[gtk+] gl: Add gdk_gl_context_get_version()

[Emmanuele Bassi <ebassi src gnome org>]

commit 390a42fa605e99362ac307bf568113dcdad41cdc
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Feb 12 14:28:22 2015 +0000

    gl: Add gdk_gl_context_get_version()
    
    Store the OpenGL version when we first do the extensions check; this
    allows client code to check the available GL version without requiring a
    call to gdk_gl_context_make_current() and epoxy_gl_version().

 docs/reference/gdk/gdk3-sections.txt |    5 ++++
 gdk/gdkglcontext.c                   |   35 +++++++++++++++++++++++++++++++++-
 gdk/gdkglcontext.h                   |    4 +++
 3 files changed, 43 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gdk/gdk3-sections.txt b/docs/reference/gdk/gdk3-sections.txt
index e90b782..7335636 100644
--- a/docs/reference/gdk/gdk3-sections.txt
+++ b/docs/reference/gdk/gdk3-sections.txt
@@ -1291,6 +1291,9 @@ GdkGLContext
 gdk_gl_context_get_display
 gdk_gl_context_get_window
 gdk_gl_context_get_shared_context
+gdk_gl_context_get_version
+
+<SUBSECTION>
 gdk_gl_context_set_required_version
 gdk_gl_context_get_required_version
 gdk_gl_context_set_debug_enabled
@@ -1300,6 +1303,8 @@ gdk_gl_context_get_forward_compatible
 GdkGLProfile
 gdk_gl_context_set_profile
 gdk_gl_context_get_profile
+
+<SUBSECTION>
 GdkGLError
 gdk_gl_context_realize
 gdk_gl_context_make_current
diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index ec6c0a5..1ffacca 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -95,6 +95,7 @@ typedef struct {
 
   int major;
   int minor;
+  int gl_version;
 
   guint realized : 1;
   guint use_texture_rectangle : 1;
@@ -617,6 +618,8 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
   if (priv->extensions_checked)
     return;
 
+  priv->gl_version = epoxy_gl_version ();
+
   has_npot = epoxy_has_gl_extension ("GL_ARB_texture_non_power_of_two");
   has_texture_rectangle = epoxy_has_gl_extension ("GL_ARB_texture_rectangle");
 
@@ -633,12 +636,14 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
     g_warning ("GL implementation doesn't support any form of non-power-of-two textures");
 
   GDK_NOTE (OPENGL,
-            g_print ("Extensions checked:\n"
+            g_print ("OpenGL version: %d.%d\n"
+                     "Extensions checked:\n"
                      " - GL_ARB_texture_non_power_of_two: %s\n"
                      " - GL_ARB_texture_rectangle: %s\n"
                      " - GL_EXT_framebuffer_blit: %s\n"
                      " - GL_GREMEDY_frame_terminator: %s\n"
                      "Using texture rectangle: %s\n",
+                     priv->gl_version / 10, priv->gl_version % 10,
                      has_npot ? "yes" : "no",
                      has_texture_rectangle ? "yes" : "no",
                      priv->has_gl_framebuffer_blit ? "yes" : "no",
@@ -799,6 +804,34 @@ gdk_gl_context_get_shared_context (GdkGLContext *context)
 }
 
 /**
+ * gdk_gl_context_get_version:
+ * @context: a #GdkGLContext
+ * @major: (out): return location for the major version
+ * @minor: (out): return location for the minor version
+ *
+ * Retrieves the OpenGL version of the @context.
+ *
+ * The @context must be realized prior to calling this function.
+ *
+ * Since: 3.16
+ */
+void
+gdk_gl_context_get_version (GdkGLContext *context,
+                            int          *major,
+                            int          *minor)
+{
+  GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context);
+
+  g_return_if_fail (GDK_IS_GL_CONTEXT (context));
+  g_return_if_fail (priv->realized);
+
+  if (major != NULL)
+    *major = priv->gl_version / 10;
+  if (minor != NULL)
+    *minor = priv->gl_version % 10;
+}
+
+/**
  * gdk_gl_context_clear_current:
  *
  * Clears the current #GdkGLContext.
diff --git a/gdk/gdkglcontext.h b/gdk/gdkglcontext.h
index d6d5f39..089d746 100644
--- a/gdk/gdkglcontext.h
+++ b/gdk/gdkglcontext.h
@@ -48,6 +48,10 @@ GDK_AVAILABLE_IN_3_16
 GdkWindow *             gdk_gl_context_get_window               (GdkGLContext  *context);
 GDK_AVAILABLE_IN_3_16
 GdkGLContext *          gdk_gl_context_get_shared_context       (GdkGLContext  *context);
+GDK_AVAILABLE_IN_3_16
+void                    gdk_gl_context_get_version              (GdkGLContext  *context,
+                                                                 int           *major,
+                                                                 int           *minor);
 
 GDK_AVAILABLE_IN_3_16
 void                    gdk_gl_context_set_required_version     (GdkGLContext  *context,