[gtk/wip/otte/gleanup: 4/9] x11: Store the GLX drawable in the surface

[Benjamin Otte <otte src gnome org>]

commit 7fc5d029a6f4787d29dd54f6ddf0436cb8dc3019
Author: Benjamin Otte <otte redhat com>
Date:   Tue Jun 29 23:45:50 2021 +0200

    x11: Store the GLX drawable in the surface
    
    Also, stop using a dummy window for unattached GL contexts and instead
    use the display's leader surface.
    
    Again, this mirrors EGL.

 gdk/x11/gdkglcontext-glx.c | 111 ++++++++++++++++++---------------------------
 gdk/x11/gdkglcontext-x11.h |   1 +
 gdk/x11/gdksurface-x11.c   |   1 +
 gdk/x11/gdksurface-x11.h   |   1 +
 4 files changed, 47 insertions(+), 67 deletions(-)
---
diff --git a/gdk/x11/gdkglcontext-glx.c b/gdk/x11/gdkglcontext-glx.c
index ad08c1fcb3..5d8708ab91 100644
--- a/gdk/x11/gdkglcontext-glx.c
+++ b/gdk/x11/gdkglcontext-glx.c
@@ -35,8 +35,6 @@ struct _GdkX11GLContextGLX
   GdkX11GLContext parent_instance;
 
   GLXContext glx_context;
-  GLXDrawable attached_drawable;
-  GLXDrawable unattached_drawable;
 
 #ifdef HAVE_XDAMAGE
   GLsync frame_fence;
@@ -49,38 +47,45 @@ typedef struct _GdkX11GLContextClass    GdkX11GLContextGLXClass;
 typedef struct {
   GdkDisplay *display;
 
-  GLXDrawable glx_drawable;
-
-  Window dummy_xwin;
-  GLXWindow dummy_glx;
-
   guint32 last_frame_counter;
 } DrawableInfo;
 
 G_DEFINE_TYPE (GdkX11GLContextGLX, gdk_x11_gl_context_glx, GDK_TYPE_X11_GL_CONTEXT)
 
-static void
-drawable_info_free (gpointer data_)
+static GLXDrawable
+gdk_x11_surface_get_glx_drawable (GdkSurface *surface)
 {
-  DrawableInfo *data = data_;
-  Display *dpy;
+  GdkX11Surface *self = GDK_X11_SURFACE (surface);
+  GdkDisplay *display = gdk_surface_get_display (GDK_SURFACE (self));
+  GdkX11Display *display_x11 = GDK_X11_DISPLAY (display);
 
-  gdk_x11_display_error_trap_push (data->display);
+  if (self->glx_drawable)
+    return self->glx_drawable;
 
-  dpy = gdk_x11_display_get_xdisplay (data->display);
+  self->glx_drawable = glXCreateWindow (gdk_x11_display_get_xdisplay (display),
+                                        display_x11->glx_config,
+                                        gdk_x11_surface_get_xid (surface),
+                                        NULL);
 
-  if (data->glx_drawable)
-    glXDestroyWindow (dpy, data->glx_drawable);
+  return self->glx_drawable;
+}
 
-  if (data->dummy_glx)
-    glXDestroyWindow (dpy, data->dummy_glx);
+void
+gdk_x11_surface_destroy_glx_drawable (GdkX11Surface *self)
+{
+  if (self->glx_drawable == None)
+    return;
 
-  if (data->dummy_xwin)
-    XDestroyWindow (dpy, data->dummy_xwin);
+  glXDestroyWindow (gdk_x11_display_get_xdisplay (gdk_surface_get_display (GDK_SURFACE (self))),
+                    self->glx_drawable);
 
-  gdk_x11_display_error_trap_pop_ignored (data->display);
+  self->glx_drawable = None;
+}
 
-  g_slice_free (DrawableInfo, data);
+static void
+drawable_info_free (gpointer data_)
+{
+  g_slice_free (DrawableInfo, data_);
 }
 
 static DrawableInfo *
@@ -123,6 +128,21 @@ maybe_wait_for_vblank (GdkDisplay  *display,
     }
 }
 
+static GLXDrawable
+gdk_x11_gl_context_glx_get_drawable (GdkX11GLContextGLX *self)
+{
+  GdkX11GLContext *context_x11 = GDK_X11_GL_CONTEXT (self);
+  GdkDrawContext *draw_context = GDK_DRAW_CONTEXT (self);
+  GdkSurface *surface;
+
+  if (context_x11->is_attached || gdk_draw_context_is_in_frame (draw_context))
+    surface = gdk_draw_context_get_surface (draw_context);
+  else
+    surface = GDK_X11_DISPLAY (gdk_draw_context_get_display (draw_context))->leader_gdk_surface;
+
+  return gdk_x11_surface_get_glx_drawable (surface);
+}
+
 static void
 gdk_x11_gl_context_glx_end_frame (GdkDrawContext *draw_context,
                                   cairo_region_t *painted)
@@ -145,7 +165,7 @@ gdk_x11_gl_context_glx_end_frame (GdkDrawContext *draw_context,
 
   info = get_glx_drawable_info (surface);
 
-  drawable = context_glx->attached_drawable;
+  drawable = gdk_x11_surface_get_glx_drawable (surface);
 
