = 0;
   int major               = 0;
   int minor               = 0;
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
   static const int visual_attribs[] = {
      GLX_X_RENDERABLE     , True,
      GLX_DRAWABLE_TYPE    , GLX_WINDOW_BIT,
      GLX_RENDER_TYPE      , GLX_RGBA_BIT,
      GLX_DOUBLEBUFFER     , True,
      GLX_RED_SIZE         , 8,
      GLX_GREEN_SIZE       , 8,
      GLX_BLUE_SIZE        , 8,
      GLX_ALPHA_SIZE       , 8,
      GLX_DEPTH_SIZE       , 0,
      GLX_STENCIL_SIZE     , 0,
      GLX_SAMPLE_BUFFERS   , 0,
      GLX_SAMPLES          , 0,
      None
   };
   GLXFBConfig *fbcs       = NULL;
#endif
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)
      calloc(1, sizeof(gfx_ctx_x_data_t));
#ifndef GL_DEBUG
   struct retro_hw_render_callback *hwr =
      video_driver_get_hw_context();
#endif

   if (!x)
      return NULL;

   current_context_data = x;

   XInitThreads();

   if (!x11_connect())
      goto error;

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGLES) || defined(HAVE_OPENGL_CORE)
         glXQueryVersion(g_x11_dpy, &major, &minor);

         /* GLX 1.3+ minimum required. */
         if ((major * 1000 + minor) < 1003)
            goto error;

         glx_create_context_attribs = (PFNGLXCREATECONTEXTATTRIBSARBPROC)
            glXGetProcAddress((const GLubyte*)"glXCreateContextAttribsARB");

#ifdef GL_DEBUG
         x->debug          = true;
#else
         x->debug          = hwr->debug_context;
#endif

         /* Have to use ContextAttribs */
#ifdef HAVE_OPENGLES2
         x->core_es        = true;
         x->core_es_core   = true;
#else
         x->core_es        = (g_major * 1000 + g_minor) >= 3001;
         x->core_es_core   = (g_major * 1000 + g_minor) >= 3002;
#endif

         if ((x->core_es || x->debug) && !glx_create_context_attribs)
            goto error;

         fbcs = glXChooseFBConfig(g_x11_dpy, DefaultScreen(g_x11_dpy),
               visual_attribs, &nelements);

         if (!fbcs)
            goto error;

         if (!nelements)
         {
            XFree(fbcs);
            goto error;
         }

         x->fbc = fbcs[0];
         XFree(fbcs);
#endif
         break;
      case GFX_CTX_NONE:
      default:
         break;
   }

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         if (GLXExtensionSupported(g_x11_dpy, "GLX_EXT_swap_control_tear"))
         {
            RARCH_LOG("[GLX]: GLX_EXT_swap_control_tear supported.\n");
            x->adaptive_vsync = true;
         }

         if (     GLXExtensionSupported(g_x11_dpy, "GLX_OML_sync_control")
               && GLXExtensionSupported(g_x11_dpy, "GLX_MESA_swap_control")
            )
            x->swap_mode         = 1;
#endif
         break;
      default:
         break;
   }

   return x;

error:
   if (x)
   {
      gfx_ctx_x_destroy_resources(x);
      free(x);
   }
   g_x11_screen = 0;

   return NULL;
}

static bool gfx_ctx_x_set_video_mode(void *data,
      unsigned width, unsigned height,
      bool fullscreen)
{
   XEvent event;
#ifdef HAVE_XF86VM
   bool true_full            = false;
#endif
   int val                   = 0;
   int x_off                 = 0;
   int y_off                 = 0;
   XVisualInfo *vi           = NULL;
   XSetWindowAttributes swa  = {0};
   int (*old_handler)(Display*, XErrorEvent*) = NULL;
   gfx_ctx_x_data_t *x       = (gfx_ctx_x_data_t*)data;
   Atom net_wm_icon          = XInternAtom(g_x11_dpy, "_NET_WM_ICON", False);
   Atom cardinal             = XInternAtom(g_x11_dpy, "CARDINAL", False);
   settings_t *settings      = config_get_ptr();
   unsigned opacity          = settings->uints.video_window_opacity
      * ((unsigned)-1 / 100.0);
   bool disable_composition  = settings->bools.video_disable_composition;
   bool show_decorations     = settings->bools.video_window_show_decorations;
   bool windowed_full        = settings->bools.video_windowed_fullscreen;
   unsigned video_monitor_index = settings->uints.video_monitor_index;

   frontend_driver_install_signal_handler();

   if (!x)
      return false;

