[mutter] backends: Add OpenGL ES 3 abstraction layer

[Jonas Ådahl <jadahl src gnome org>]

commit 60781bc6c25997adda83f719675d13a4be50bc21
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Jul 24 17:24:29 2017 +0800

    backends: Add OpenGL ES 3 abstraction layer
    
    Add helper functions and macros for managing and drawing OpenGL ES 3.
    It will be used for blitting framebuffers between multiple GPUs in
    hybrid GPU systems.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785381

 src/Makefile.am                 |    3 +
 src/backends/meta-gles3-table.h |   36 +++++++++
 src/backends/meta-gles3.c       |  163 +++++++++++++++++++++++++++++++++++++++
 src/backends/meta-gles3.h       |   83 ++++++++++++++++++++
 4 files changed, 285 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index a964275..c0d2a65 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -109,6 +109,9 @@ libmutter_@LIBMUTTER_API_VERSION@_la_SOURCES =      \
        backends/meta-egl.c                     \
        backends/meta-egl.h                     \
        backends/meta-egl-ext.h                 \
+       backends/meta-gles3.c                   \
+       backends/meta-gles3.h                   \
+       backends/meta-gles3-table.h             \
        backends/meta-gpu.c                     \
        backends/meta-gpu.h                     \
        backends/meta-display-config-shared.h   \
diff --git a/src/backends/meta-gles3-table.h b/src/backends/meta-gles3-table.h
new file mode 100644
index 0000000..4cc8660
--- /dev/null
+++ b/src/backends/meta-gles3-table.h
@@ -0,0 +1,36 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2017 Red Hat
+ *
+ * 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.
+ *
+ */
+
+#ifndef META_GLES3_TABLE_H
+#define META_GLES3_TABLE_H
+
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#include <GLES3/gl3.h>
+
+typedef struct _MetaGles3Table
+{
+  void (* glEGLImageTargetTexture2DOES) (GLenum        target,
+                                         GLeglImageOES image);
+} MetaGles3Table;
+
+#endif /* META_GLES3_TABLE */
diff --git a/src/backends/meta-gles3.c b/src/backends/meta-gles3.c
new file mode 100644
index 0000000..f467a8f
--- /dev/null
+++ b/src/backends/meta-gles3.c
@@ -0,0 +1,163 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2017 Red Hat
+ *
+ * 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.
+ *
+ */
+#include <stdio.h>
+
+#include "config.h"
+
+#include "backends/meta-gles3.h"
+
+#include <dlfcn.h>
+#include <gio/gio.h>
+
+#include "backends/meta-gles3-table.h"
+
+struct _MetaGles3
+{
+  GObject parent;
+
+  MetaEgl *egl;
+
+  MetaGles3Table table;
+};
+
+G_DEFINE_TYPE (MetaGles3, meta_gles3, G_TYPE_OBJECT)
+
+MetaGles3Table *
+meta_gles3_get_table (MetaGles3 *gles3)
+{
+  return &gles3->table;
+}
+
+void
+meta_gles3_ensure_loaded (MetaGles3  *gles3,
+                          gpointer   *func,
+                          const char *name)
+{
+  GError *error = NULL;
+
+  if (*func)
+    return;
+
+  *func = meta_egl_get_proc_address (gles3->egl, name, &error);
+  if (!*func)
+    g_error ("Failed to load GLES3 symbol: %s", error->message);
+}
+
+static const char *
+get_gl_error_str (GLenum gl_error)
+{
+  switch (gl_error)
+    {
+    case GL_NO_ERROR:
+      return "No error has been recorded.";
+    case GL_INVALID_ENUM:
+      return "An unacceptable value is specified for an enumerated argument.";
+    case GL_INVALID_VALUE:
+        return "A numeric argument is out of range.";
+    case GL_INVALID_OPERATION:
+        return "The specified operation is not allowed in the current state.";
+    case GL_INVALID_FRAMEBUFFER_OPERATION:
+        return "The framebuffer object is not complete.";
+    case GL_OUT_OF_MEMORY:
+        return "There is not enough memory left to execute the command.";
+    default:
+        return "Unknown error";
+    }
+}
+
+void
+meta_gles3_clear_error (MetaGles3 *gles3)
+{
+  while (TRUE)
+    {
+      GLenum gl_error = glGetError ();
+
+      if (gl_error == GL_NO_ERROR)
+        break;
+    }
+}
+
+gboolean
+meta_gles3_validate (MetaGles3 *gles3,
+                     GError   **error)
+{
+  GLenum gl_error;
+
+  gl_error = glGetError ();
+  if (gl_error != GL_NO_ERROR)
+    {
+      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                           get_gl_error_str (gl_error));
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+gboolean
+meta_gles3_has_extensions (MetaGles3 *gles3,
