Another patch by pc0de, fixing problems when combining material serialization with null driver.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1223 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/CNullDriver.cpp

@@ -1792,7 +1792,17 @@ void CNullDriver::printVersion()
 //! creates a video driver
 IVideoDriver* createNullDriver(io::IFileSystem* io, const core::dimension2d<s32>& screenSize)
 {
-	return new CNullDriver(io, screenSize);
+	CNullDriver* nullDriver = new CNullDriver(io, screenSize);
+
+	// create empty material renderers
+	for(u32 i=0; sBuiltInMaterialTypeNames[i]; ++i)
+	{
+		IMaterialRenderer* imr = new IMaterialRenderer();
+		nullDriver->addMaterialRenderer(imr);
+		imr->drop();
+	}
+
+	return nullDriver;
 }