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         vi = glXGetVisualFromFBConfig(g_x11_dpy, x->fbc);
         if (!vi)
            goto error;
#endif
         break;

      case GFX_CTX_NONE:
      default:
      {
         XVisualInfo vi_template;
         /* For default case, just try to obtain a visual from template. */
         int nvisuals = 0;

         memset(&vi_template, 0, sizeof(vi_template));
         vi_template.screen = DefaultScreen(g_x11_dpy);
         vi = XGetVisualInfo(g_x11_dpy, VisualScreenMask, &vi_template, &nvisuals);
         if (!vi || nvisuals < 1)
            goto error;
      }
      break;
   }

   swa.colormap = g_x11_cmap = XCreateColormap(g_x11_dpy,
         RootWindow(g_x11_dpy, vi->screen), vi->visual, AllocNone);
   swa.event_mask = StructureNotifyMask | KeyPressMask | KeyReleaseMask |
      LeaveWindowMask | EnterWindowMask |
      ButtonReleaseMask | ButtonPressMask;
   swa.override_redirect = False;

   x->is_fullscreen = fullscreen;

#ifdef HAVE_XF86VM
   if (fullscreen && !windowed_full)
   {
      if (x11_enter_fullscreen(g_x11_dpy, width, height))
      {
         char *wm_name        = x11_get_wm_name(g_x11_dpy);
         x->should_reset_mode = true;
         true_full            = true;

         if (wm_name)
         {
            RARCH_LOG("[GLX]: Window manager is %s.\n", wm_name);
            if (strcasestr(wm_name, "xfwm"))
            {
               RARCH_LOG("[GLX]: Using override-redirect workaround.\n");
               swa.override_redirect = True;
            }
            free(wm_name);
         }

         if (!x11_has_net_wm_fullscreen(g_x11_dpy))
            swa.override_redirect = True;
      }
      else
         RARCH_ERR("[GLX]: Entering true fullscreen failed. Will attempt windowed mode.\n");
   }
#endif

   if (video_monitor_index)
      g_x11_screen = video_monitor_index - 1;

#ifdef HAVE_XINERAMA
   if (fullscreen || g_x11_screen != 0)
   {
      unsigned new_width  = width;
      unsigned new_height = height;

      if (xinerama_get_coord(g_x11_dpy, g_x11_screen,
               &x_off, &y_off, &new_width, &new_height))
         RARCH_LOG("[GLX]: Using Xinerama on screen #%u.\n", g_x11_screen);
      else
         RARCH_LOG("[GLX]: Xinerama is not active on screen.\n");

      if (fullscreen)
      {
         width  = new_width;
         height = new_height;
      }
   }
#endif

   RARCH_LOG("[GLX]: X = %d, Y = %d, W = %u, H = %u.\n",
         x_off, y_off, width, height);

   g_x11_win = XCreateWindow(g_x11_dpy, RootWindow(g_x11_dpy, vi->screen),
         x_off, y_off, width, height, 0,
         vi->depth, InputOutput, vi->visual,
         CWBorderPixel | CWColormap | CWEventMask | CWOverrideRedirect,
         &swa);
   XSetWindowBackground(g_x11_dpy, g_x11_win, 0);

   XChangeProperty(g_x11_dpy, g_x11_win, net_wm_icon, cardinal, 32, PropModeReplace, (const unsigned char*)retroarch_icon_data, sizeof(retroarch_icon_data) / sizeof(*retroarch_icon_data));

   if (fullscreen && disable_composition)
   {
      uint32_t                value = 1;
      Atom net_wm_bypass_compositor = XInternAtom(g_x11_dpy, "_NET_WM_BYPASS_COMPOSITOR", False);

      RARCH_LOG("[GLX]: Requesting compositor bypass.\n");
      XChangeProperty(g_x11_dpy, g_x11_win, net_wm_bypass_compositor, cardinal, 32, PropModeReplace, (const unsigned char*)&value, 1);
   }

   if (opacity < (unsigned)-1)
   {
      Atom net_wm_opacity = XInternAtom(g_x11_dpy, "_NET_WM_WINDOW_OPACITY", False);
      XChangeProperty(g_x11_dpy, g_x11_win, net_wm_opacity, cardinal, 32, PropModeReplace, (const unsigned char*)&opacity, 1);
   }

   if (!show_decorations)
   {
      /* We could have just set _NET_WM_WINDOW_TYPE_DOCK instead,
       * but that removes the window from any taskbar/panel,
       * so we are forced to use the old motif hints method. */
      Hints hints;
      Atom property     = XInternAtom(g_x11_dpy, "_MOTIF_WM_HINTS", False);

      hints.flags       = 2;
      hints.decorations = 0;