+                           char    ***missing_extensions,
+                           char      *first_extension,
+                           ...)
+{
+  va_list var_args;
+  const char *extensions_str;
+  gboolean has_extensions;
+
+  extensions_str = (const char *) glGetString (GL_EXTENSIONS);
+  if (!extensions_str)
+    {
+      g_warning ("Failed to get string: %s", get_gl_error_str (glGetError ()));
+      return FALSE;
+    }
+
+  va_start (var_args, first_extension);
+  has_extensions =
+    meta_extensions_string_has_extensions_valist (extensions_str,
+                                                  missing_extensions,
+                                                  first_extension,
+                                                  var_args);
+  va_end (var_args);
+
+  return has_extensions;
+}
+
+MetaGles3 *
+meta_gles3_new (MetaEgl *egl)
+{
+  MetaGles3 *gles3;
+
+  gles3 = g_object_new (META_TYPE_GLES3, NULL);
+  gles3->egl = egl;
+
+  return gles3;
+}
+
+static void
+meta_gles3_init (MetaGles3 *gles3)
+{
+}
+
+static void
+meta_gles3_class_init (MetaGles3Class *klass)
+{
+}
diff --git a/src/backends/meta-gles3.h b/src/backends/meta-gles3.h
new file mode 100644
index 0000000..6f42be2
--- /dev/null
+++ b/src/backends/meta-gles3.h
@@ -0,0 +1,83 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2017 Red Hat
+ *
+ * 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.
+ *
+ */
+
+#ifndef META_GLES3_H
+#define META_GLES3_H
+
+#include <glib-object.h>
+
+#include "backends/meta-egl.h"
+
+typedef struct _MetaGles3Table MetaGles3Table;
+
+#define META_TYPE_GLES3 (meta_gles3_get_type ())
+G_DECLARE_FINAL_TYPE (MetaGles3, meta_gles3, META, GLES3, GObject)
+
+MetaGles3Table * meta_gles3_get_table (MetaGles3 *gles3);
+
+void meta_gles3_clear_error (MetaGles3 *gles3);
+
+gboolean meta_gles3_validate (MetaGles3 *gles3,
+                              GError   **error);
+
+void meta_gles3_ensure_loaded (MetaGles3  *gles,
+                               gpointer   *func,
+                               const char *name);
+
+gboolean meta_gles3_has_extensions (MetaGles3 *gles3,
+                                    char    ***missing_extensions,
+                                    char      *first_extension,
+                                    ...);
+
+MetaGles3 * meta_gles3_new (MetaEgl *egl);
+
+#define GLBAS(gles3, func, args)                                               \
+{                                                                              \
+  GError *_error = NULL;                                                       \
+                                                                               \
+  func args;                                                                   \
+                                                                               \
+  if (!meta_gles3_validate (gles3, &_error))                                   \
+    {                                                                          \
+      g_warning ("%s %s failed: %s", #func, #args, _error->message);           \
+      g_error_free (_error);                                                   \
+    }                                                                          \
+}
+
+#define GLEXT(gles3, func, args)                                               \
+{                                                                              \
+  GError *_error = NULL;                                                       \
+  MetaGles3Table *table;                                                       \
+                                                                               \
+  table = meta_gles3_get_table (gles3);                                        \
+  meta_gles3_ensure_loaded (gles3, (gpointer *) &table->func, #func);          \
+                                                                               \
+  table->func args;                                                            \
+                                                                               \
+  if (!meta_gles3_validate (gles3, &_error))                                   \
+    {                                                                          \
+      g_warning ("%s %s failed: %s", #func, #args, _error->message);           \
+      g_error_free (_error);                                                   \
+    }                                                                          \
+}
+
+#endif /* META_GLES3_H */