From 4f937221b421f3c63856af69e4d620a7f8b0a6b0 Mon Sep 17 00:00:00 2001
From: mittorn <mittorn@sibmail.com>
Date: Thu, 12 May 2016 22:42:46 +0000
Subject: [PATCH] Add some checks

---
 GL/glesinterface.h | 1 -
 eglwrap.cpp        | 6 +++++-
 nanogl.cpp         | 7 +++++--
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/GL/glesinterface.h b/GL/glesinterface.h
index 46de9e4..e8d42da 100644
--- a/GL/glesinterface.h
+++ b/GL/glesinterface.h
@@ -36,7 +36,6 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 struct GlESInterface
     {
-
     int (*eglChooseConfig) (int dpy, const int *attrib_list, int *configs, int config_size, int *num_config) S;
 	int (*eglCopyBuffers) (int dpy, int surface, void* target) S;
     int (*eglCreateContext) (int dpy, int config, int share_list, const int *attrib_list) S;
diff --git a/eglwrap.cpp b/eglwrap.cpp
index ab57519..0e6bd20 100644
--- a/eglwrap.cpp
+++ b/eglwrap.cpp
@@ -28,7 +28,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 extern "C++" GlESInterface* glEsImpl;
 extern "C++" void FlushOnStateChange();
-
+void gl_unimplemented();
 
 EGLint eglGetError (void)
     {
@@ -159,10 +159,14 @@ EGLContext eglGetCurrentContext (void)
     }
 EGLSurface eglGetCurrentSurface (EGLint readdraw)
     {
+	if( (void*)glEsImpl->eglGetCurrentSurface == (void*)gl_unimplemented )
+		return EGL_NO_SURFACE;
     return glEsImpl->eglGetCurrentSurface(readdraw);
     }
 EGLDisplay eglGetCurrentDisplay (void)
     {
+	if( (void*)glEsImpl->eglGetCurrentDisplay == (void*)gl_unimplemented )
+		return EGL_NO_DISPLAY;
     return glEsImpl->eglGetCurrentDisplay();
     }
     
diff --git a/nanogl.cpp b/nanogl.cpp
index 9130cec..11bd1ea 100644
--- a/nanogl.cpp
+++ b/nanogl.cpp
@@ -66,7 +66,7 @@ GlESInterface* glEsImpl = NULL;
 
 extern void InitGLStructs();
 
-static void gl_unimplemented() { 
+void gl_unimplemented() {
 	LOGE ("Called unimplemented OpenGL ES API\n"); 
 }
 
@@ -127,8 +127,11 @@ static int CreateGlEsInterface( const char * name, void * lib, void * lib1, void
 					LOGD ("<%s> @ 0x%p\n", *api, f);
 				}
 			}
-			else 
+			else
+			{
+				LOGE ( "libEGL.so not loaded!");
 				f = default_func;
+			}
 		}
 		else {
 			LOGD ("<%s> @ 0x%p\n", *api, f);
-- 
2.29.2