      XChangeProperty(g_x11_dpy, g_x11_win, property, property, 32, PropModeReplace, (const unsigned char*)&hints, 5);
   }

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         x->glx_win = glXCreateWindow(g_x11_dpy, x->fbc, g_x11_win, 0);
#endif
         break;

      case GFX_CTX_NONE:
      default:
         break;
   }

   x11_set_window_attr(g_x11_dpy, g_x11_win);
   x11_update_title(NULL);

   if (fullscreen)
      x11_show_mouse(data, false);

#ifdef HAVE_XF86VM
   if (true_full)
   {
      RARCH_LOG("[GLX]: Using true fullscreen.\n");
      XMapRaised(g_x11_dpy, g_x11_win);
      x11_set_net_wm_fullscreen(g_x11_dpy, g_x11_win);
   }
   else
#endif
   if (fullscreen)
   {
      /* We attempted true fullscreen, but failed.
       * Attempt using windowed fullscreen. */

      XMapRaised(g_x11_dpy, g_x11_win);
      RARCH_LOG("[GLX]: Using windowed fullscreen.\n");

      /* We have to move the window to the screen we want
       * to go fullscreen on first.
       * x_off and y_off usually get ignored in XCreateWindow().
       */
      x11_move_window(g_x11_dpy, g_x11_win, x_off, y_off, width, height);
      x11_set_net_wm_fullscreen(g_x11_dpy, g_x11_win);
   }
   else
   {
      XMapWindow(g_x11_dpy, g_x11_win);
      /* If we want to map the window on a different screen,
       * we'll have to do it by force.
       * Otherwise, we should try to let the window manager sort it out.
       * x_off and y_off usually get ignored in XCreateWindow(). */
      if (g_x11_screen)
         x11_move_window(g_x11_dpy, g_x11_win, x_off, y_off, width, height);
   }

   x11_event_queue_check(&event);

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         if (!x->ctx)
         {
            if (x->core_es || x->debug)
            {
               int attribs[16] = {0};
               int *aptr = attribs;

               if (x->core_es)
               {
                  *aptr++ = GLX_CONTEXT_MAJOR_VERSION_ARB;
                  *aptr++ = g_major;
                  *aptr++ = GLX_CONTEXT_MINOR_VERSION_ARB;
                  *aptr++ = g_minor;

                  if (x->core_es_core)
                  {
                     /* Technically, we don't have core/compat until 3.2.
                      * Version 3.1 is either compat or not depending on
                      * GL_ARB_compatibility.
                      */
                     *aptr++ = GLX_CONTEXT_PROFILE_MASK_ARB;
#ifdef HAVE_OPENGLES2
                     *aptr++ = GLX_CONTEXT_ES_PROFILE_BIT_EXT;
#else
                     *aptr++ = GLX_CONTEXT_CORE_PROFILE_BIT_ARB;
#endif
                  }
               }

               if (x->debug)
               {
                  *aptr++ = GLX_CONTEXT_FLAGS_ARB;
                  *aptr++ = GLX_CONTEXT_DEBUG_BIT_ARB;
               }

               *aptr = None;

               old_handler = XSetErrorHandler(x_log_error_handler);

               /* In order to support the core info "required_hw_api" field correctly, we should try to init the highest available
                * version GL context possible. This means trying successively lower versions until it works, because GL has
                * no facility for determining the highest possible supported version.
                */
               {
                  int i;
                  int (*versions)[2];
                  int gl_versions[][2]   = {{4, 6}, {4, 5}, {4, 4}, {4, 3}, {4, 2}, {4, 1}, {4, 0}, {3, 3}, {3, 2}, {3, 1}, {3, 0}};
#ifdef HAVE_OPENGLES3
                  int gles_versions[][2] = {{3, 2}, {3, 1}, {3, 0}, {2, 0}, {1, 1}, {1, 0}};
#else
                  int gles_versions[][2] = {{2, 0}, {1, 1}, {1, 0}};
#endif
                  int gl_version_rows    = ARRAY_SIZE(gl_versions);
                  int gles_version_rows  = ARRAY_SIZE(gles_versions);
                  int version_rows       = 0;

                  if (x_api == GFX_CTX_OPENGL_API)
                  {
                     versions     = gl_versions;
                     version_rows = gl_version_rows;
                  }
                  else
                  {
                     versions     = gles_versions;
                     version_rows = gles_version_rows;
                  }