   GDK_DISPLAY_NOTE (display, OPENGL,
             g_message ("Flushing GLX buffers for drawable %lu (window: %lu), frame sync: %s",
@@ -232,7 +252,7 @@ gdk_x11_gl_context_glx_get_damage (GdkGLContext *context)
       shared_glx = GDK_X11_GL_CONTEXT_GLX (shared);
 
       gdk_gl_context_make_current (shared);
-      glXQueryDrawable (dpy, shared_glx->attached_drawable,
+      glXQueryDrawable (dpy, gdk_x11_gl_context_glx_get_drawable (shared_glx),
                         GLX_BACK_BUFFER_AGE_EXT, &buffer_age);
 
       switch (buffer_age)
@@ -591,53 +611,13 @@ gdk_x11_gl_context_glx_realize (GdkGLContext  *context,
   info = get_glx_drawable_info (surface);
   if (info == NULL)
     {
-      XSetWindowAttributes attrs;
-      unsigned long mask;
-
-      gdk_x11_display_error_trap_push (display);
-
       info = g_slice_new0 (DrawableInfo);
       info->display = display;
       info->last_frame_counter = 0;
 
-      attrs.override_redirect = True;
-      attrs.colormap = gdk_x11_display_get_window_colormap (display_x11);
-      attrs.border_pixel = 0;
-      mask = CWOverrideRedirect | CWColormap | CWBorderPixel;
-      info->dummy_xwin = XCreateWindow (dpy, DefaultRootWindow (dpy),
-                                        -100, -100, 1, 1,
-                                        0,
-                                        gdk_x11_display_get_window_depth (display_x11),
-                                        CopyFromParent,
-                                        gdk_x11_display_get_window_visual (display_x11),
-                                        mask,
-                                        &attrs);
-      XMapWindow(dpy, info->dummy_xwin);
-
-      info->glx_drawable = glXCreateWindow (dpy, display_x11->glx_config,
-                                            gdk_x11_surface_get_xid (surface),
-                                            NULL);
-      info->dummy_glx = glXCreateWindow (dpy, display_x11->glx_config, info->dummy_xwin, NULL);
-
-      if (gdk_x11_display_error_trap_pop (display))
-        {
-          g_set_error_literal (error, GDK_GL_ERROR,
-                               GDK_GL_ERROR_NOT_AVAILABLE,
-                               _("Unable to create a GL context"));
-
-          drawable_info_free (info);
-          glXDestroyContext (dpy, context_glx->glx_context);
-          context_glx->glx_context = NULL;
-
-          return FALSE;
-        }
-
       set_glx_drawable_info (surface, info);
     }
 
-  context_glx->attached_drawable = info->glx_drawable;
-  context_glx->unattached_drawable = info->dummy_glx;
-
   GDK_DISPLAY_NOTE (display, OPENGL,
             g_message ("Realized GLX context[%p], %s, version: %d.%d",
                        context_glx->glx_context,
@@ -888,10 +868,7 @@ gdk_x11_gl_context_glx_make_current (GdkDisplay   *display,
     }
 
   context_x11 = GDK_X11_GL_CONTEXT (context);
-  if (context_x11->is_attached || gdk_draw_context_is_in_frame (GDK_DRAW_CONTEXT (context)))
-    drawable = context_glx->attached_drawable;
-  else
-    drawable = context_glx->unattached_drawable;
+  drawable = gdk_x11_gl_context_glx_get_drawable (context_glx);
 
   GDK_DISPLAY_NOTE (display, OPENGL,
                     g_message ("Making GLX context %p current to drawable %lu",
diff --git a/gdk/x11/gdkglcontext-x11.h b/gdk/x11/gdkglcontext-x11.h
index 7dbd4d9ba5..f26425c7cb 100644
--- a/gdk/x11/gdkglcontext-x11.h
+++ b/gdk/x11/gdkglcontext-x11.h
@@ -101,6 +101,7 @@ gboolean                gdk_x11_display_init_egl                (GdkX11Display *
                                                                  Visual       **out_visual,
                                                                  int           *out_depth);
 void                    gdk_x11_surface_destroy_egl_surface     (GdkX11Surface *self);
+void                    gdk_x11_surface_destroy_glx_drawable    (GdkX11Surface *self);
 
 GType                   gdk_x11_gl_context_egl_get_type         (void) G_GNUC_CONST;
 GdkX11GLContext *       gdk_x11_gl_context_egl_new              (GdkSurface    *surface,
diff --git a/gdk/x11/gdksurface-x11.c b/gdk/x11/gdksurface-x11.c
index bffcdab011..eee5d2305b 100644
--- a/gdk/x11/gdksurface-x11.c
+++ b/gdk/x11/gdksurface-x11.c
@@ -757,6 +757,7 @@ gdk_x11_surface_finalize (GObject *object)
   _gdk_x11_surface_grab_check_destroy (GDK_SURFACE (impl));
 
   gdk_x11_surface_destroy_egl_surface (impl);
+  gdk_x11_surface_destroy_glx_drawable (impl);
 
   if (!GDK_SURFACE_DESTROYED (impl))
     {
diff --git a/gdk/x11/gdksurface-x11.h b/gdk/x11/gdksurface-x11.h
index cb8f92307f..e2828c87e6 100644
--- a/gdk/x11/gdksurface-x11.h
+++ b/gdk/x11/gdksurface-x11.h
@@ -88,6 +88,7 @@ struct _GdkX11Surface
 
   cairo_surface_t *cairo_surface;
   /* EGLSurface */ gpointer egl_surface;
+  /* GLXDrawable */ XID glx_drawable;
 
   int abs_x;
   int abs_y;