[gnome-session] Add a helper to check if session can run on GLES

[Cosimo Cecchi <cosimoc src gnome org>]

commit 143dfdcc3999ef861978bdb0c34ec04ae6ea5aca
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Sun Apr 3 19:08:41 2016 -0700

    Add a helper to check if session can run on GLES
    
    This is needed on platforms where GLX is not typically available, such
    as when running on an ARM Mali chipset.
    The helper is currently not wired, but it will be in a later commit.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=686806

 configure.ac                                       |    1 +
 tools/Makefile.am                                  |   19 ++-
 .../gnome-session-check-accelerated-gles-helper.c  |  191 ++++++++++++++++++++
 3 files changed, 210 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index a0dc4d3..2975578 100644
--- a/configure.ac
+++ b/configure.ac
@@ -86,6 +86,7 @@ PKG_CHECK_MODULES(ICE, ice)
 PKG_CHECK_MODULES(XEXT, xext xau)
 
 PKG_CHECK_MODULES(GL_TEST, xcomposite gl glib-2.0)
+PKG_CHECK_MODULES(GLES_TEST, egl glesv2)
 
 dnl ====================================================================
 dnl Check for gconf
diff --git a/tools/Makefile.am b/tools/Makefile.am
index 599c891..23cafc9 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -1,5 +1,8 @@
 bin_PROGRAMS = gnome-session-quit gnome-session-inhibit
-libexec_PROGRAMS = gnome-session-check-accelerated gnome-session-check-accelerated-gl-helper
+libexec_PROGRAMS = \
+       gnome-session-check-accelerated \
+       gnome-session-check-accelerated-gl-helper \
+       gnome-session-check-accelerated-gles-helper
 
 if BUILD_SESSION_SELECTOR
 bin_PROGRAMS += gnome-session-selector
@@ -41,6 +44,20 @@ gnome_session_inhibit_CPPFLAGS =             \
 gnome_session_inhibit_LDADD =                  \
        $(GNOME_SESSION_LIBS)
 