                  /* Mesa/X currently crashes when an unsupported version is
                   * requested. Since Mesa always seems to return a context
                   * of the highest compatible version, we start with the
                   * requested version first.
                   * The following code can hopefully be removed in the future:
                   */
                  RARCH_LOG("[GLX]: Creating context for requested version %u.%u.\n", g_major, g_minor);
                  x->ctx = glx_create_context_attribs(g_x11_dpy,
                        x->fbc, NULL, True, attribs);

                  if (x->ctx)
                  {
                     const char *version;

                     if (x->use_hw_ctx)
                     {
                        RARCH_LOG("[GLX]: Creating shared HW context.\n");
                        x->hw_ctx = glx_create_context_attribs(g_x11_dpy,
                              x->fbc, x->ctx, True, attribs);

                        if (!x->hw_ctx)
                           RARCH_ERR("[GLX]: Failed to create new shared context.\n");
                     }

                     glXMakeContextCurrent(g_x11_dpy,
                           x->glx_win, x->glx_win, x->ctx);

                     version = (const char*)glGetString(GL_VERSION);
                     if (strstr(version, " Mesa ") || !x->core_es)
                     {
                        /* we are done, break switch case */
                        XSetErrorHandler(old_handler);
                        break;
                     }

                     glXMakeContextCurrent(g_x11_dpy, None, None, NULL);
                     glXDestroyContext(g_x11_dpy, x->ctx);

                     RARCH_LOG("[GLX]: Not running Mesa, trying higher versions...\n");
                  }
                  else
                  {
                     RARCH_ERR("[GLX]: Failed to create new context.\n");
                     goto error;
                  }
                  /* end of Mesa workaround / code to be removed */

                  /* only try higher versions when x->core_es is true */
                  if (!x->core_es)
                     version_rows = 1;

                  /* try versions from highest down to requested version */
                  for (i = 0; i < version_rows; i++)
                  {
                     if (x->core_es)
                     {
                        attribs[1] = versions[i][0];
                        attribs[3] = versions[i][1];
                        RARCH_LOG("[GLX]: Creating context for version %d.%d.\n", versions[i][0], versions[i][1]);
                     }
                     else
                        RARCH_LOG("[GLX]: Creating context for version %u.%u.\n", g_major, g_minor);

                     x->ctx = glx_create_context_attribs(g_x11_dpy,
                           x->fbc, NULL, True, attribs);

                     if (x->ctx)
                     {
                        if (x->use_hw_ctx)
                        {
                           RARCH_LOG("[GLX]: Creating shared HW context.\n");
                           x->hw_ctx = glx_create_context_attribs(g_x11_dpy,
                                 x->fbc, x->ctx, True, attribs);

                           if (!x->hw_ctx)
                              RARCH_ERR("[GLX]: Failed to create new shared context.\n");
                        }

                        break;
                     }
                     else if (versions[i][0] == (int)g_major && versions[i][1] == (int)g_minor)
                     {
                        /* The requested version was tried and is not supported, go ahead and fail since everything else will be lower than that. */
                        break;
                     }
                  }
               }

               XSetErrorHandler(old_handler);
            }
            else
            {
               x->ctx = glXCreateNewContext(g_x11_dpy, x->fbc,
                     GLX_RGBA_TYPE, 0, True);

               if (x->use_hw_ctx)
               {
                  RARCH_LOG("[GLX]: Creating shared HW context.\n");
                  x->hw_ctx = glXCreateNewContext(g_x11_dpy, x->fbc,
                        GLX_RGBA_TYPE, x->ctx, True);

                  if (!x->hw_ctx)
                     RARCH_ERR("[GLX]: Failed to create new shared context.\n");
               }
            }

            if (!x->ctx)
            {
               RARCH_ERR("[GLX]: Failed to create new context.\n");
               goto error;
            }
         }
         else
         {
            video_state_get_ptr()->flags |= VIDEO_FLAG_CACHE_CONTEXT_ACK;
            RARCH_LOG("[GLX]: Using cached GL context.\n");
         }

         glXMakeContextCurrent(g_x11_dpy,
               x->glx_win, x->glx_win, x->ctx);
#endif
         break;
      case GFX_CTX_NONE:
      default:
         break;
   }

