From 19aa3a4fca07ebda54b277e2e355c726c9ecaa4c Mon Sep 17 00:00:00 2001
From: Adam Jackson <ajax@redhat.com>
Date: Mon, 10 Oct 2016 14:12:40 -0400
Subject: [PATCH] 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 ae1354ef70..657368860f 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 77d0a767f1..35231b5b39 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 (struct wl_display *wl_display)
+{
+  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,
+                                  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,
+                                  wl_display,
+                                  NULL);
+      if (dpy)
+        return dpy;
+    }
+
+  return eglGetDisplay ((EGLNativeDisplayType)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;