[gtk+] Add support for GDK_GL=texture-rectangles

[Alexander Larsson <alexl src gnome org>]

commit 650c9f3b7eaade447aa341d7c8dd7d9a9aa10188
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Nov 6 11:29:51 2014 +0100

    Add support for GDK_GL=texture-rectangles
    
    This allows us to test our support for GL_ARB_texture_rectangle

 gdk/gdk.c          |    1 +
 gdk/gdkglcontext.c |    4 +++-
 gdk/gdkinternals.h |    1 +
 3 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdk.c b/gdk/gdk.c
index 2b44b0f..a4f1f62 100644
--- a/gdk/gdk.c
+++ b/gdk/gdk.c
@@ -140,6 +140,7 @@ static const GDebugKey gdk_gl_keys[] = {
   {"software-draw",         GDK_GL_FLAGS_SOFTWARE_DRAW_GL | GDK_GL_FLAGS_SOFTWARE_DRAW_SURFACE},
   {"software-draw-gl",      GDK_GL_FLAGS_SOFTWARE_DRAW_GL},
   {"software-draw-surface", GDK_GL_FLAGS_SOFTWARE_DRAW_SURFACE},
+  {"texture-rectangle",     GDK_GL_FLAGS_TEXTURE_RECTANGLE},
 };
 
 #ifdef G_ENABLE_DEBUG
diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index 1628e51..eef707c 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -359,7 +359,9 @@ gdk_gl_context_realize (GdkGLContext *context)
   has_npot = epoxy_has_gl_extension ("GL_ARB_texture_non_power_of_two");
   has_texture_rectangle = epoxy_has_gl_extension ("GL_ARB_texture_rectangle");
 
-  if (has_npot)
+  if (_gdk_gl_flags & GDK_GL_FLAGS_TEXTURE_RECTANGLE)
+    priv->use_texture_rectangle = TRUE;
+  else if (has_npot)
     priv->use_texture_rectangle = FALSE;
   else if (has_texture_rectangle)
     priv->use_texture_rectangle = TRUE;
diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index 3a6659b..14141bd 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -93,6 +93,7 @@ typedef enum {
   GDK_GL_FLAGS_ALWAYS                 = 1 << 1,
   GDK_GL_FLAGS_SOFTWARE_DRAW_GL       = 1 << 2,
   GDK_GL_FLAGS_SOFTWARE_DRAW_SURFACE  = 1 << 3,
+  GDK_GL_FLAGS_TEXTURE_RECTANGLE      = 1 << 4,
 } GdkGLFlags;