   XSync(g_x11_dpy, False);

   x11_install_quit_atom();

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         glXGetConfig(g_x11_dpy, vi, GLX_DOUBLEBUFFER, &val);
         x->is_double = val;

         if (x->is_double)
         {
            const char *swap_func = NULL;

            g_pglSwapIntervalEXT = (void (*)(Display*, GLXDrawable, int))
               glXGetProcAddress((const GLubyte*)"glXSwapIntervalEXT");
            g_pglSwapIntervalSGI = (int (*)(int))
               glXGetProcAddress((const GLubyte*)"glXSwapIntervalSGI");
            g_pglSwapInterval    = (int (*)(int))
               glXGetProcAddress((const GLubyte*)"glXSwapIntervalMESA");

            if (g_pglSwapIntervalEXT)
               swap_func = "glXSwapIntervalEXT";
            else if (g_pglSwapInterval)
               swap_func = "glXSwapIntervalMESA";
            else if (g_pglSwapIntervalSGI)
               swap_func = "glXSwapIntervalSGI";

            if (!g_pglSwapInterval && !g_pglSwapIntervalEXT && !g_pglSwapIntervalSGI)
               RARCH_WARN("[GLX]: Cannot find swap interval call.\n");
            else
               RARCH_LOG("[GLX]: Found swap function: %s.\n", swap_func);
         }
         else
            RARCH_WARN("[GLX]: Context is not double buffered!.\n");
#endif
         break;

      case GFX_CTX_NONE:
      default:
         break;
   }

   gfx_ctx_x_swap_interval(data, x->interval);

   /* This can blow up on some drivers.
    * It's not fatal, so override errors for this call. */
   old_handler = XSetErrorHandler(x_nul_handler);
   XSetInputFocus(g_x11_dpy, g_x11_win, RevertToNone, CurrentTime);
   XSync(g_x11_dpy, False);
   XSetErrorHandler(old_handler);

   XFree(vi);
   vi = NULL;

#ifdef HAVE_XF86VM
   if (!x11_input_ctx_new(true_full))
      goto error;
#else
   if (!x11_input_ctx_new(false))
      goto error;
#endif

   return true;

error:
   if (vi)
      XFree(vi);

   gfx_ctx_x_destroy_resources(x);

   if (x)
      free(x);
   g_x11_screen = 0;

   return false;
}

static void gfx_ctx_x_input_driver(void *data,
      const char *joypad_name,
      input_driver_t **input, void **input_data)
{
   void *x_input            = NULL;
#ifdef HAVE_UDEV
   settings_t *settings     = config_get_ptr();
   const char *input_driver = settings->arrays.input_driver;

   if (string_is_equal(input_driver, "udev"))
   {
      *input_data = input_driver_init_wrap(&input_udev, joypad_name);
      if (*input_data)
      {
         *input = &input_udev;
         return;
      }
   }
#endif

   x_input      = input_driver_init_wrap(&input_x, joypad_name);
   *input       = x_input ? &input_x : NULL;
   *input_data  = x_input;
}

static gfx_ctx_proc_t gfx_ctx_x_get_proc_address(const char *symbol)
{
   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         return glXGetProcAddress((const GLubyte*)symbol);
#else
         break;
#endif
      case GFX_CTX_NONE:
      default:
         break;
   }

   return NULL;
}

static enum gfx_ctx_api gfx_ctx_x_get_api(void *data)
{
   return x_api;
}

static bool gfx_ctx_x_bind_api(void *data, enum gfx_ctx_api api,
      unsigned major, unsigned minor)
{
   g_major = major;
   g_minor = minor;
   x_api   = api;

   switch (api)
   {
      case GFX_CTX_OPENGL_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         return true;
#else
         break;
#endif
      case GFX_CTX_OPENGL_ES_API:
#ifdef HAVE_OPENGLES2
         {
            Display     *dpy = XOpenDisplay(NULL);
            const char *exts = glXQueryExtensionsString(dpy, DefaultScreen(dpy));
            bool ret         = exts && strstr(exts,
                  "GLX_EXT_create_context_es2_profile");
            XCloseDisplay(dpy);
            if (ret && g_major < 3)
            {
               g_major = 2; /* ES 2.0. */
               g_minor = 0;
            }
            return ret;
         }
#else
         break;
#endif
      case GFX_CTX_NONE:
      default:
         break;
   }

   return false;
}

static void gfx_ctx_x_bind_hw_render(void *data, bool enable)
{
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;

   if (!x)
      return;

