[gtk+] Use eglGetPlatformDisplay{,EXT} if available

[Matthias Clasen <matthiasc src gnome org>]

commit 434ce02ebee59418afb88109399ad37abf411300
Author: Adam Jackson <ajax redhat com>
Date:   Mon Oct 10 14:12:40 2016 -0400

    Use eglGetPlatformDisplay{,EXT} if available
    
    Calling eglGetDisplay forces libEGL to guess what kind of pointer you
    passed it. Different EGL libraries will do different things here, and in
    particular glvnd will do something different than Mesa. Since we do have
    an API that allows us to explicitly type the display, use it.
    
    The explicit call to eglGetProcAddress is working around a bug in
    libepoxy 1.3, which does not understand the EGL concept of client
    extensions. Since it does not, the normal epoxy resolver for
    eglGetPlatformDisplayEXT would not find any provider for that entry
    point, and crash when you attempted to call it.
    
    Signed-off-by: Adam Jackson <ajax redhat com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=772415

 gdk/wayland/gdkglcontext-wayland.c |   37 +++++++++++++++++++++++++++++++++++-
 gtk/inspector/general.c            |   36 ++++++++++++++++++++++++++++++++++-
 2 files changed, 71 insertions(+), 2 deletions(-)
---
diff --git a/gdk/wayland/gdkglcontext-wayland.c b/gdk/wayland/gdkglcontext-wayland.c
index ae1354e..6573688 100644
--- a/gdk/wayland/gdkglcontext-wayland.c
+++ b/gdk/wayland/gdkglcontext-wayland.c
@@ -274,6 +274,40 @@ gdk_wayland_gl_context_init (GdkWaylandGLContext *self)
 {
 }
 
+static EGLDisplay
+gdk_wayland_get_display (GdkWaylandDisplay *display_wayland)
+{
+  EGLDisplay dpy = NULL;
+
+  if (epoxy_has_egl_extension (NULL, "EGL_KHR_platform_base"))
+    {
+      PFNEGLGETPLATFORMDISPLAYPROC getPlatformDisplay =
+       (void *) eglGetProcAddress ("eglGetPlatformDisplay");
+
+      if (getPlatformDisplay)
+       dpy = getPlatformDisplay (EGL_PLATFORM_WAYLAND_EXT,
+                                 display_wayland->wl_display,
+                                 NULL);
+      if (dpy)
+       return dpy;
+    }
+
+  if (epoxy_has_egl_extension (NULL, "EGL_EXT_platform_base"))
+    {
+      PFNEGLGETPLATFORMDISPLAYEXTPROC getPlatformDisplay =
+       (void *) eglGetProcAddress ("eglGetPlatformDisplayEXT");
+
+      if (getPlatformDisplay)
+       dpy = getPlatformDisplay (EGL_PLATFORM_WAYLAND_EXT,
+                                 display_wayland->wl_display,
+                                 NULL);
+      if (dpy)
+       return dpy;
+    }
+
+  return eglGetDisplay ((EGLNativeDisplayType) display_wayland->wl_display);
+}
+
 gboolean
 gdk_wayland_display_init_gl (GdkDisplay *display)
 {
@@ -284,7 +318,8 @@ gdk_wayland_display_init_gl (GdkDisplay *display)
   if (display_wayland->have_egl)
     return TRUE;
 
-  dpy = eglGetDisplay ((EGLNativeDisplayType)display_wayland->wl_display);
+  dpy = gdk_wayland_get_display (display_wayland);
+
   if (dpy == NULL)
     return FALSE;
 
diff --git a/gtk/inspector/general.c b/gtk/inspector/general.c
index 77d0a76..f7f8223 100644
--- a/gtk/inspector/general.c
+++ b/gtk/inspector/general.c
@@ -214,6 +214,40 @@ append_egl_extension_row (GtkInspectorGeneral *gen,
 {
   add_check_row (gen, GTK_LIST_BOX (gen->priv->gl_box), ext, epoxy_has_egl_extension (dpy, ext), 0);
 }
+
+static EGLDisplay
+wayland_get_display (GdkWaylandDisplay *display_wayland)
+{
+  EGLDisplay dpy = NULL;
+
+  if (epoxy_has_egl_extension (NULL, "EGL_KHR_platform_base"))
+    {
+      PFNEGLGETPLATFORMDISPLAYPROC getPlatformDisplay =
+        (void *) eglGetProcAddress ("eglGetPlatformDisplay");
+
+      if (getPlatformDisplay)
+        dpy = getPlatformDisplay (EGL_PLATFORM_WAYLAND_EXT,
+                                  display_wayland->wl_display,
+                                  NULL);
+      if (dpy)
+        return dpy;
+    }
+
+  if (epoxy_has_egl_extension (NULL, "EGL_EXT_platform_base"))
+    {
+      PFNEGLGETPLATFORMDISPLAYEXTPROC getPlatformDisplay =
+        (void *) eglGetProcAddress ("eglGetPlatformDisplayEXT");
+
+      if (getPlatformDisplay)
+        dpy = getPlatformDisplay (EGL_PLATFORM_WAYLAND_EXT,
+                                  display_wayland->wl_display,
+                                  NULL);
+      if (dpy)
+        return dpy;
+    }
+
+  return eglGetDisplay ((EGLNativeDisplayType) display_wayland->wl_display);
+}
 #endif
 
 
@@ -254,7 +288,7 @@ init_gl (GtkInspectorGeneral *gen)
       EGLint major, minor;
       gchar *version;
 
-      dpy = eglGetDisplay ((EGLNativeDisplayType)gdk_wayland_display_get_wl_display (display));
+      dpy = wayland_get_display (gdk_wayland_display_get_wl_display (display));
 
       if (!eglInitialize (dpy, &major, &minor))
         return;