+gnome_session_check_accelerated_gles_helper_SOURCES =          \
+       gnome-session-check-accelerated-common.h                \
+       gnome-session-check-accelerated-gles-helper.c
+
+gnome_session_check_accelerated_gles_helper_CPPFLAGS = \
+       -DPKGDATADIR=\""$(pkgdatadir)"\"                \
+       $(GLES_TEST_CFLAGS)                             \
+       $(GTK3_CFLAGS)
+
+gnome_session_check_accelerated_gles_helper_LDADD =    \
+       $(GLES_TEST_LIBS)                               \
+       $(GTK3_LIBS)                                    \
+       $(X11_LIBS)
+
 gnome_session_check_accelerated_gl_helper_SOURCES =            \
        gnome-session-check-accelerated-common.h                \
        gnome-session-check-accelerated-gl-helper.c
diff --git a/tools/gnome-session-check-accelerated-gles-helper.c 
b/tools/gnome-session-check-accelerated-gles-helper.c
new file mode 100644
index 0000000..4a6b6a2
--- /dev/null
+++ b/tools/gnome-session-check-accelerated-gles-helper.c
@@ -0,0 +1,191 @@
+/* -*- mode:c; c-basic-offset: 8; indent-tabs-mode: nil; -*- */
+/*
+ *
+ * Copyright (C) 2016 Endless Mobile, Inc
+ *
+ * This program 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 Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Author:
+ *   Cosimo Cecchi <cosimo endlessm com>
+ */
+
+#include <config.h>
+
+#include <gtk/gtk.h>
+#include <stdlib.h>
+
+#ifdef GDK_WINDOWING_X11
+#define GL_GLEXT_PROTOTYPES
+
+#include <gdk/gdkx.h>
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#include <EGL/egl.h>
+#endif
+
+#include "gnome-session-check-accelerated-common.h"
+
+#ifdef GDK_WINDOWING_X11
+static char *
+get_gles_renderer (void)
+{
+        /* Select GLESv2 config */
+        EGLint attribs[] = {
+                EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+                EGL_RED_SIZE, 1,
+                EGL_GREEN_SIZE, 1,
+                EGL_BLUE_SIZE, 1,
+                EGL_NONE
+        };
+
+        EGLint ctx_attribs[] = {
+                EGL_CONTEXT_CLIENT_VERSION, 2,
+                EGL_NONE
+        };
+
+        gboolean egl_inited = FALSE;
+        Display *display;
+        Window win = None;
+        EGLContext egl_ctx = NULL;
+        EGLDisplay egl_dpy = NULL;
+        EGLSurface egl_surf = NULL;
+        char *renderer = NULL;
+
+        gdk_error_trap_push ();
+
+        display = GDK_DISPLAY_XDISPLAY (gdk_display_get_default ());
+        egl_dpy = eglGetDisplay (display);
+        if (!egl_dpy) {
+                g_warning ("eglGetDisplay() failed");
+                goto out;
+        }
+
+        EGLint egl_major, egl_minor;
+        if (!eglInitialize (egl_dpy, &egl_major, &egl_minor)) {
+                g_warning ("eglInitialize() failed");
+                goto out;
+        }
+
+        egl_inited = TRUE;
+
+        EGLint num_configs;
+        EGLConfig config;
+        if (!eglChooseConfig (egl_dpy, attribs, &config, 1, &num_configs)) {
+                g_warning ("Failed to get EGL configuration");
+                goto out;
+        }
+
+        EGLint vid;
+        if (!eglGetConfigAttrib (egl_dpy, config, EGL_NATIVE_VISUAL_ID, &vid)) {
+                g_warning ("Failed to get EGL visual");
+                goto out;
+        }
+
+        /* The X window visual must match the EGL config */
+        XVisualInfo *vis_info, vis_template;
+        int num_visuals;
+        vis_template.visualid = vid;
+        vis_info = XGetVisualInfo (display, VisualIDMask, &vis_template, &num_visuals);
+        if (!vis_info) {
+                g_warning ("Failed to get X visual");
+                goto out;
+        }
+
+        XSetWindowAttributes attr;
+        attr.colormap = XCreateColormap (display, DefaultRootWindow (display),
+                                         vis_info->visual, AllocNone);
+        win = XCreateWindow (display, DefaultRootWindow (display),
+                             0, 0, /* x, y */
+                             1, 1, /* width, height */
+                             0,    /* border_width */
+                             vis_info->depth, InputOutput,
+                             vis_info->visual, CWColormap, &attr);
+        XFree (vis_info);
+
+        eglBindAPI (EGL_OPENGL_ES_API);
+
+        egl_ctx = eglCreateContext (egl_dpy, config, EGL_NO_CONTEXT, ctx_attribs);
+        if (!egl_ctx) {
+                g_warning ("Failed to create EGL context");
+                goto out;
+        }
+
+        egl_surf = eglCreateWindowSurface (egl_dpy, config, win, NULL);
+        if (!egl_surf) {
+                g_warning ("Failed to create EGL surface");
+                goto out;
+        }
+
+        if (!eglMakeCurrent (egl_dpy, egl_surf, egl_surf, egl_ctx)) {
+                g_warning ("eglMakeCurrent() failed");
+                goto out;
+        }
+
+        renderer = g_strdup ((const char *) glGetString (GL_RENDERER));
+
+ out:
+        if (egl_ctx)
+                eglDestroyContext (egl_dpy, egl_ctx);
+        if (egl_surf)
+                eglDestroySurface (egl_dpy, egl_surf);
+        if (egl_inited)
+                eglTerminate (egl_dpy);
+        if (win != None)
+                XDestroyWindow (display, win);
+
+        gdk_error_trap_pop_ignored ();
+        return renderer;
+}
+#endif
+
+static gboolean print_renderer = FALSE;
+
+static const GOptionEntry entries[] = {
+        { "print-renderer", 'p', 0, G_OPTION_ARG_NONE, &print_renderer, "Print EGL renderer name", NULL },
+        { NULL },
+};
+
+int
+main (int argc,
+      char **argv)
+{
+        char *renderer = NULL;
+        GOptionContext *context;
+        int ret = HELPER_NO_ACCEL;
+        GError *error = NULL;
+
+        context = g_option_context_new (NULL);
+        g_option_context_add_group (context, gtk_get_option_group (TRUE));
+        g_option_context_add_main_entries (context, entries, NULL);
+
+        if (!g_option_context_parse (context, &argc, &argv, &error)) {
+                g_error ("Can't parse command line: %s\n", error->message);
+                g_error_free (error);
+                goto out;
+        }
+
+#ifdef GDK_WINDOWING_X11
+        renderer = get_gles_renderer ();
+#endif
+
+        if (renderer != NULL) {
+                if (print_renderer)
+                        g_print ("%s", renderer);
+                ret = HELPER_ACCEL;
+        }
+
+out:
+        return ret;
+}