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         x->use_hw_ctx = enable;
         if (!g_x11_dpy || !x->glx_win)
            return;
         glXMakeContextCurrent(g_x11_dpy, x->glx_win,
               x->glx_win, enable ? x->hw_ctx : x->ctx);
#endif
         break;

      case GFX_CTX_NONE:
      default:
         break;
   }
}

static uint32_t gfx_ctx_x_get_flags(void *data)
{
   uint32_t      flags = 0;
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
         if (x->adaptive_vsync)
            BIT32_SET(flags, GFX_CTX_FLAGS_ADAPTIVE_VSYNC);

         if (x->core_hw_context_enable || x->core_es)
            BIT32_SET(flags, GFX_CTX_FLAGS_GL_CORE_CONTEXT);

         if (x->msaa_enable)
            BIT32_SET(flags, GFX_CTX_FLAGS_MULTISAMPLING);

         if (string_is_equal(video_driver_get_ident(), "gl1")) { }
         else if (string_is_equal(video_driver_get_ident(), "glcore"))
         {
#if defined(HAVE_SLANG) && defined(HAVE_SPIRV_CROSS)
            BIT32_SET(flags, GFX_CTX_FLAGS_SHADERS_SLANG);
#endif
         }
         else
         {
#ifdef HAVE_CG
            if (!(x->core_hw_context_enable || x->core_es))
               BIT32_SET(flags, GFX_CTX_FLAGS_SHADERS_CG);
#endif
#ifdef HAVE_GLSL
            BIT32_SET(flags, GFX_CTX_FLAGS_SHADERS_GLSL);
#endif
         }
         break;
      case GFX_CTX_NONE:
      default:
         break;
   }

   return flags;
}

static void gfx_ctx_x_set_flags(void *data, uint32_t flags)
{
   gfx_ctx_x_data_t *x = (gfx_ctx_x_data_t*)data;

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
         if (BIT32_GET(flags, GFX_CTX_FLAGS_ADAPTIVE_VSYNC))
               x->adaptive_vsync = true;
         if (BIT32_GET(flags, GFX_CTX_FLAGS_GL_CORE_CONTEXT))
            x->core_hw_context_enable = true;
         if (BIT32_GET(flags, GFX_CTX_FLAGS_MULTISAMPLING))
            x->msaa_enable = true;
         break;
      case GFX_CTX_NONE:
      default:
         break;
   }
}

static void gfx_ctx_x_make_current(bool release)
{
   if (!current_context_data)
      return;

   switch (x_api)
   {
      case GFX_CTX_OPENGL_API:
      case GFX_CTX_OPENGL_ES_API:
#if defined(HAVE_OPENGL) || defined(HAVE_OPENGL1) || defined(HAVE_OPENGL_CORE)
         if (release)
            glXMakeContextCurrent(g_x11_dpy, None, None, NULL);
         else
            glXMakeContextCurrent(g_x11_dpy,
                  current_context_data->glx_win,
                  current_context_data->glx_win, current_context_data->ctx);
#endif
         break;

      case GFX_CTX_NONE:
      default:
         break;
   }
}

const gfx_ctx_driver_t gfx_ctx_x = {
   gfx_ctx_x_init,
   gfx_ctx_x_destroy,
   gfx_ctx_x_get_api,
   gfx_ctx_x_bind_api,
   gfx_ctx_x_swap_interval,
   gfx_ctx_x_set_video_mode,
   x11_get_video_size,
#ifdef HAVE_XF86VM
   x11_get_refresh_rate,
#else
   NULL,
#endif
   NULL, /* get_video_output_size */
   NULL, /* get_video_output_prev */
   NULL, /* get_video_output_next */
   x11_get_metrics,
   NULL,
   x11_update_title,
   x11_check_window,
   gfx_ctx_x_set_resize,
   x11_has_focus,
   x11_suspend_screensaver,
   true, /* has_windowed */
   gfx_ctx_x_swap_buffers,
   gfx_ctx_x_input_driver,
   gfx_ctx_x_get_proc_address,
   NULL,
   NULL,
   x11_show_mouse,
   "x",
   gfx_ctx_x_get_flags,
   gfx_ctx_x_set_flags,

   gfx_ctx_x_bind_hw_render,
   NULL,
   gfx_ctx_x_make_current
};
