glesv2: check for null pointers in glGetString

glGetString may return NULL pointers when OpenGL has not been correctly
initialized. This assert makes such errors easier to debug on mobile
devices when there's no stacktrace.

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/glesv2/glesv2.nit b/lib/glesv2/glesv2.nit
index b8e0bcb..6c52083 100644 (file)
--- a/lib/glesv2/glesv2.nit
+++ b/lib/glesv2/glesv2.nit
@@ -1328,7 +1328,13 @@ fun gl_FRAMEBUFFER_BINDING: GLGetParameterName `{ return GL_FRAMEBUFFER_BINDING;
 fun gl_RENDERBUFFER_BINDING: GLGetParameterName `{ return GL_RENDERBUFFER_BINDING; `}
 
 # Return a string describing the current GL configuration
-fun glGetString(name: GLEnum): String do return glGetString_native(name).to_s
+fun glGetString(name: GLEnum): String
+do
+       var cstr = glGetString_native(name)
+       assert not cstr.address_is_null
+       return cstr.to_s
+end
+
 private fun glGetString_native(name: GLEnum): CString `{ return (char*)glGetString(name); `}
 
 # Company responsible for this GL implementation